From 34a166cdac6ec3145346d5c3df103dababb5ed5c Mon Sep 17 00:00:00 2001
From: Syoyo Fujita <syoyo@lighttransport.com>
Date: Mon, 1 Jun 2026 13:44:47 +0900
Subject: [PATCH] Complete freestanding v3 C JSON conversion tests

---
 CMakeLists.txt                 |  42 +++
 tests/Makefile                 |   8 +-
 tests/tester_v3_c.c            | 563 ++++++++++++++++++++++++++++
 tests/tester_v3_freestanding.c |  75 ++++
 tests/tester_v3_json_c.c       | 165 +++++++++
 tiny_gltf_v3.c                 | 365 ++++++++++++------
 tiny_gltf_v3.h                 |  30 ++
 tinygltf_json_c.h              | 649 +++++++++++++++++++++++++++------
 8 files changed, 1667 insertions(+), 230 deletions(-)
 create mode 100644 tests/tester_v3_freestanding.c
 create mode 100644 tests/tester_v3_json_c.c

diff --git a/CMakeLists.txt b/CMakeLists.txt
index dc97c29..8d9248d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -79,7 +79,49 @@ if (TINYGLTF_BUILD_TESTS)
     C_STANDARD_REQUIRED ON
     C_EXTENSIONS OFF
   )
+  target_compile_definitions(tester_v3_c PRIVATE TINYGLTF3_ENABLE_FS)
   add_test(NAME tester_v3_c COMMAND tester_v3_c WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/tests)
+
+  add_executable(tester_v3_c_v1port
+    tests/tester_v3_c_v1port.c
+    tiny_gltf_v3.c
+  )
+  target_include_directories(tester_v3_c_v1port PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}
+    ${CMAKE_CURRENT_SOURCE_DIR}/tests
+  )
+  set_target_properties(tester_v3_c_v1port PROPERTIES
+    C_STANDARD 11
+    C_STANDARD_REQUIRED ON
+    C_EXTENSIONS OFF
+  )
+  target_compile_definitions(tester_v3_c_v1port PRIVATE TINYGLTF3_ENABLE_FS)
+  add_test(NAME tester_v3_c_v1port COMMAND tester_v3_c_v1port WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/tests)
+
+  add_executable(tester_v3_json_c tests/tester_v3_json_c.c)
+  target_include_directories(tester_v3_json_c PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}
+  )
+  set_target_properties(tester_v3_json_c PROPERTIES
+    C_STANDARD 11
+    C_STANDARD_REQUIRED ON
+    C_EXTENSIONS OFF
+  )
+  add_test(NAME tester_v3_json_c COMMAND tester_v3_json_c WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/tests)
+
+  add_executable(tester_v3_freestanding tests/tester_v3_freestanding.c)
+  target_include_directories(tester_v3_freestanding PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}
+  )
+  set_target_properties(tester_v3_freestanding PROPERTIES
+    C_STANDARD 11
+    C_STANDARD_REQUIRED ON
+    C_EXTENSIONS OFF
+  )
+  if (CMAKE_C_COMPILER_ID MATCHES "Clang|GNU")
+    target_compile_options(tester_v3_freestanding PRIVATE -ffreestanding)
+  endif()
+  add_test(NAME tester_v3_freestanding COMMAND tester_v3_freestanding WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/tests)
 endif (TINYGLTF_BUILD_TESTS)
 
 #
diff --git a/tests/Makefile b/tests/Makefile
index 5b96996..7f161fb 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -1,7 +1,7 @@
 # Use this for strict compilation check(will work on clang 3.8+)
 #EXTRA_CXXFLAGS := -fsanitize=address -Wall -Werror -Weverything -Wno-c++11-long-long -DTINYGLTF_APPLY_CLANG_WEVERYTHING
 
-all: ../tiny_gltf.h tester_v3_c tester_v3_c_v1port
+all: ../tiny_gltf.h tester_v3_c tester_v3_c_v1port tester_v3_json_c tester_v3_freestanding
 	clang++  -I../ $(EXTRA_CXXFLAGS) -std=c++11 -g -O0 -o tester tester.cc
 	clang++ -DTINYGLTF_NOEXCEPTION -I../ $(EXTRA_CXXFLAGS) -std=c++11 -g -O0 -o tester_noexcept tester.cc
 	clang++ -DTINYGLTF_USE_CUSTOM_JSON -I../ $(EXTRA_CXXFLAGS) -std=c++11 -g -O0 -o tester_intensive_customjson tester_intensive_customjson.cc
@@ -11,3 +11,9 @@ tester_v3_c: tester_v3_c.c ../tiny_gltf_v3.h ../tiny_gltf_v3.c ../tinygltf_json_
 
 tester_v3_c_v1port: tester_v3_c_v1port.c ../tiny_gltf_v3.h ../tiny_gltf_v3.c ../tinygltf_json_c.h
 	clang -I../ -std=c11 -g -O0 -DTINYGLTF3_ENABLE_FS -o tester_v3_c_v1port tester_v3_c_v1port.c ../tiny_gltf_v3.c
+
+tester_v3_json_c: tester_v3_json_c.c ../tinygltf_json_c.h
+	clang -I../ -std=c11 -g -O0 -o tester_v3_json_c tester_v3_json_c.c
+
+tester_v3_freestanding: tester_v3_freestanding.c ../tiny_gltf_v3.h ../tiny_gltf_v3.c ../tinygltf_json_c.h
+	clang -I../ -std=c11 -ffreestanding -g -O0 -o tester_v3_freestanding tester_v3_freestanding.c
diff --git a/tests/tester_v3_c.c b/tests/tester_v3_c.c
index b565c1b..4e21a52 100644
--- a/tests/tester_v3_c.c
+++ b/tests/tester_v3_c.c
@@ -228,6 +228,16 @@ static int mem_contains(const uint8_t *data, uint64_t size, const char *needle)
   return 0;
 }
 
+static void write_u32le(uint8_t *dst, uint32_t v) {
+  memcpy(dst, &v, sizeof(v));
+}
+
+static uint32_t read_u32le(const uint8_t *src) {
+  uint32_t v;
+  memcpy(&v, src, sizeof(v));
+  return v;
+}
+
 static int check_minimal_parse(void) {
   static const uint8_t json[] =
       "{\"asset\":{\"version\":\"2.0\"},"
@@ -339,6 +349,529 @@ static int check_minimal_write_roundtrip(void) {
   return 1;
 }
 
+static int check_binary_write_roundtrip(void) {
+  static const char json[] =
+      "{\"asset\":{\"version\":\"2.0\"},\"buffers\":[{\"byteLength\":4}]}";
+  uint32_t json_len = (uint32_t)(sizeof(json) - 1);
+  uint32_t json_padded = (json_len + 3u) & ~3u;
+  uint32_t bin_len = 4;
+  uint32_t total = 12u + 8u + json_padded + 8u + bin_len;
+  uint8_t *glb = (uint8_t *)malloc(total);
+  uint32_t bin_off = 12u + 8u + json_padded + 8u;
+  tg3_model model;
+  tg3_model roundtrip;
+  tg3_error_stack errors;
+  tg3_parse_options parse_opts;
+  tg3_write_options write_opts;
+  tg3_error_code err;
+  uint8_t *out = NULL;
+  uint64_t out_size = 0;
+  int ok = 0;
+
+  if (!glb) return 0;
+  memset(glb, ' ', total);
+  memcpy(glb, "glTF", 4);
+  write_u32le(glb + 4, 2u);
+  write_u32le(glb + 8, total);
+  write_u32le(glb + 12, json_padded);
+  write_u32le(glb + 16, 0x4E4F534Au);
+  memcpy(glb + 20, json, json_len);
+  write_u32le(glb + 20 + json_padded, bin_len);
+  write_u32le(glb + 24 + json_padded, 0x004E4942u);
+  glb[bin_off + 0] = 1;
+  glb[bin_off + 1] = 2;
+  glb[bin_off + 2] = 3;
+  glb[bin_off + 3] = 4;
+
+  tg3_error_stack_init(&errors);
+  tg3_parse_options_init(&parse_opts);
+  parse_opts.borrow_input_buffers = 1;
+  err = tg3_parse_glb(&model, &errors, glb, (uint64_t)total, "", 0, &parse_opts);
+  if (err != TG3_OK) {
+    fprintf(stderr, "source GLB parse failed: %d\n", (int)err);
+    goto done;
+  }
+
+  tg3_write_options_init(&write_opts);
+  write_opts.write_binary = 1;
+  err = tg3_write_to_memory(&model, &errors, &out, &out_size, &write_opts);
+  if (err != TG3_OK || !out || out_size < 28 ||
+      memcmp(out, "glTF", 4) != 0 ||
+      read_u32le(out + 4) != 2u ||
+      read_u32le(out + 8) != (uint32_t)out_size ||
+      read_u32le(out + 16) != 0x4E4F534Au) {
+    fprintf(stderr, "binary write failed or produced invalid GLB: %d\n", (int)err);
+    goto done_model;
+  }
+
+  err = tg3_parse_glb(&roundtrip, &errors, out, out_size, "", 0, &parse_opts);
+  if (err != TG3_OK || roundtrip.buffers_count != 1 ||
+      roundtrip.buffers[0].data.count != 4 ||
+      roundtrip.buffers[0].data.data[0] != 1 ||
+      roundtrip.buffers[0].data.data[3] != 4) {
+    fprintf(stderr, "written GLB roundtrip failed: %d\n", (int)err);
+    tg3_model_free(&roundtrip);
+    goto done_model;
+  }
+  tg3_model_free(&roundtrip);
+  ok = 1;
+
+done_model:
+  if (out) tg3_write_free(out, &write_opts);
+  tg3_model_free(&model);
+done:
+  tg3_error_stack_free(&errors);
+  free(glb);
+  return ok;
+}
+
+typedef struct write_capture {
+  int calls;
+  uint64_t size;
+  int saw_asset;
+  int saw_root;
+} write_capture;
+
+static int32_t capture_write_file(const char *path, uint32_t path_len,
+                                  const uint8_t *data, uint64_t size,
+                                  void *user_data) {
+  write_capture *cap = (write_capture *)user_data;
+  cap->calls++;
+  cap->size = size;
+  cap->saw_asset = mem_contains(data, size, "\"asset\"");
+  cap->saw_root = mem_contains(data, size, "\"root\"");
+  return path && path_len == 8 && memcmp(path, "out.gltf", 8) == 0;
+}
+
+static int check_write_to_file_callback(void) {
+  static const uint8_t json[] =
+      "{\"asset\":{\"version\":\"2.0\"},\"nodes\":[{\"name\":\"root\"}]}";
+  tg3_model model;
+  tg3_error_stack errors;
+  tg3_parse_options parse_opts;
+  tg3_write_options write_opts;
+  tg3_error_code err;
+  write_capture cap;
+  memset(&cap, 0, sizeof(cap));
+  tg3_error_stack_init(&errors);
+  tg3_parse_options_init(&parse_opts);
+  tg3_write_options_init(&write_opts);
+
+  err = tg3_parse(&model, &errors, json, (uint64_t)(sizeof(json) - 1), "", 0,
+                  &parse_opts);
+  if (err != TG3_OK) {
+    fprintf(stderr, "parse before write callback failed: %d\n", (int)err);
+    tg3_error_stack_free(&errors);
+    return 0;
+  }
+  write_opts.fs.write_file = capture_write_file;
+  write_opts.fs.user_data = &cap;
+  err = tg3_write_to_file(&model, &errors, "out.gltf", 8, &write_opts);
+  if (err != TG3_OK || cap.calls != 1 || cap.size == 0 ||
+      !cap.saw_asset || !cap.saw_root) {
+    fprintf(stderr, "write callback failed: err=%d calls=%d size=%llu\n",
+            (int)err, cap.calls, (unsigned long long)cap.size);
+    tg3_model_free(&model);
+    tg3_error_stack_free(&errors);
+    return 0;
+  }
+  tg3_model_free(&model);
+  tg3_error_stack_free(&errors);
+  return 1;
+}
+
+typedef struct read_capture {
+  int calls;
+  int frees;
+} read_capture;
+
+static int32_t memory_read_file(uint8_t **out_data, uint64_t *out_size,
+                                const char *path, uint32_t path_len,
+                                void *user_data) {
+  static const uint8_t json[] =
+      "{\"asset\":{\"version\":\"2.0\"},\"nodes\":[{\"name\":\"from-callback\"}]}";
+  read_capture *cap = (read_capture *)user_data;
+  uint8_t *copy;
+  if (!path || path_len != 15 || memcmp(path, "mem/model.gltf", 15) != 0) return 0;
+  cap->calls++;
+  copy = (uint8_t *)malloc(sizeof(json) - 1);
+  if (!copy) return 0;
+  memcpy(copy, json, sizeof(json) - 1);
+  *out_data = copy;
+  *out_size = (uint64_t)(sizeof(json) - 1);
+  return 1;
+}
+
+static void memory_free_file(uint8_t *data, uint64_t size, void *user_data) {
+  read_capture *cap = (read_capture *)user_data;
+  (void)size;
+  cap->frees++;
+  free(data);
+}
+
+static int check_parse_file_callback(void) {
+  tg3_model model;
+  tg3_error_stack errors;
+  tg3_parse_options opts;
+  tg3_error_code err;
+  read_capture cap;
+  memset(&cap, 0, sizeof(cap));
+  tg3_error_stack_init(&errors);
+  tg3_parse_options_init(&opts);
+  opts.fs.read_file = memory_read_file;
+  opts.fs.free_file = memory_free_file;
+  opts.fs.user_data = &cap;
+  err = tg3_parse_file(&model, &errors, "mem/model.gltf", 15, &opts);
+  if (err != TG3_OK || cap.calls != 1 || cap.frees != 1 ||
+      model.nodes_count != 1 ||
+      !tg3_str_equals_cstr(model.nodes[0].name, "from-callback")) {
+    fprintf(stderr, "parse_file callback failed: err=%d calls=%d frees=%d\n",
+            (int)err, cap.calls, cap.frees);
+    tg3_model_free(&model);
+    tg3_error_stack_free(&errors);
+    return 0;
+  }
+  tg3_model_free(&model);
+  tg3_error_stack_free(&errors);
+  return 1;
+}
+
+typedef struct chunk_capture {
+  int calls;
+  uint64_t size;
+  int saw_asset;
+  int saw_node;
+} chunk_capture;
+
+static int32_t capture_chunk(const uint8_t *data, uint64_t size, void *user_data) {
+  chunk_capture *cap = (chunk_capture *)user_data;
+  cap->calls++;
+  cap->size += size;
+  cap->saw_asset = cap->saw_asset || mem_contains(data, size, "\"asset\"");
+  cap->saw_node = cap->saw_node || mem_contains(data, size, "\"stream-node\"");
+  return 1;
+}
+
+static int check_streaming_writer(void) {
+  tg3_write_options opts;
+  tg3_writer *w;
+  tg3_asset asset;
+  tg3_node node;
+  chunk_capture cap;
+  tg3_error_code err;
+  memset(&asset, 0, sizeof(asset));
+  memset(&node, 0, sizeof(node));
+  memset(&cap, 0, sizeof(cap));
+  tg3_write_options_init(&opts);
+  asset.version.data = "2.0";
+  asset.version.len = 3;
+  node.name.data = "stream-node";
+  node.name.len = 11;
+  node.camera = -1;
+  node.skin = -1;
+  node.mesh = -1;
+  node.light = -1;
+  node.emitter = -1;
+  node.rotation[3] = 1.0;
+  node.scale[0] = 1.0;
+  node.scale[1] = 1.0;
+  node.scale[2] = 1.0;
+  w = tg3_writer_create(capture_chunk, &cap, &opts);
+  if (!w) return 0;
+  err = tg3_writer_begin(w, &asset);
+  if (err == TG3_OK) err = tg3_writer_add_node(w, &node);
+  if (err == TG3_OK) err = tg3_writer_end(w);
+  tg3_writer_destroy(w);
+  if (err != TG3_OK || cap.calls != 1 || cap.size == 0 ||
+      !cap.saw_asset || !cap.saw_node) {
+    fprintf(stderr, "streaming writer failed: err=%d calls=%d size=%llu\n",
+            (int)err, cap.calls, (unsigned long long)cap.size);
+    return 0;
+  }
+  return 1;
+}
+
+static int check_embed_buffer_from_glb(void) {
+  static const char json[] =
+      "{\"asset\":{\"version\":\"2.0\"},\"buffers\":[{\"byteLength\":4}]}";
+  uint32_t json_len = (uint32_t)(sizeof(json) - 1);
+  uint32_t json_padded = (json_len + 3u) & ~3u;
+  uint32_t bin_len = 4;
+  uint32_t total = 12u + 8u + json_padded + 8u + bin_len;
+  uint8_t *glb = (uint8_t *)malloc(total);
+  uint32_t bin_off = 12u + 8u + json_padded + 8u;
+  tg3_model model;
+  tg3_error_stack errors;
+  tg3_parse_options parse_opts;
+  tg3_write_options write_opts;
+  tg3_error_code err;
+  uint8_t *out = NULL;
+  uint64_t out_size = 0;
+  int ok = 0;
+
+  if (!glb) return 0;
+  memset(glb, ' ', total);
+  memcpy(glb, "glTF", 4);
+  write_u32le(glb + 4, 2u);
+  write_u32le(glb + 8, total);
+  write_u32le(glb + 12, json_padded);
+  write_u32le(glb + 16, 0x4E4F534Au);
+  memcpy(glb + 20, json, json_len);
+  write_u32le(glb + 20 + json_padded, bin_len);
+  write_u32le(glb + 24 + json_padded, 0x004E4942u);
+  glb[bin_off + 0] = 1;
+  glb[bin_off + 1] = 2;
+  glb[bin_off + 2] = 3;
+  glb[bin_off + 3] = 4;
+
+  tg3_error_stack_init(&errors);
+  tg3_parse_options_init(&parse_opts);
+  parse_opts.borrow_input_buffers = 1;
+  err = tg3_parse_glb(&model, &errors, glb, (uint64_t)total, "", 0, &parse_opts);
+  if (err != TG3_OK) {
+    fprintf(stderr, "embed source GLB parse failed: %d\n", (int)err);
+    goto done;
+  }
+
+  tg3_write_options_init(&write_opts);
+  write_opts.pretty_print = 0;
+  write_opts.embed_buffers = 1;
+  err = tg3_write_to_memory(&model, &errors, &out, &out_size, &write_opts);
+  if (err != TG3_OK || !out ||
+      !mem_contains(out, out_size, "\"uri\":\"data:application/octet-stream;base64,AQIDBA==\"")) {
+    fprintf(stderr, "embed_buffers JSON missing expected data URI: err=%d\n", (int)err);
+    goto done_model;
+  }
+  ok = 1;
+
+done_model:
+  if (out) tg3_write_free(out, &write_opts);
+  tg3_model_free(&model);
+done:
+  tg3_error_stack_free(&errors);
+  free(glb);
+  return ok;
+}
+
+static int check_serialize_defaults(void) {
+  static const uint8_t json[] =
+      "{\"asset\":{\"version\":\"2.0\"},\"nodes\":[{\"name\":\"n\"}],"
+      "\"materials\":[{}]}";
+  tg3_model model;
+  tg3_error_stack errors;
+  tg3_parse_options parse_opts;
+  tg3_write_options write_opts;
+  tg3_error_code err;
+  uint8_t *out = NULL;
+  uint64_t out_size = 0;
+  int ok;
+
+  tg3_error_stack_init(&errors);
+  tg3_parse_options_init(&parse_opts);
+  tg3_write_options_init(&write_opts);
+  write_opts.pretty_print = 0;
+  write_opts.serialize_defaults = 1;
+  err = tg3_parse(&model, &errors, json, (uint64_t)(sizeof(json) - 1), "", 0,
+                  &parse_opts);
+  if (err != TG3_OK) {
+    fprintf(stderr, "serialize-defaults parse failed: %d\n", (int)err);
+    tg3_error_stack_free(&errors);
+    return 0;
+  }
+  err = tg3_write_to_memory(&model, &errors, &out, &out_size, &write_opts);
+  ok = (err == TG3_OK && out &&
+        mem_contains(out, out_size, "\"translation\"") &&
+        mem_contains(out, out_size, "\"rotation\"") &&
+        mem_contains(out, out_size, "\"scale\"") &&
+        mem_contains(out, out_size, "\"alphaCutoff\"") &&
+        mem_contains(out, out_size, "\"doubleSided\""));
+  if (!ok) fprintf(stderr, "serialize_defaults missing expected default fields\n");
+  if (out) tg3_write_free(out, &write_opts);
+  tg3_model_free(&model);
+  tg3_error_stack_free(&errors);
+  return ok;
+}
+
+static int check_parse_float32_model(void) {
+  static const uint8_t json[] =
+      "{\"asset\":{\"version\":\"2.0\"},"
+      "\"accessors\":[{\"componentType\":5126,\"count\":1,\"type\":\"SCALAR\","
+      "\"min\":[0.10000000149011612],\"max\":[0.10000000149011612]}]}";
+  tg3_model model;
+  tg3_error_stack errors;
+  tg3_parse_options opts;
+  tg3_error_code err;
+  double expected = (double)(float)0.10000000149011612;
+  int ok;
+
+  tg3_error_stack_init(&errors);
+  tg3_parse_options_init(&opts);
+  opts.parse_float32 = 1;
+  err = tg3_parse(&model, &errors, json, (uint64_t)(sizeof(json) - 1), "", 0, &opts);
+  ok = (err == TG3_OK && model.accessors_count == 1 &&
+        model.accessors[0].min_values_count == 1 &&
+        model.accessors[0].max_values_count == 1 &&
+        model.accessors[0].min_values[0] == expected &&
+        model.accessors[0].max_values[0] == expected);
+  if (!ok) fprintf(stderr, "model parse_float32 failed: err=%d\n", (int)err);
+  tg3_model_free(&model);
+  tg3_error_stack_free(&errors);
+  return ok;
+}
+
+typedef struct parse_stream_capture {
+  int assets;
+  int nodes;
+  int scenes;
+  int saw_stream_node;
+} parse_stream_capture;
+
+static tg3_stream_action stream_asset_cb(const tg3_asset *a, void *ud) {
+  parse_stream_capture *cap = (parse_stream_capture *)ud;
+  cap->assets++;
+  (void)a;
+  return TG3_STREAM_CONTINUE;
+}
+
+static tg3_stream_action stream_node_cb(const tg3_node *n, int32_t idx, void *ud) {
+  parse_stream_capture *cap = (parse_stream_capture *)ud;
+  (void)idx;
+  cap->nodes++;
+  if (tg3_str_equals_cstr(n->name, "streamed")) cap->saw_stream_node = 1;
+  return TG3_STREAM_CONTINUE;
+}
+
+static tg3_stream_action stream_scene_cb(const tg3_scene *s, int32_t idx, void *ud) {
+  parse_stream_capture *cap = (parse_stream_capture *)ud;
+  (void)s;
+  (void)idx;
+  cap->scenes++;
+  return TG3_STREAM_CONTINUE;
+}
+
+static tg3_stream_action aborting_node_cb(const tg3_node *n, int32_t idx, void *ud) {
+  (void)n;
+  (void)idx;
+  (void)ud;
+  return TG3_STREAM_ABORT;
+}
+
+static int check_parse_stream_callbacks(void) {
+  static const uint8_t json[] =
+      "{\"asset\":{\"version\":\"2.0\"},\"scene\":0,"
+      "\"scenes\":[{\"nodes\":[0]}],\"nodes\":[{\"name\":\"streamed\"}]}";
+  tg3_model model;
+  tg3_error_stack errors;
+  tg3_parse_options opts;
+  tg3_stream_callbacks stream;
+  parse_stream_capture cap;
+  tg3_error_code err;
+
+  memset(&stream, 0, sizeof(stream));
+  memset(&cap, 0, sizeof(cap));
+  stream.on_asset = stream_asset_cb;
+  stream.on_node = stream_node_cb;
+  stream.on_scene = stream_scene_cb;
+  stream.user_data = &cap;
+  tg3_error_stack_init(&errors);
+  tg3_parse_options_init(&opts);
+  opts.stream = &stream;
+  err = tg3_parse(&model, &errors, json, (uint64_t)(sizeof(json) - 1), "", 0, &opts);
+  if (err != TG3_OK || cap.assets != 1 || cap.nodes != 1 || cap.scenes != 1 ||
+      !cap.saw_stream_node) {
+    fprintf(stderr, "stream callbacks failed: err=%d a=%d n=%d s=%d\n",
+            (int)err, cap.assets, cap.nodes, cap.scenes);
+    tg3_model_free(&model);
+    tg3_error_stack_free(&errors);
+    return 0;
+  }
+  tg3_model_free(&model);
+  tg3_error_stack_free(&errors);
+
+  memset(&stream, 0, sizeof(stream));
+  stream.on_node = aborting_node_cb;
+  tg3_error_stack_init(&errors);
+  tg3_parse_options_init(&opts);
+  opts.stream = &stream;
+  err = tg3_parse(&model, &errors, json, (uint64_t)(sizeof(json) - 1), "", 0, &opts);
+  if (err != TG3_ERR_STREAM_ABORTED) {
+    fprintf(stderr, "stream abort returned %d\n", (int)err);
+    tg3_model_free(&model);
+    tg3_error_stack_free(&errors);
+    return 0;
+  }
+  tg3_model_free(&model);
+  tg3_error_stack_free(&errors);
+  return 1;
+}
+
+static int check_store_original_json(void) {
+  static const uint8_t json[] =
+      "{\"asset\":{\"version\":\"2.0\"},\"extras\":{\"answer\":42},"
+      "\"extensions\":{\"VENDOR_test\":{\"enabled\":true}}}";
+  tg3_model model;
+  tg3_error_stack errors;
+  tg3_parse_options opts;
+  tg3_error_code err;
+  int ok;
+  tg3_error_stack_init(&errors);
+  tg3_parse_options_init(&opts);
+  opts.store_original_json = 1;
+  err = tg3_parse(&model, &errors, json, (uint64_t)(sizeof(json) - 1), "", 0, &opts);
+  ok = (err == TG3_OK &&
+        model.ext.extras && model.ext.extras->type == TG3_VALUE_OBJECT &&
+        model.ext.extras_json.data && model.ext.extras_json.len > 0 &&
+        model.ext.extensions_count == 1 &&
+        model.ext.extensions_json.data && model.ext.extensions_json.len > 0);
+  if (!ok) fprintf(stderr, "store_original_json failed: err=%d\n", (int)err);
+  tg3_model_free(&model);
+  tg3_error_stack_free(&errors);
+  return ok;
+}
+
+static int check_glb_header_errors(void) {
+  uint8_t glb[28];
+  tg3_model model;
+  tg3_error_stack errors;
+  tg3_parse_options opts;
+  tg3_error_code err;
+  int ok = 1;
+
+  tg3_parse_options_init(&opts);
+  tg3_error_stack_init(&errors);
+  memset(glb, 0, sizeof(glb));
+  memcpy(glb, "BAD!", 4);
+  write_u32le(glb + 4, 2u);
+  write_u32le(glb + 8, 28u);
+  err = tg3_parse_glb(&model, &errors, glb, sizeof(glb), "", 0, &opts);
+  ok = ok && (err == TG3_ERR_GLB_INVALID_MAGIC);
+  tg3_model_free(&model);
+  tg3_error_stack_free(&errors);
+
+  tg3_error_stack_init(&errors);
+  memset(glb, 0, sizeof(glb));
+  memcpy(glb, "glTF", 4);
+  write_u32le(glb + 4, 1u);
+  write_u32le(glb + 8, 28u);
+  err = tg3_parse_glb(&model, &errors, glb, sizeof(glb), "", 0, &opts);
+  ok = ok && (err == TG3_ERR_GLB_INVALID_VERSION);
+  tg3_model_free(&model);
+  tg3_error_stack_free(&errors);
+
+  tg3_error_stack_init(&errors);
+  memset(glb, 0, sizeof(glb));
+  memcpy(glb, "glTF", 4);
+  write_u32le(glb + 4, 2u);
+  write_u32le(glb + 8, 4096u);
+  err = tg3_parse_glb(&model, &errors, glb, sizeof(glb), "", 0, &opts);
+  ok = ok && (err == TG3_ERR_GLB_SIZE_MISMATCH);
+  tg3_model_free(&model);
+  tg3_error_stack_free(&errors);
+
+  if (!ok) fprintf(stderr, "GLB header error coverage failed\n");
+  return ok;
+}
+
 static int check_parse_file_failure_initializes_model(void) {
   tg3_model model;
   tg3_error_stack errors;
@@ -928,6 +1461,36 @@ int main(int argc, char **argv) {
   if (!check_minimal_write_roundtrip()) {
     return 1;
   }
+  if (!check_binary_write_roundtrip()) {
+    return 1;
+  }
+  if (!check_embed_buffer_from_glb()) {
+    return 1;
+  }
+  if (!check_serialize_defaults()) {
+    return 1;
+  }
+  if (!check_parse_float32_model()) {
+    return 1;
+  }
+  if (!check_write_to_file_callback()) {
+    return 1;
+  }
+  if (!check_parse_file_callback()) {
+    return 1;
+  }
+  if (!check_streaming_writer()) {
+    return 1;
+  }
+  if (!check_parse_stream_callbacks()) {
+    return 1;
+  }
+  if (!check_store_original_json()) {
+    return 1;
+  }
+  if (!check_glb_header_errors()) {
+    return 1;
+  }
   if (!check_parse_file_failure_initializes_model()) {
     return 1;
   }
diff --git a/tests/tester_v3_freestanding.c b/tests/tester_v3_freestanding.c
new file mode 100644
index 0000000..b68dc73
--- /dev/null
+++ b/tests/tester_v3_freestanding.c
@@ -0,0 +1,75 @@
+#include <stddef.h>
+#include <stdint.h>
+
+static union {
+  uint64_t align;
+  unsigned char bytes[512 * 1024];
+} test_heap;
+static size_t test_heap_used;
+
+static void *test_malloc(size_t size) {
+  size_t total = (size + sizeof(size_t) + 7u) & ~(size_t)7u;
+  if (test_heap_used + total > sizeof(test_heap.bytes)) return 0;
+  {
+    unsigned char *base = test_heap.bytes + test_heap_used;
+    *((size_t *)base) = size;
+    test_heap_used += total;
+    return base + sizeof(size_t);
+  }
+}
+
+static void *test_realloc(void *ptr, size_t size) {
+  unsigned char *old_base;
+  size_t old_size;
+  unsigned char *new_ptr;
+  size_t n;
+  size_t i;
+  if (!ptr) return test_malloc(size);
+  old_base = (unsigned char *)ptr - sizeof(size_t);
+  old_size = *((size_t *)old_base);
+  new_ptr = (unsigned char *)test_malloc(size);
+  if (!new_ptr) return 0;
+  n = old_size < size ? old_size : size;
+  for (i = 0; i < n; ++i) new_ptr[i] = ((unsigned char *)ptr)[i];
+  return new_ptr;
+}
+
+static void test_free(void *ptr) {
+  (void)ptr;
+}
+
+#define TINYGLTF3_NO_STDLIB
+#define TINYGLTF3_MALLOC(sz) test_malloc(sz)
+#define TINYGLTF3_REALLOC(ptr, sz) test_realloc((ptr), (sz))
+#define TINYGLTF3_FREE(ptr) test_free(ptr)
+#define TINYGLTF3_IMPLEMENTATION
+#include "tiny_gltf_v3.h"
+
+static int streq(tg3_str s, const char *lit, uint32_t len) {
+  uint32_t i;
+  if (!s.data || s.len != len) return 0;
+  for (i = 0; i < len; ++i) {
+    if (s.data[i] != lit[i]) return 0;
+  }
+  return 1;
+}
+
+int main(void) {
+  static const uint8_t json[] =
+      "{\"asset\":{\"version\":\"2.0\"},\"nodes\":[{\"name\":\"free\"}]}";
+  tg3_model model;
+  tg3_error_stack errors;
+  tg3_parse_options opts;
+  tg3_error_code err;
+
+  tg3_error_stack_init(&errors);
+  tg3_parse_options_init(&opts);
+  err = tg3_parse_auto(&model, &errors, json, (uint64_t)(sizeof(json) - 1),
+                       "", 0, &opts);
+  if (err != TG3_OK) return 1;
+  if (model.nodes_count != 1) return 3;
+  if (!streq(model.nodes[0].name, "free", 4)) return 4;
+  tg3_model_free(&model);
+  tg3_error_stack_free(&errors);
+  return 0;
+}
diff --git a/tests/tester_v3_json_c.c b/tests/tester_v3_json_c.c
new file mode 100644
index 0000000..243aa50
--- /dev/null
+++ b/tests/tester_v3_json_c.c
@@ -0,0 +1,165 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#define TINYGLTF_JSON_C_IMPLEMENTATION
+#include "tinygltf_json_c.h"
+
+static uint64_t dbl_bits(double v) {
+  uint64_t bits;
+  memcpy(&bits, &v, sizeof(bits));
+  return bits;
+}
+
+static double dbl_from_bits(uint64_t bits) {
+  double v;
+  memcpy(&v, &bits, sizeof(v));
+  return v;
+}
+
+static int check_stringify(const char *json, const char *expected) {
+  tg3json_value v;
+  const char *err = NULL;
+  char *out;
+  size_t out_len = 0;
+  int ok = 1;
+  if (!tg3json_parse(json, json + strlen(json), 128, &v, &err)) {
+    fprintf(stderr, "parse failed for %s at %td\n", json, err ? err - json : -1);
+    return 0;
+  }
+  out = tg3json_stringify(&v, &out_len);
+  if (!out || strcmp(out, expected) != 0) {
+    fprintf(stderr, "stringify(%s) = %s, expected %s\n",
+            json, out ? out : "(null)", expected);
+    ok = 0;
+  }
+  if (out) TINYGLTF_JSON_FREE(out);
+  tg3json_value_free(&v);
+  return ok;
+}
+
+static int check_parse_rejects(const char *json) {
+  tg3json_value v;
+  const char *err = NULL;
+  if (tg3json_parse(json, json + strlen(json), 128, &v, &err)) {
+    fprintf(stderr, "parse unexpectedly accepted %s\n", json);
+    tg3json_value_free(&v);
+    return 0;
+  }
+  return 1;
+}
+
+static int check_roundtrip(const char *json) {
+  tg3json_value a;
+  tg3json_value b;
+  const char *err = NULL;
+  char *out;
+  size_t out_len = 0;
+  int ok = 1;
+  if (!tg3json_parse(json, json + strlen(json), 128, &a, &err)) return 0;
+  out = tg3json_stringify(&a, &out_len);
+  if (!out || !tg3json_parse(out, out + out_len, 128, &b, &err)) {
+    ok = 0;
+  } else if (a.type != TG3JSON_REAL ||
+             !((b.type == TG3JSON_REAL && dbl_bits(a.u.real) == dbl_bits(b.u.real)) ||
+               (b.type == TG3JSON_INT && dbl_bits(a.u.real) == dbl_bits((double)b.u.integer)))) {
+    fprintf(stderr, "roundtrip changed bits: %s -> %s\n", json, out);
+    ok = 0;
+  }
+  if (out) TINYGLTF_JSON_FREE(out);
+  tg3json_value_free(&a);
+  tg3json_value_free(&b);
+  return ok;
+}
+
+static int check_parse_bits(const char *json, uint64_t expected_bits) {
+  tg3json_value v;
+  const char *err = NULL;
+  if (!tg3json_parse(json, json + strlen(json), 128, &v, &err)) {
+    fprintf(stderr, "parse failed for %s at %td\n", json, err ? err - json : -1);
+    return 0;
+  }
+  if (v.type != TG3JSON_REAL || dbl_bits(v.u.real) != expected_bits) {
+    fprintf(stderr, "parse bits mismatch: %s -> 0x%llx, expected 0x%llx\n",
+            json, (unsigned long long)(v.type == TG3JSON_REAL ? dbl_bits(v.u.real) : 0),
+            (unsigned long long)expected_bits);
+    tg3json_value_free(&v);
+    return 0;
+  }
+  tg3json_value_free(&v);
+  return 1;
+}
+
+static int check_parse_float32(void) {
+  static const char json[] = "0.10000000149011612";
+  tg3json_parse_options opts;
+  tg3json_value v;
+  const char *err = NULL;
+  double expected = (double)(float)0.10000000149011612;
+  memset(&opts, 0, sizeof(opts));
+  opts.parse_float32 = 1;
+  if (!tg3json_parse_n_opts(json, strlen(json), &opts, &v, &err)) {
+    fprintf(stderr, "parse_float32 parse failed\n");
+    return 0;
+  }
+  if (v.type != TG3JSON_REAL || dbl_bits(v.u.real) != dbl_bits(expected)) {
+    fprintf(stderr, "parse_float32 did not round through float\n");
+    tg3json_value_free(&v);
+    return 0;
+  }
+  tg3json_value_free(&v);
+  return 1;
+}
+
+static int check_nonfinite_stringifies_to_null(void) {
+  tg3json_value v;
+  char *out;
+  size_t len = 0;
+  int ok;
+  tg3json_value_init_real(&v, dbl_from_bits(0x7ff0000000000000ULL));
+  out = tg3json_stringify(&v, &len);
+  ok = out && strcmp(out, "null") == 0;
+  if (!ok) fprintf(stderr, "inf stringify = %s\n", out ? out : "(null)");
+  if (out) TINYGLTF_JSON_FREE(out);
+  tg3json_value_free(&v);
+  if (!ok) return 0;
+
+  tg3json_value_init_real(&v, dbl_from_bits(0x7ff8000000000001ULL));
+  out = tg3json_stringify(&v, &len);
+  ok = out && strcmp(out, "null") == 0;
+  if (!ok) fprintf(stderr, "nan stringify = %s\n", out ? out : "(null)");
+  if (out) TINYGLTF_JSON_FREE(out);
+  tg3json_value_free(&v);
+  return ok;
+}
+
+int main(void) {
+  int ok = 1;
+  ok = check_stringify("1.0", "1") && ok;
+  ok = check_stringify("-1.0", "-1") && ok;
+  ok = check_stringify("0.1", "0.1") && ok;
+  ok = check_stringify("0.0001", "0.0001") && ok;
+  ok = check_stringify("0.00001", "1e-5") && ok;
+  ok = check_stringify("1000000000000000.0", "1000000000000000") && ok;
+  ok = check_stringify("10000000000000000.0", "1e16") && ok;
+  ok = check_roundtrip("1.2345678901234567") && ok;
+  ok = check_roundtrip("2.2250738585072014e-308") && ok;
+  ok = check_roundtrip("5e-324") && ok;
+  ok = check_roundtrip("-5e-324") && ok;
+  ok = check_roundtrip("9007199254740993.0") && ok;
+  ok = check_parse_bits("1.23456789012345678901", 0x3ff3c0ca428c59fbULL) && ok;
+  ok = check_parse_bits("1.234567890123456789012345678901234567890e-100",
+                        0x2b31482fe620c5d2ULL) && ok;
+  ok = check_parse_bits("1.7976931348623157e308", 0x7fefffffffffffffULL) && ok;
+  ok = check_parse_float32() && ok;
+  ok = check_nonfinite_stringifies_to_null() && ok;
+  ok = check_parse_rejects("+1") && ok;
+  ok = check_parse_rejects("01") && ok;
+  ok = check_parse_rejects("1.") && ok;
+  ok = check_parse_rejects("1e") && ok;
+  ok = check_parse_rejects("1e400") && ok;
+  ok = check_parse_rejects("-1e400") && ok;
+  ok = check_parse_rejects("1.7976931348623159e308") && ok;
+  ok = check_parse_rejects("[1,]") && ok;
+  return ok ? 0 : 1;
+}
diff --git a/tiny_gltf_v3.c b/tiny_gltf_v3.c
index 5120890..d8680df 100644
--- a/tiny_gltf_v3.c
+++ b/tiny_gltf_v3.c
@@ -1,14 +1,136 @@
 #ifndef TINYGLTF3_SOURCE_INCLUDED_FROM_HEADER
 #include "tiny_gltf_v3.h"
 #endif
+#ifdef TINYGLTF3_NO_STDLIB
+#ifndef TINYGLTF_JSON_NO_STDLIB
+#define TINYGLTF_JSON_NO_STDLIB
+#endif
+#endif
+#ifndef TINYGLTF_JSON_MALLOC
+#define TINYGLTF_JSON_MALLOC(sz) TINYGLTF3_MALLOC(sz)
+#endif
+#ifndef TINYGLTF_JSON_REALLOC
+#define TINYGLTF_JSON_REALLOC(ptr, sz) TINYGLTF3_REALLOC((ptr), (sz))
+#endif
+#ifndef TINYGLTF_JSON_FREE
+#define TINYGLTF_JSON_FREE(ptr) TINYGLTF3_FREE(ptr)
+#endif
 #define TINYGLTF_JSON_C_IMPLEMENTATION
 #include "tinygltf_json_c.h"
 
 #include <inttypes.h>
+#ifndef TINYGLTF3_NO_STDLIB
 #include <math.h>
 #include <stdlib.h>
-#include <stdio.h>
 #include <string.h>
+#include <stdio.h>
+#endif
+
+static void *tg3__memcpy(void *dst, const void *src, size_t size) {
+#ifndef TINYGLTF3_NO_STDLIB
+    return memcpy(dst, src, size);
+#else
+    unsigned char *d = (unsigned char *)dst;
+    const unsigned char *s = (const unsigned char *)src;
+    while (size--) *d++ = *s++;
+    return dst;
+#endif
+}
+
+static void *tg3__memset(void *dst, int value, size_t size) {
+#ifndef TINYGLTF3_NO_STDLIB
+    return memset(dst, value, size);
+#else
+    unsigned char *d = (unsigned char *)dst;
+    while (size--) *d++ = (unsigned char)value;
+    return dst;
+#endif
+}
+
+static int tg3__memcmp(const void *a, const void *b, size_t size) {
+#ifndef TINYGLTF3_NO_STDLIB
+    return memcmp(a, b, size);
+#else
+    const unsigned char *pa = (const unsigned char *)a;
+    const unsigned char *pb = (const unsigned char *)b;
+    while (size--) {
+        if (*pa != *pb) return (int)*pa - (int)*pb;
+        ++pa;
+        ++pb;
+    }
+    return 0;
+#endif
+}
+
+static size_t tg3__strlen(const char *s) {
+#ifndef TINYGLTF3_NO_STDLIB
+    return strlen(s);
+#else
+    const char *p = s;
+    while (*p) ++p;
+    return (size_t)(p - s);
+#endif
+}
+
+static void *tg3__memchr(const void *s, int c, size_t size) {
+#ifndef TINYGLTF3_NO_STDLIB
+    return (void *)memchr(s, c, size);
+#else
+    const unsigned char *p = (const unsigned char *)s;
+    unsigned char ch = (unsigned char)c;
+    while (size--) {
+        if (*p == ch) return (void *)p;
+        ++p;
+    }
+    return NULL;
+#endif
+}
+
+static int tg3__isfinite(double v) {
+    uint64_t bits = 0;
+    tg3__memcpy(&bits, &v, sizeof(bits));
+    return (bits & 0x7ff0000000000000ULL) != 0x7ff0000000000000ULL;
+}
+
+static double tg3__fabs(double v) {
+    uint64_t bits = 0;
+    tg3__memcpy(&bits, &v, sizeof(bits));
+    bits &= 0x7fffffffffffffffULL;
+    tg3__memcpy(&v, &bits, sizeof(v));
+    return v;
+}
+
+static int tg3__vsnprintf(char *buf, size_t size, const char *fmt, va_list ap) {
+#ifndef TINYGLTF3_NO_STDLIB
+    return vsnprintf(buf, size, fmt, ap);
+#else
+    size_t i = 0;
+    (void)ap;
+    if (size == 0) return 0;
+    while (fmt[i] && i + 1u < size) {
+        buf[i] = fmt[i];
+        ++i;
+    }
+    buf[i] = '\0';
+    return (int)i;
+#endif
+}
+
+#ifndef TINYGLTF3_MEMCPY
+#define TINYGLTF3_MEMCPY(dst, src, size) tg3__memcpy((dst), (src), (size))
+#endif
+#ifndef TINYGLTF3_MEMSET
+#define TINYGLTF3_MEMSET(dst, value, size) tg3__memset((dst), (value), (size))
+#endif
+#ifndef TINYGLTF3_MEMCMP
+#define TINYGLTF3_MEMCMP(a, b, size) tg3__memcmp((a), (b), (size))
+#endif
+#ifndef TINYGLTF3_STRLEN
+#define TINYGLTF3_STRLEN(s) tg3__strlen((s))
+#endif
+#ifndef TINYGLTF3_MEMCHR
+#define TINYGLTF3_MEMCHR(s, c, size) tg3__memchr((s), (c), (size))
+#endif
 
 #define TG3__ARENA_DEFAULT_BLOCK_SIZE (256u * 1024u)
 #define TG3__ARENA_ALIGNMENT 8u
@@ -52,20 +174,23 @@ struct tg3_writer {
 };
 
 static void *tg3__default_alloc(size_t size, void *ud) {
+    (void)size;
     (void)ud;
-    return malloc(size);
+    return TINYGLTF3_MALLOC(size);
 }
 
 static void *tg3__default_realloc(void *ptr, size_t old_size, size_t new_size, void *ud) {
+    (void)ptr;
     (void)old_size;
+    (void)new_size;
     (void)ud;
-    return realloc(ptr, new_size);
+    return TINYGLTF3_REALLOC(ptr, new_size);
 }
 
 static void tg3__default_free(void *ptr, size_t size, void *ud) {
     (void)size;
     (void)ud;
-    free(ptr);
+    TINYGLTF3_FREE(ptr);
 }
 
 static tg3_arena *tg3__arena_create(const tg3_memory_config *config) {
@@ -82,7 +207,7 @@ static tg3_arena *tg3__arena_create(const tg3_memory_config *config) {
 
     arena = (tg3_arena *)alloc.alloc(sizeof(tg3_arena), alloc.user_data);
     if (!arena) return NULL;
-    memset(arena, 0, sizeof(*arena));
+    TINYGLTF3_MEMSET(arena, 0, sizeof(*arena));
     arena->alloc = alloc;
     arena->block_size = (config && config->arena_block_size > 0)
                             ? (size_t)config->arena_block_size
@@ -140,7 +265,7 @@ static char *tg3__arena_strdup(tg3_arena *arena, const char *s, size_t len) {
     if (!s) return NULL;
     dst = (char *)tg3__arena_alloc(arena, len + 1);
     if (!dst) return NULL;
-    if (len > 0) memcpy(dst, s, len);
+    if (len > 0) TINYGLTF3_MEMCPY(dst, s, len);
     dst[len] = '\0';
     return dst;
 }
@@ -175,7 +300,7 @@ static void tg3__error_push(tg3_error_stack *es, tg3_severity sev,
     if (!es) return;
     if (es->count >= es->capacity) {
         new_cap = es->capacity ? es->capacity * 2u : 16u;
-        new_entries = (tg3_error_entry *)realloc(es->entries, new_cap * sizeof(tg3_error_entry));
+        new_entries = (tg3_error_entry *)TINYGLTF3_REALLOC(es->entries, new_cap * sizeof(tg3_error_entry));
         if (!new_entries) return;
         es->entries = new_entries;
         es->capacity = new_cap;
@@ -198,7 +323,7 @@ static void tg3__error_pushf(tg3_error_stack *es, tg3_arena *arena,
     const char *msg = buf;
     if (!es) return;
     va_start(ap, fmt);
-    n = vsnprintf(buf, sizeof(buf), fmt, ap);
+    n = tg3__vsnprintf(buf, sizeof(buf), fmt, ap);
     va_end(ap);
     if (n < 0) n = 0;
     if ((size_t)n >= sizeof(buf)) n = (int)(sizeof(buf) - 1u);
@@ -215,16 +340,16 @@ TINYGLTF3_API const tg3_error_entry *tg3_errors_get(const tg3_error_stack *es, u
     if (!es || index >= es->count) return NULL;
     return &es->entries[index];
 }
-TINYGLTF3_API void tg3_error_stack_init(tg3_error_stack *es) { if (es) memset(es, 0, sizeof(*es)); }
+TINYGLTF3_API void tg3_error_stack_init(tg3_error_stack *es) { if (es) TINYGLTF3_MEMSET(es, 0, sizeof(*es)); }
 TINYGLTF3_API void tg3_error_stack_free(tg3_error_stack *es) {
     if (!es) return;
-    free(es->entries);
-    memset(es, 0, sizeof(*es));
+    TINYGLTF3_FREE(es->entries);
+    TINYGLTF3_MEMSET(es, 0, sizeof(*es));
 }
 
 TINYGLTF3_API void tg3_parse_options_init(tg3_parse_options *options) {
     if (!options) return;
-    memset(options, 0, sizeof(*options));
+    TINYGLTF3_MEMSET(options, 0, sizeof(*options));
     options->required_sections = TG3_REQUIRE_VERSION;
     options->strictness = TG3_PERMISSIVE;
     options->memory.memory_budget = TINYGLTF3_MAX_MEMORY_BYTES;
@@ -235,7 +360,7 @@ TINYGLTF3_API void tg3_parse_options_init(tg3_parse_options *options) {
 
 TINYGLTF3_API void tg3_write_options_init(tg3_write_options *options) {
     if (!options) return;
-    memset(options, 0, sizeof(*options));
+    TINYGLTF3_MEMSET(options, 0, sizeof(*options));
     options->pretty_print = 1;
     options->memory.memory_budget = TINYGLTF3_MAX_MEMORY_BYTES;
     options->memory.arena_block_size = TG3__ARENA_DEFAULT_BLOCK_SIZE;
@@ -281,16 +406,16 @@ TINYGLTF3_API int32_t tg3_accessor_byte_stride(const tg3_accessor *accessor, con
 TINYGLTF3_API int32_t tg3_str_equals(tg3_str a, tg3_str b) {
     if (a.len != b.len) return 0;
     if (a.len == 0) return 1;
-    return memcmp(a.data, b.data, a.len) == 0 ? 1 : 0;
+    return TINYGLTF3_MEMCMP(a.data, b.data, a.len) == 0 ? 1 : 0;
 }
 
 TINYGLTF3_API int32_t tg3_str_equals_cstr(tg3_str a, const char *b) {
     uint32_t blen;
     if (!b) return a.len == 0 ? 1 : 0;
-    blen = (uint32_t)strlen(b);
+    blen = (uint32_t)TINYGLTF3_STRLEN(b);
     if (a.len != blen) return 0;
     if (a.len == 0) return 1;
-    return memcmp(a.data, b, a.len) == 0 ? 1 : 0;
+    return TINYGLTF3_MEMCMP(a.data, b, a.len) == 0 ? 1 : 0;
 }
 
 static int tg3__b64_decode_char(unsigned char c) {
@@ -335,7 +460,7 @@ static uint8_t *tg3__b64_decode(const char *input, size_t input_len, size_t *out
 }
 
 TINYGLTF3_API int32_t tg3_is_data_uri(const char *uri, uint32_t len) {
-    return (uri && len >= 5u && memcmp(uri, "data:", 5) == 0) ? 1 : 0;
+    return (uri && len >= 5u && TINYGLTF3_MEMCMP(uri, "data:", 5) == 0) ? 1 : 0;
 }
 
 typedef struct tg3__data_uri_result {
@@ -349,7 +474,7 @@ static int tg3__parse_data_uri(const char *uri, uint32_t uri_len, tg3__data_uri_
     const char *end;
     const char *semi;
     size_t mime_len;
-    if (!uri || uri_len < 5u || memcmp(uri, "data:", 5) != 0) return 0;
+    if (!uri || uri_len < 5u || TINYGLTF3_MEMCMP(uri, "data:", 5) != 0) return 0;
     p = uri + 5;
     end = uri + uri_len;
     semi = p;
@@ -357,10 +482,10 @@ static int tg3__parse_data_uri(const char *uri, uint32_t uri_len, tg3__data_uri_
     if (semi >= end) return 0;
     mime_len = (size_t)(semi - p);
     if (mime_len >= sizeof(result->mime_type)) mime_len = sizeof(result->mime_type) - 1u;
-    memcpy(result->mime_type, p, mime_len);
+    TINYGLTF3_MEMCPY(result->mime_type, p, mime_len);
     result->mime_type[mime_len] = '\0';
     p = semi + 1;
-    if ((size_t)(end - p) < 7u || memcmp(p, "base64,", 7) != 0) return 0;
+    if ((size_t)(end - p) < 7u || TINYGLTF3_MEMCMP(p, "base64,", 7) != 0) return 0;
     p += 7;
     result->data_start = p;
     result->data_len = (size_t)(end - p);
@@ -376,15 +501,15 @@ static uint8_t *tg3__decode_data_uri(tg3_arena *arena, const char *uri, uint32_t
         return NULL;
     }
     if (out_mime && out_mime_cap > 0) {
-        mlen = strlen(dr.mime_type);
+        mlen = TINYGLTF3_STRLEN(dr.mime_type);
         if (mlen >= out_mime_cap) mlen = out_mime_cap - 1u;
-        memcpy(out_mime, dr.mime_type, mlen);
+        TINYGLTF3_MEMCPY(out_mime, dr.mime_type, mlen);
         out_mime[mlen] = '\0';
     }
     return tg3__b64_decode(dr.data_start, dr.data_len, out_len, arena);
 }
 
-#ifdef TINYGLTF3_ENABLE_FS
+#if defined(TINYGLTF3_ENABLE_FS) && !defined(TINYGLTF3_NO_STDLIB)
 static int32_t tg3__fs_file_exists(const char *path, uint32_t path_len, void *ud) {
     FILE *fp;
     (void)path_len; (void)ud;
@@ -409,18 +534,18 @@ static int32_t tg3__fs_read_file(uint8_t **out_data, uint64_t *out_size,
     size = ftell(fp);
     if (size < 0) { fclose(fp); return 0; }
     if (fseek(fp, 0, SEEK_SET) != 0) { fclose(fp); return 0; }
-    data = (uint8_t *)malloc((size_t)size);
+    data = (uint8_t *)TINYGLTF3_MALLOC((size_t)size);
     if (!data) { fclose(fp); return 0; }
     nread = fread(data, 1, (size_t)size, fp);
     fclose(fp);
-    if (nread != (size_t)size) { free(data); return 0; }
+    if (nread != (size_t)size) { TINYGLTF3_FREE(data); return 0; }
     *out_data = data;
     *out_size = (uint64_t)size;
     return 1;
 }
 
 static void tg3__fs_free_file(uint8_t *data, uint64_t size, void *ud) {
-    (void)size; (void)ud; free(data);
+    (void)size; (void)ud; TINYGLTF3_FREE(data);
 }
 
 static int32_t tg3__fs_write_file(const char *path, uint32_t path_len,
@@ -444,7 +569,7 @@ static void tg3__set_default_fs(tg3_fs_callbacks *fs) {
 #endif
 
 static void tg3__model_init(tg3_model *model) {
-    memset(model, 0, sizeof(*model));
+    TINYGLTF3_MEMSET(model, 0, sizeof(*model));
     model->default_scene = -1;
 }
 
@@ -462,7 +587,7 @@ static int tg3__json_number_to_int32(const tg3json_value *v, int32_t *out) {
         return 1;
     }
     real = v->u.real;
-    if (!isfinite(real) || real < (double)INT32_MIN || real > (double)INT32_MAX) {
+    if (!tg3__isfinite(real) || real < (double)INT32_MIN || real > (double)INT32_MAX) {
         return 0;
     }
     converted = (int32_t)real;
@@ -485,7 +610,7 @@ static int tg3__json_number_to_uint64(const tg3json_value *v, uint64_t *out) {
         return 1;
     }
     real = v->u.real;
-    if (!isfinite(real) || real < 0.0 || real > max_safe_uint64_real) {
+    if (!tg3__isfinite(real) || real < 0.0 || real > max_safe_uint64_real) {
         return 0;
     }
     converted = (uint64_t)real;
@@ -783,7 +908,7 @@ static int tg3__parse_string_array(tg3__parse_ctx *ctx, const tg3json_value *o,
 static tg3_value tg3__json_to_value(tg3__parse_ctx *ctx, const tg3json_value *j) {
     tg3_value v;
     size_t i;
-    memset(&v, 0, sizeof(v));
+    TINYGLTF3_MEMSET(&v, 0, sizeof(v));
     if (!j) return v;
     switch (j->type) {
         case TG3JSON_NULL:
@@ -839,7 +964,7 @@ static void tg3__parse_extras_and_extensions(tg3__parse_ctx *ctx, const tg3json_
                                              tg3_extras_ext *ee) {
     const tg3json_value *extras_it;
     const tg3json_value *ext_it;
-    memset(ee, 0, sizeof(*ee));
+    TINYGLTF3_MEMSET(ee, 0, sizeof(*ee));
     extras_it = tg3__json_get(o, "extras");
     if (extras_it) {
         if (!ctx->opts.skip_extras_values) {
@@ -854,7 +979,7 @@ static void tg3__parse_extras_and_extensions(tg3__parse_ctx *ctx, const tg3json_
             char *raw = tg3json_stringify(extras_it, &raw_len);
             if (raw) {
                 ee->extras_json = tg3__arena_str(ctx->arena, raw, (uint32_t)raw_len);
-                free(raw);
+                TINYGLTF3_FREE(raw);
             }
         }
     }
@@ -867,7 +992,7 @@ static void tg3__parse_extras_and_extensions(tg3__parse_ctx *ctx, const tg3json_
             if (exts) {
                 for (i = 0; i < count; ++i) {
                     const tg3json_object_entry *entry = tg3json_object_at(ext_it, i);
-                    memset(&exts[i], 0, sizeof(exts[i]));
+                    TINYGLTF3_MEMSET(&exts[i], 0, sizeof(exts[i]));
                     exts[i].name = tg3__arena_str(ctx->arena, entry->key, (uint32_t)entry->key_len);
                     if (!ctx->opts.skip_extras_values) {
                         exts[i].value = tg3__json_to_value(ctx, entry->value);
@@ -884,17 +1009,17 @@ static void tg3__parse_extras_and_extensions(tg3__parse_ctx *ctx, const tg3json_
             char *raw = tg3json_stringify(ext_it, &raw_len);
             if (raw) {
                 ee->extensions_json = tg3__arena_str(ctx->arena, raw, (uint32_t)raw_len);
-                free(raw);
+                TINYGLTF3_FREE(raw);
             }
         }
     }
 }
 
-static void tg3__init_texture_info(tg3_texture_info *ti) { memset(ti, 0, sizeof(*ti)); ti->index = -1; }
-static void tg3__init_normal_texture_info(tg3_normal_texture_info *ti) { memset(ti, 0, sizeof(*ti)); ti->index = -1; ti->scale = 1.0; }
-static void tg3__init_occlusion_texture_info(tg3_occlusion_texture_info *ti) { memset(ti, 0, sizeof(*ti)); ti->index = -1; ti->strength = 1.0; }
+static void tg3__init_texture_info(tg3_texture_info *ti) { TINYGLTF3_MEMSET(ti, 0, sizeof(*ti)); ti->index = -1; }
+static void tg3__init_normal_texture_info(tg3_normal_texture_info *ti) { TINYGLTF3_MEMSET(ti, 0, sizeof(*ti)); ti->index = -1; ti->scale = 1.0; }
+static void tg3__init_occlusion_texture_info(tg3_occlusion_texture_info *ti) { TINYGLTF3_MEMSET(ti, 0, sizeof(*ti)); ti->index = -1; ti->strength = 1.0; }
 static void tg3__init_pbr(tg3_pbr_metallic_roughness *pbr) {
-    memset(pbr, 0, sizeof(*pbr));
+    TINYGLTF3_MEMSET(pbr, 0, sizeof(*pbr));
     pbr->base_color_factor[0] = 1.0; pbr->base_color_factor[1] = 1.0;
     pbr->base_color_factor[2] = 1.0; pbr->base_color_factor[3] = 1.0;
     pbr->metallic_factor = 1.0; pbr->roughness_factor = 1.0;
@@ -902,14 +1027,14 @@ static void tg3__init_pbr(tg3_pbr_metallic_roughness *pbr) {
     tg3__init_texture_info(&pbr->metallic_roughness_texture);
 }
 static void tg3__init_node(tg3_node *n) {
-    memset(n, 0, sizeof(*n));
+    TINYGLTF3_MEMSET(n, 0, sizeof(*n));
     n->camera = -1; n->skin = -1; n->mesh = -1; n->light = -1; n->emitter = -1;
     n->rotation[3] = 1.0; n->scale[0] = 1.0; n->scale[1] = 1.0; n->scale[2] = 1.0;
     n->matrix[0] = 1.0; n->matrix[5] = 1.0; n->matrix[10] = 1.0; n->matrix[15] = 1.0;
 }
 
 static int tg3__parse_asset(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_asset *asset) {
-    memset(asset, 0, sizeof(*asset));
+    TINYGLTF3_MEMSET(asset, 0, sizeof(*asset));
     tg3__parse_string(ctx, o, "version", &asset->version, 0, "/asset");
     tg3__parse_string(ctx, o, "generator", &asset->generator, 0, "/asset");
     tg3__parse_string(ctx, o, "minVersion", &asset->min_version, 0, "/asset");
@@ -957,20 +1082,20 @@ static int tg3__parse_occlusion_texture_info(tg3__parse_ctx *ctx, const tg3json_
 }
 
 static int tg3__accessor_type_from_string(const char *s, size_t len) {
-    if (len == 6 && memcmp(s, "SCALAR", 6) == 0) return TG3_TYPE_SCALAR;
-    if (len == 4 && memcmp(s, "VEC2", 4) == 0) return TG3_TYPE_VEC2;
-    if (len == 4 && memcmp(s, "VEC3", 4) == 0) return TG3_TYPE_VEC3;
-    if (len == 4 && memcmp(s, "VEC4", 4) == 0) return TG3_TYPE_VEC4;
-    if (len == 4 && memcmp(s, "MAT2", 4) == 0) return TG3_TYPE_MAT2;
-    if (len == 4 && memcmp(s, "MAT3", 4) == 0) return TG3_TYPE_MAT3;
-    if (len == 4 && memcmp(s, "MAT4", 4) == 0) return TG3_TYPE_MAT4;
+    if (len == 6 && TINYGLTF3_MEMCMP(s, "SCALAR", 6) == 0) return TG3_TYPE_SCALAR;
+    if (len == 4 && TINYGLTF3_MEMCMP(s, "VEC2", 4) == 0) return TG3_TYPE_VEC2;
+    if (len == 4 && TINYGLTF3_MEMCMP(s, "VEC3", 4) == 0) return TG3_TYPE_VEC3;
+    if (len == 4 && TINYGLTF3_MEMCMP(s, "VEC4", 4) == 0) return TG3_TYPE_VEC4;
+    if (len == 4 && TINYGLTF3_MEMCMP(s, "MAT2", 4) == 0) return TG3_TYPE_MAT2;
+    if (len == 4 && TINYGLTF3_MEMCMP(s, "MAT3", 4) == 0) return TG3_TYPE_MAT3;
+    if (len == 4 && TINYGLTF3_MEMCMP(s, "MAT4", 4) == 0) return TG3_TYPE_MAT4;
     return -1;
 }
 
 static int tg3__parse_accessor_sparse(tg3__parse_ctx *ctx, const tg3json_value *o,
                                       tg3_accessor_sparse *sparse) {
     const tg3json_value *it = tg3__json_get(o, "sparse");
-    memset(sparse, 0, sizeof(*sparse));
+    TINYGLTF3_MEMSET(sparse, 0, sizeof(*sparse));
     sparse->indices.buffer_view = -1;
     sparse->values.buffer_view = -1;
     if (!it) return 1;
@@ -1006,7 +1131,7 @@ static int tg3__parse_accessor(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_
     tg3_str type_str;
     uint64_t bo = 0;
     uint64_t cnt = 0;
-    memset(acc, 0, sizeof(*acc));
+    TINYGLTF3_MEMSET(acc, 0, sizeof(*acc));
     acc->buffer_view = -1;
     acc->component_type = -1;
     acc->type = -1;
@@ -1035,7 +1160,7 @@ static int tg3__uri_is_safe(const char *uri, uint32_t uri_len) {
     uint32_t i;
     if (!uri || uri_len == 0) return 0;
     /* No NUL bytes — fopen would truncate; protects against smuggling. */
-    if (memchr(uri, '\0', uri_len) != NULL) return 0;
+    if (TINYGLTF3_MEMCHR(uri, '\0', uri_len) != NULL) return 0;
     /* Reject absolute paths (POSIX and Windows). */
     if (uri[0] == '/' || uri[0] == '\\') return 0;
     /* Reject Windows drive prefixes like "C:". */
@@ -1075,14 +1200,14 @@ static int tg3__load_external_file(tg3__parse_ctx *ctx, uint8_t **out_data, uint
     if (uri_len >= sizeof(path_buf)) return 0;
     if (ctx->base_dir_len > 0) {
         if (ctx->base_dir_len >= sizeof(path_buf) - uri_len - 1u) return 0;
-        memcpy(path_buf, ctx->base_dir, ctx->base_dir_len);
+        TINYGLTF3_MEMCPY(path_buf, ctx->base_dir, ctx->base_dir_len);
         path_len = ctx->base_dir_len;
         if (path_len > 0 && path_buf[path_len - 1u] != '/' && path_buf[path_len - 1u] != '\\') {
             path_buf[path_len++] = '/';
         }
     }
     if (path_len + uri_len >= sizeof(path_buf)) return 0;
-    memcpy(path_buf + path_len, uri, uri_len);
+    TINYGLTF3_MEMCPY(path_buf + path_len, uri, uri_len);
     path_len += uri_len;
     path_buf[path_len] = '\0';
     ok = ctx->opts.fs.read_file(out_data, out_size, path_buf, path_len, ctx->opts.fs.user_data);
@@ -1111,7 +1236,7 @@ static int tg3__load_external_file(tg3__parse_ctx *ctx, uint8_t **out_data, uint
 static int tg3__parse_buffer(tg3__parse_ctx *ctx, const tg3json_value *o,
                              tg3_buffer *buf, int32_t buf_idx) {
     uint64_t byte_length = 0;
-    memset(buf, 0, sizeof(*buf));
+    TINYGLTF3_MEMSET(buf, 0, sizeof(*buf));
     tg3__parse_string(ctx, o, "name", &buf->name, 0, "/buffer");
     tg3__parse_string(ctx, o, "uri", &buf->uri, 0, "/buffer");
     tg3__parse_uint64(ctx, o, "byteLength", &byte_length, 1, "/buffer");
@@ -1140,7 +1265,7 @@ static int tg3__parse_buffer(tg3__parse_ctx *ctx, const tg3json_value *o,
                             "OOM for buffer data", NULL, -1);
             return 0;
         }
-        if (byte_length > 0) memcpy(data, ctx->bin_data, (size_t)byte_length);
+        if (byte_length > 0) TINYGLTF3_MEMCPY(data, ctx->bin_data, (size_t)byte_length);
         buf->data.data = data;
         buf->data.count = byte_length;
     } else if (buf->uri.len > 0) {
@@ -1148,7 +1273,7 @@ static int tg3__parse_buffer(tg3__parse_ctx *ctx, const tg3json_value *o,
             size_t decoded_len = 0;
             char mime[64];
             uint8_t *decoded;
-            memset(mime, 0, sizeof(mime));
+            TINYGLTF3_MEMSET(mime, 0, sizeof(mime));
             decoded = tg3__decode_data_uri(ctx->arena, buf->uri.data, buf->uri.len, &decoded_len, mime, sizeof(mime));
             if (!decoded && byte_length > 0) {
                 tg3__error_push(ctx->errors, TG3_SEVERITY_ERROR, TG3_ERR_DATA_URI_DECODE,
@@ -1171,7 +1296,7 @@ static int tg3__parse_buffer(tg3__parse_ctx *ctx, const tg3json_value *o,
                 }
                 data = (uint8_t *)tg3__arena_alloc(ctx->arena, (size_t)file_size);
                 if (data) {
-                    memcpy(data, file_data, (size_t)file_size);
+                    TINYGLTF3_MEMCPY(data, file_data, (size_t)file_size);
                     buf->data.data = data;
                     buf->data.count = file_size;
                 } else if (file_size > 0) {
@@ -1189,7 +1314,7 @@ static int tg3__parse_buffer(tg3__parse_ctx *ctx, const tg3json_value *o,
 static int tg3__parse_buffer_view(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_buffer_view *bv) {
     uint64_t val = 0;
     int32_t stride = 0;
-    memset(bv, 0, sizeof(*bv));
+    TINYGLTF3_MEMSET(bv, 0, sizeof(*bv));
     bv->buffer = -1;
     tg3__parse_string(ctx, o, "name", &bv->name, 0, "/bufferView");
     tg3__parse_int(ctx, o, "buffer", &bv->buffer, 1, "/bufferView");
@@ -1218,7 +1343,7 @@ static int tg3__parse_buffer_view(tg3__parse_ctx *ctx, const tg3json_value *o, t
 
 static int tg3__parse_image(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_image *img, int32_t img_idx) {
     (void)img_idx;
-    memset(img, 0, sizeof(*img));
+    TINYGLTF3_MEMSET(img, 0, sizeof(*img));
     img->width = -1; img->height = -1; img->component = -1; img->bits = -1; img->pixel_type = -1; img->buffer_view = -1;
     tg3__parse_string(ctx, o, "name", &img->name, 0, "/image");
     tg3__parse_string(ctx, o, "uri", &img->uri, 0, "/image");
@@ -1230,7 +1355,7 @@ static int tg3__parse_image(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_ima
 }
 
 static int tg3__parse_sampler(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_sampler *samp) {
-    memset(samp, 0, sizeof(*samp));
+    TINYGLTF3_MEMSET(samp, 0, sizeof(*samp));
     samp->min_filter = -1; samp->mag_filter = -1;
     samp->wrap_s = TG3_TEXTURE_WRAP_REPEAT; samp->wrap_t = TG3_TEXTURE_WRAP_REPEAT;
     tg3__parse_string(ctx, o, "name", &samp->name, 0, "/sampler");
@@ -1243,7 +1368,7 @@ static int tg3__parse_sampler(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_s
 }
 
 static int tg3__parse_texture(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_texture *tex) {
-    memset(tex, 0, sizeof(*tex));
+    TINYGLTF3_MEMSET(tex, 0, sizeof(*tex));
     tex->sampler = -1; tex->source = -1;
     tg3__parse_string(ctx, o, "name", &tex->name, 0, "/texture");
     tg3__parse_int(ctx, o, "sampler", &tex->sampler, 0, "/texture");
@@ -1255,7 +1380,7 @@ static int tg3__parse_texture(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_t
 static int tg3__parse_material(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_material *mat) {
     const tg3json_value *pbr_it;
     const tg3json_value *ext_it;
-    memset(mat, 0, sizeof(*mat));
+    TINYGLTF3_MEMSET(mat, 0, sizeof(*mat));
     tg3__init_pbr(&mat->pbr_metallic_roughness);
     tg3__init_normal_texture_info(&mat->normal_texture);
     tg3__init_occlusion_texture_info(&mat->occlusion_texture);
@@ -1297,7 +1422,7 @@ static int tg3__parse_material(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_
 static int tg3__parse_primitive(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_primitive *prim) {
     const tg3json_value *attr_it;
     const tg3json_value *targets_it;
-    memset(prim, 0, sizeof(*prim));
+    TINYGLTF3_MEMSET(prim, 0, sizeof(*prim));
     prim->material = -1; prim->indices = -1; prim->mode = TG3_MODE_TRIANGLES;
     tg3__parse_int(ctx, o, "material", &prim->material, 0, "/primitive");
     tg3__parse_int(ctx, o, "indices", &prim->indices, 0, "/primitive");
@@ -1375,7 +1500,7 @@ static int tg3__parse_primitive(tg3__parse_ctx *ctx, const tg3json_value *o, tg3
 
 static int tg3__parse_mesh(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_mesh *mesh) {
     const tg3json_value *prim_it = tg3__json_get(o, "primitives");
-    memset(mesh, 0, sizeof(*mesh));
+    TINYGLTF3_MEMSET(mesh, 0, sizeof(*mesh));
     tg3__parse_string(ctx, o, "name", &mesh->name, 0, "/mesh");
     if (tg3__json_is_array(prim_it)) {
         size_t count = tg3json_array_size(prim_it);
@@ -1421,7 +1546,7 @@ static int tg3__parse_node(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_node
 }
 
 static int tg3__parse_skin(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_skin *skin) {
-    memset(skin, 0, sizeof(*skin));
+    TINYGLTF3_MEMSET(skin, 0, sizeof(*skin));
     skin->inverse_bind_matrices = -1; skin->skeleton = -1;
     tg3__parse_string(ctx, o, "name", &skin->name, 0, "/skin");
     tg3__parse_int(ctx, o, "inverseBindMatrices", &skin->inverse_bind_matrices, 0, "/skin");
@@ -1434,7 +1559,7 @@ static int tg3__parse_skin(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_skin
 static int tg3__parse_animation(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_animation *anim) {
     const tg3json_value *ch_it = tg3__json_get(o, "channels");
     const tg3json_value *samp_it = tg3__json_get(o, "samplers");
-    memset(anim, 0, sizeof(*anim));
+    TINYGLTF3_MEMSET(anim, 0, sizeof(*anim));
     tg3__parse_string(ctx, o, "name", &anim->name, 0, "/animation");
     if (tg3__json_is_array(ch_it)) {
         size_t count = tg3json_array_size(ch_it);
@@ -1445,7 +1570,7 @@ static int tg3__parse_animation(tg3__parse_ctx *ctx, const tg3json_value *o, tg3
                 for (i = 0; i < count; ++i) {
                     const tg3json_value *item = tg3json_array_get(ch_it, i);
                     const tg3json_value *tgt_it;
-                    memset(&channels[i], 0, sizeof(channels[i]));
+                    TINYGLTF3_MEMSET(&channels[i], 0, sizeof(channels[i]));
                     channels[i].sampler = -1;
                     channels[i].target.node = -1;
                     tg3__parse_int(ctx, item, "sampler", &channels[i].sampler, 1, "/animation/channel");
@@ -1471,7 +1596,7 @@ static int tg3__parse_animation(tg3__parse_ctx *ctx, const tg3json_value *o, tg3
                 for (i = 0; i < count; ++i) {
                     const tg3json_value *item = tg3json_array_get(samp_it, i);
                     tg3_str interp;
-                    memset(&samplers[i], 0, sizeof(samplers[i]));
+                    TINYGLTF3_MEMSET(&samplers[i], 0, sizeof(samplers[i]));
                     samplers[i].input = -1; samplers[i].output = -1;
                     tg3__parse_int(ctx, item, "input", &samplers[i].input, 1, "/animation/sampler");
                     tg3__parse_int(ctx, item, "output", &samplers[i].output, 1, "/animation/sampler");
@@ -1491,7 +1616,7 @@ static int tg3__parse_animation(tg3__parse_ctx *ctx, const tg3json_value *o, tg3
 
 static int tg3__parse_camera(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_camera *cam) {
     const tg3json_value *it;
-    memset(cam, 0, sizeof(*cam));
+    TINYGLTF3_MEMSET(cam, 0, sizeof(*cam));
     tg3__parse_string(ctx, o, "name", &cam->name, 0, "/camera");
     tg3__parse_string(ctx, o, "type", &cam->type, 1, "/camera");
     if (cam->type.data && tg3_str_equals_cstr(cam->type, "perspective")) {
@@ -1519,7 +1644,7 @@ static int tg3__parse_camera(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_ca
 
 static int tg3__parse_scene(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_scene *scene) {
     const tg3json_value *ext_it;
-    memset(scene, 0, sizeof(*scene));
+    TINYGLTF3_MEMSET(scene, 0, sizeof(*scene));
     tg3__parse_string(ctx, o, "name", &scene->name, 0, "/scene");
     tg3__parse_int_array(ctx, o, "nodes", &scene->nodes, &scene->nodes_count, 0, "/scene");
     ext_it = tg3__json_get(o, "extensions");
@@ -1535,7 +1660,7 @@ static int tg3__parse_scene(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_sce
 
 static int tg3__parse_light(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_light *light) {
     const tg3json_value *spot_it;
-    memset(light, 0, sizeof(*light));
+    TINYGLTF3_MEMSET(light, 0, sizeof(*light));
     light->color[0] = 1.0; light->color[1] = 1.0; light->color[2] = 1.0;
     light->intensity = 1.0; light->spot.outer_cone_angle = 0.7853981634;
     tg3__parse_string(ctx, o, "name", &light->name, 0, "/light");
@@ -1554,7 +1679,7 @@ static int tg3__parse_light(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_lig
 }
 
 static int tg3__parse_audio_source(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_audio_source *src) {
-    memset(src, 0, sizeof(*src));
+    TINYGLTF3_MEMSET(src, 0, sizeof(*src));
     src->buffer_view = -1;
     tg3__parse_string(ctx, o, "name", &src->name, 0, "/audioSource");
     tg3__parse_string(ctx, o, "uri", &src->uri, 0, "/audioSource");
@@ -1566,7 +1691,7 @@ static int tg3__parse_audio_source(tg3__parse_ctx *ctx, const tg3json_value *o,
 
 static int tg3__parse_audio_emitter(tg3__parse_ctx *ctx, const tg3json_value *o, tg3_audio_emitter *emitter) {
     const tg3json_value *pos_it;
-    memset(emitter, 0, sizeof(*emitter));
+    TINYGLTF3_MEMSET(emitter, 0, sizeof(*emitter));
     emitter->gain = 1.0; emitter->source = -1;
     emitter->positional.cone_inner_angle = 6.283185307179586;
     emitter->positional.cone_outer_angle = 6.283185307179586;
@@ -2093,7 +2218,7 @@ static tg3_error_code tg3__parse_from_json(tg3__parse_ctx *ctx, const tg3json_va
 
 static void tg3__json_parse_options_from_tg3(const tg3_parse_options *options,
                                              tg3json_parse_options *json_options) {
-    memset(json_options, 0, sizeof(*json_options));
+    TINYGLTF3_MEMSET(json_options, 0, sizeof(*json_options));
     json_options->depth_limit = TINYGLTF3_MAX_NESTING_DEPTH;
     json_options->memory_budget = options ? (size_t)options->memory.memory_budget : 0;
     json_options->max_single_alloc = options ? (size_t)options->memory.max_single_alloc : 0;
@@ -2119,13 +2244,13 @@ static tg3_error_code tg3__parse_glb_header(const uint8_t *data, uint64_t size,
                         "Invalid GLB magic bytes", NULL, -1);
         return TG3_ERR_GLB_INVALID_MAGIC;
     }
-    memcpy(&version, data + 4, 4);
+    TINYGLTF3_MEMCPY(&version, data + 4, 4);
     if (version != 2) {
         tg3__error_push(errors, TG3_SEVERITY_ERROR, TG3_ERR_GLB_INVALID_VERSION,
                         "Unsupported GLB version (expected 2)", NULL, -1);
         return TG3_ERR_GLB_INVALID_VERSION;
     }
-    memcpy(&total_length, data + 8, 4);
+    TINYGLTF3_MEMCPY(&total_length, data + 8, 4);
     if ((uint64_t)total_length != size) {
         tg3__error_push(errors, TG3_SEVERITY_ERROR, TG3_ERR_GLB_SIZE_MISMATCH,
                         "GLB total length does not match data size", NULL, -1);
@@ -2134,8 +2259,8 @@ static tg3_error_code tg3__parse_glb_header(const uint8_t *data, uint64_t size,
     while (offset + 8 <= (uint64_t)total_length) {
         uint32_t chunk_length;
         uint32_t chunk_type;
-        memcpy(&chunk_length, data + offset, 4); offset += 4;
-        memcpy(&chunk_type, data + offset, 4); offset += 4;
+        TINYGLTF3_MEMCPY(&chunk_length, data + offset, 4); offset += 4;
+        TINYGLTF3_MEMCPY(&chunk_type, data + offset, 4); offset += 4;
         if (offset + chunk_length > (uint64_t)total_length) {
             tg3__error_push(errors, TG3_SEVERITY_ERROR, TG3_ERR_GLB_CHUNK_ERROR,
                             "GLB chunk exceeds data size", NULL, -1);
@@ -2192,13 +2317,13 @@ TINYGLTF3_API tg3_error_code tg3_parse(tg3_model *model, tg3_error_stack *errors
          * the caller; tg3_model_free is the sole arena owner on the error path. */
         return TG3_ERR_JSON_PARSE;
     }
-    memset(&ctx, 0, sizeof(ctx));
+    TINYGLTF3_MEMSET(&ctx, 0, sizeof(ctx));
     ctx.arena = arena;
     ctx.errors = errors;
     ctx.opts = *options;
     ctx.base_dir = base_dir;
     ctx.base_dir_len = base_dir_len;
-#ifdef TINYGLTF3_ENABLE_FS
+#if defined(TINYGLTF3_ENABLE_FS) && !defined(TINYGLTF3_NO_STDLIB)
     tg3__set_default_fs(&ctx.opts.fs);
 #endif
     ret = tg3__parse_from_json(&ctx, &json_doc, model);
@@ -2250,7 +2375,7 @@ TINYGLTF3_API tg3_error_code tg3_parse_glb(tg3_model *model, tg3_error_stack *er
         /* Keep arena alive so error messages stay valid; model_free owns it. */
         return TG3_ERR_JSON_PARSE;
     }
-    memset(&ctx, 0, sizeof(ctx));
+    TINYGLTF3_MEMSET(&ctx, 0, sizeof(ctx));
     ctx.arena = arena;
     ctx.errors = errors;
     ctx.opts = *options;
@@ -2259,7 +2384,7 @@ TINYGLTF3_API tg3_error_code tg3_parse_glb(tg3_model *model, tg3_error_stack *er
     ctx.is_binary = 1;
     ctx.bin_data = bin_chunk;
     ctx.bin_size = bin_chunk_size;
-#ifdef TINYGLTF3_ENABLE_FS
+#if defined(TINYGLTF3_ENABLE_FS) && !defined(TINYGLTF3_NO_STDLIB)
     tg3__set_default_fs(&ctx.opts.fs);
 #endif
     err = tg3__parse_from_json(&ctx, &json_doc, model);
@@ -2298,7 +2423,7 @@ TINYGLTF3_API tg3_error_code tg3_parse_file(tg3_model *model, tg3_error_stack *e
     if (!filename) return TG3_ERR_FILE_NOT_FOUND;
     if (options) opts = *options;
     else tg3_parse_options_init(&opts);
-#ifdef TINYGLTF3_ENABLE_FS
+#if defined(TINYGLTF3_ENABLE_FS) && !defined(TINYGLTF3_NO_STDLIB)
     tg3__set_default_fs(&opts.fs);
 #endif
     if (!opts.fs.read_file) {
@@ -2311,12 +2436,12 @@ TINYGLTF3_API tg3_error_code tg3_parse_file(tg3_model *model, tg3_error_stack *e
                         "Failed to read file", NULL, -1);
         return TG3_ERR_FILE_NOT_FOUND;
     }
-    memset(base_dir_buf, 0, sizeof(base_dir_buf));
+    TINYGLTF3_MEMSET(base_dir_buf, 0, sizeof(base_dir_buf));
     for (i = 0; i < filename_len; ++i) {
         if (filename[i] == '/' || filename[i] == '\\') base_dir_len = i;
     }
     if (base_dir_len > 0) {
-        memcpy(base_dir_buf, filename, base_dir_len);
+        TINYGLTF3_MEMCPY(base_dir_buf, filename, base_dir_len);
         base_dir_buf[base_dir_len] = '\0';
     }
     result = tg3_parse_auto(model, errors, file_data, file_size, base_dir_buf, base_dir_len, &opts);
@@ -2327,7 +2452,7 @@ TINYGLTF3_API tg3_error_code tg3_parse_file(tg3_model *model, tg3_error_stack *e
 TINYGLTF3_API void tg3_model_free(tg3_model *model) {
     if (!model) return;
     if (model->arena_) tg3__arena_destroy(model->arena_);
-    memset(model, 0, sizeof(*model));
+    TINYGLTF3_MEMSET(model, 0, sizeof(*model));
     model->default_scene = -1;
 }
 
@@ -2335,7 +2460,7 @@ static char *tg3__b64_encode(const uint8_t *input, size_t input_len, size_t *out
     static const char chars[] =
         "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
     size_t enc_len = ((input_len + 2u) / 3u) * 4u;
-    char *out = (char *)malloc(enc_len + 1u);
+    char *out = (char *)TINYGLTF3_MALLOC(enc_len + 1u);
     size_t i;
     size_t j = 0;
     if (!out) return NULL;
@@ -2408,7 +2533,7 @@ static int tg3__json_set_string_n(tg3json_value *obj, const char *key, const cha
 }
 
 static int tg3__json_set_string(tg3json_value *obj, const char *key, const char *str) {
-    return tg3__json_set_string_n(obj, key, str, str ? strlen(str) : 0);
+    return tg3__json_set_string_n(obj, key, str, str ? TINYGLTF3_STRLEN(str) : 0);
 }
 
 static int tg3__json_array_append_int(tg3json_value *arr, int64_t value) {
@@ -2478,7 +2603,7 @@ static int tg3__serialize_uint64(tg3json_value *o, const char *key, uint64_t val
 
 static int tg3__serialize_double(tg3json_value *o, const char *key, double val,
                                  double default_val, int write_defaults) {
-    if (fabs(val - default_val) <= 1e-12 && !write_defaults) return 1;
+    if (tg3__fabs(val - default_val) <= 1e-12 && !write_defaults) return 1;
     return tg3__json_set_real(o, key, val);
 }
 
@@ -2724,22 +2849,22 @@ static int tg3__serialize_buffer(const tg3_buffer *b, int wd, int embed, tg3json
             tg3json_value_free(out);
             return 0;
         }
-        uri = (char *)malloc(prefix_len + enc_len + 1u);
+        uri = (char *)TINYGLTF3_MALLOC(prefix_len + enc_len + 1u);
         if (!uri) {
-            free(encoded);
+            TINYGLTF3_FREE(encoded);
             tg3json_value_free(out);
             return 0;
         }
-        memcpy(uri, prefix, prefix_len);
-        memcpy(uri + prefix_len, encoded, enc_len);
+        TINYGLTF3_MEMCPY(uri, prefix, prefix_len);
+        TINYGLTF3_MEMCPY(uri + prefix_len, encoded, enc_len);
         uri[prefix_len + enc_len] = '\0';
-        free(encoded);
+        TINYGLTF3_FREE(encoded);
         if (!tg3__json_set_string_n(out, "uri", uri, prefix_len + enc_len)) {
-            free(uri);
+            TINYGLTF3_FREE(uri);
             tg3json_value_free(out);
             return 0;
         }
-        free(uri);
+        TINYGLTF3_FREE(uri);
     }
     if (!tg3__serialize_extras_ext(out, &b->ext)) {
         tg3json_value_free(out);
@@ -2887,9 +3012,9 @@ static int tg3__serialize_material(const tg3_material *m, int wd, tg3json_value
         has_pbr = 1;
     }
     if (!tg3__serialize_double(&pbr, "metallicFactor", p->metallic_factor, 1.0, wd)) goto fail;
-    if (fabs(p->metallic_factor - 1.0) > 1e-12 || wd) has_pbr = 1;
+    if (tg3__fabs(p->metallic_factor - 1.0) > 1e-12 || wd) has_pbr = 1;
     if (!tg3__serialize_double(&pbr, "roughnessFactor", p->roughness_factor, 1.0, wd)) goto fail;
-    if (fabs(p->roughness_factor - 1.0) > 1e-12 || wd) has_pbr = 1;
+    if (tg3__fabs(p->roughness_factor - 1.0) > 1e-12 || wd) has_pbr = 1;
     if (p->base_color_texture.index >= 0) {
         if (!tg3__serialize_texture_info(&pbr, "baseColorTexture", &p->base_color_texture, wd)) goto fail;
         has_pbr = 1;
@@ -3343,22 +3468,22 @@ TINYGLTF3_API tg3_error_code tg3_write_to_memory(const tg3_model *model, tg3_err
         }
         bin_padded = ((uint32_t)bin_len + 3u) & ~3u;
         total = 12u + 8u + json_padded + ((bin_data && bin_len > 0) ? (8u + bin_padded) : 0u);
-        glb = (uint8_t *)malloc(total);
+        glb = (uint8_t *)TINYGLTF3_MALLOC(total);
         if (!glb) {
-            free(json_str);
+            TINYGLTF3_FREE(json_str);
             tg3__error_push(errors, TG3_SEVERITY_ERROR, TG3_ERR_OUT_OF_MEMORY,
                             "OOM allocating GLB output", NULL, -1);
             return TG3_ERR_OUT_OF_MEMORY;
         }
-        memcpy(glb, "glTF", 4);
+        TINYGLTF3_MEMCPY(glb, "glTF", 4);
         {
             uint32_t version = 2u;
             uint32_t json_type = 0x4E4F534Au;
-            memcpy(glb + 4, &version, 4);
-            memcpy(glb + 8, &total, 4);
-            memcpy(glb + 12, &json_padded, 4);
-            memcpy(glb + 16, &json_type, 4);
-            memcpy(glb + 20, json_str, json_len);
+            TINYGLTF3_MEMCPY(glb + 4, &version, 4);
+            TINYGLTF3_MEMCPY(glb + 8, &total, 4);
+            TINYGLTF3_MEMCPY(glb + 12, &json_padded, 4);
+            TINYGLTF3_MEMCPY(glb + 16, &json_type, 4);
+            TINYGLTF3_MEMCPY(glb + 20, json_str, json_len);
         }
         while ((uint32_t)json_len < json_padded) {
             glb[20u + json_len] = ' ';
@@ -3368,25 +3493,25 @@ TINYGLTF3_API tg3_error_code tg3_write_to_memory(const tg3_model *model, tg3_err
             uint32_t bin_off = 20u + json_padded;
             uint32_t bin_type = 0x004E4942u;
             uint32_t i;
-            memcpy(glb + bin_off, &bin_padded, 4);
-            memcpy(glb + bin_off + 4u, &bin_type, 4);
-            memcpy(glb + bin_off + 8u, bin_data, (size_t)bin_len);
+            TINYGLTF3_MEMCPY(glb + bin_off, &bin_padded, 4);
+            TINYGLTF3_MEMCPY(glb + bin_off + 4u, &bin_type, 4);
+            TINYGLTF3_MEMCPY(glb + bin_off + 8u, bin_data, (size_t)bin_len);
             for (i = (uint32_t)bin_len; i < bin_padded; ++i) glb[bin_off + 8u + i] = 0;
         }
-        free(json_str);
+        TINYGLTF3_FREE(json_str);
         *out_data = glb;
         *out_size = total;
         return TG3_OK;
     } else {
-        uint8_t *data = (uint8_t *)malloc(json_len);
+        uint8_t *data = (uint8_t *)TINYGLTF3_MALLOC(json_len);
         if (!data) {
-            free(json_str);
+            TINYGLTF3_FREE(json_str);
             tg3__error_push(errors, TG3_SEVERITY_ERROR, TG3_ERR_OUT_OF_MEMORY,
                             "OOM allocating JSON output", NULL, -1);
             return TG3_ERR_OUT_OF_MEMORY;
         }
-        memcpy(data, json_str, json_len);
-        free(json_str);
+        TINYGLTF3_MEMCPY(data, json_str, json_len);
+        TINYGLTF3_FREE(json_str);
         *out_data = data;
         *out_size = (uint64_t)json_len;
         return TG3_OK;
@@ -3403,7 +3528,7 @@ TINYGLTF3_API tg3_error_code tg3_write_to_file(const tg3_model *model, tg3_error
     int32_t ok;
     if (options) opts = *options;
     else tg3_write_options_init(&opts);
-#ifdef TINYGLTF3_ENABLE_FS
+#if defined(TINYGLTF3_ENABLE_FS) && !defined(TINYGLTF3_NO_STDLIB)
     tg3__set_default_fs(&opts.fs);
 #endif
     if (!opts.fs.write_file) {
@@ -3414,7 +3539,7 @@ TINYGLTF3_API tg3_error_code tg3_write_to_file(const tg3_model *model, tg3_error
     err = tg3_write_to_memory(model, errors, &data, &size, &opts);
     if (err != TG3_OK) return err;
     ok = opts.fs.write_file(filename, filename_len, data, size, opts.fs.user_data);
-    free(data);
+    TINYGLTF3_FREE(data);
     if (!ok) {
         tg3__error_push(errors, TG3_SEVERITY_ERROR, TG3_ERR_FILE_WRITE,
                         "Failed to write file", NULL, -1);
@@ -3425,14 +3550,14 @@ TINYGLTF3_API tg3_error_code tg3_write_to_file(const tg3_model *model, tg3_error
 
 TINYGLTF3_API void tg3_write_free(uint8_t *data, const tg3_write_options *options) {
     (void)options;
-    free(data);
+    TINYGLTF3_FREE(data);
 }
 
 TINYGLTF3_API tg3_writer *tg3_writer_create(tg3_write_chunk_fn chunk_fn, void *user_data,
                                             const tg3_write_options *options) {
-    tg3_writer *w = (tg3_writer *)malloc(sizeof(tg3_writer));
+    tg3_writer *w = (tg3_writer *)TINYGLTF3_MALLOC(sizeof(tg3_writer));
     if (!w) return NULL;
-    memset(w, 0, sizeof(*w));
+    TINYGLTF3_MEMSET(w, 0, sizeof(*w));
     w->chunk_fn = chunk_fn;
     w->user_data = user_data;
     if (options) w->options = *options;
@@ -3508,12 +3633,12 @@ TINYGLTF3_API tg3_error_code tg3_writer_end(tg3_writer *w) {
         : tg3json_stringify(&w->root, &json_len);
     if (!json_str) return TG3_ERR_OUT_OF_MEMORY;
     ok = w->chunk_fn((const uint8_t *)json_str, (uint64_t)json_len, w->user_data);
-    free(json_str);
+    TINYGLTF3_FREE(json_str);
     return ok ? TG3_OK : TG3_ERR_WRITE_FAILED;
 }
 
 TINYGLTF3_API void tg3_writer_destroy(tg3_writer *w) {
     if (!w) return;
     tg3json_value_free(&w->root);
-    free(w);
+    TINYGLTF3_FREE(w);
 }
diff --git a/tiny_gltf_v3.h b/tiny_gltf_v3.h
index 3e4afe0..6cc1583 100644
--- a/tiny_gltf_v3.h
+++ b/tiny_gltf_v3.h
@@ -116,8 +116,12 @@
 
 /* Assert override */
 #ifndef TINYGLTF3_ASSERT
+#ifndef TINYGLTF3_NO_STDLIB
 #include <assert.h>
 #define TINYGLTF3_ASSERT(x) assert(x)
+#else
+#define TINYGLTF3_ASSERT(x) ((void)(x))
+#endif
 #endif
 
 /* ======================================================================
@@ -127,8 +131,34 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <stdarg.h>
+#ifndef TINYGLTF3_NO_STDLIB
 #include <string.h>
 #include <stdlib.h>
+#endif
+
+#ifndef TINYGLTF3_MALLOC
+#ifndef TINYGLTF3_NO_STDLIB
+#define TINYGLTF3_MALLOC(sz) malloc(sz)
+#else
+#define TINYGLTF3_MALLOC(sz) NULL
+#endif
+#endif
+
+#ifndef TINYGLTF3_REALLOC
+#ifndef TINYGLTF3_NO_STDLIB
+#define TINYGLTF3_REALLOC(ptr, sz) realloc((ptr), (sz))
+#else
+#define TINYGLTF3_REALLOC(ptr, sz) NULL
+#endif
+#endif
+
+#ifndef TINYGLTF3_FREE
+#ifndef TINYGLTF3_NO_STDLIB
+#define TINYGLTF3_FREE(ptr) free(ptr)
+#else
+#define TINYGLTF3_FREE(ptr) ((void)(ptr))
+#endif
+#endif
 
 /* ======================================================================
  * Section 4: Constants and Enums
diff --git a/tinygltf_json_c.h b/tinygltf_json_c.h
index 380a01d..abe3a2b 100644
--- a/tinygltf_json_c.h
+++ b/tinygltf_json_c.h
@@ -1,9 +1,24 @@
 #ifndef TINYGLTF_JSON_C_H_
 #define TINYGLTF_JSON_C_H_
 
+/*
+ * Floating-point conversion attribution:
+ *
+ * - JSON number parsing in this C11 port is based on fast_float.
+ *   Upstream: https://github.com/fastfloat/fast_float
+ *   Copyright (c) 2021 The fast_float authors.
+ *   License: Apache License 2.0, MIT License, or Boost Software License 1.0.
+ *
+ * - JSON number serialization in this C11 port is based on Dragonbox-style
+ *   shortest round-trippable binary floating-point to decimal conversion.
+ *   Upstream: https://github.com/jk-jeon/dragonbox
+ *   Copyright 2020-2024 Junekey Jeon.
+ *   License: Apache License 2.0 with LLVM Exceptions, or Boost Software
+ *   License 1.0.
+ */
+
 #include <stddef.h>
 #include <stdint.h>
-#include <stdio.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -111,9 +126,433 @@ char *tg3json_stringify_pretty(const tg3json_value *value, int indent, size_t *o
 
 #ifdef TINYGLTF_JSON_C_IMPLEMENTATION
 
-#include <errno.h>
-#include <stdlib.h>
-#include <string.h>
+#ifndef TINYGLTF_JSON_NO_STDLIB
+  #include <stdlib.h>
+  #include <string.h>
+#endif
+
+#ifdef TINYGLTF_JSON_NO_STDLIB
+static void *tg3json__memcpy_fallback(void *dst, const void *src, size_t sz) {
+    unsigned char *d = (unsigned char *)dst;
+    const unsigned char *s = (const unsigned char *)src;
+    while (sz--) *d++ = *s++;
+    return dst;
+}
+
+static void *tg3json__memset_fallback(void *dst, int val, size_t sz) {
+    unsigned char *d = (unsigned char *)dst;
+    while (sz--) *d++ = (unsigned char)val;
+    return dst;
+}
+
+static int tg3json__memcmp_fallback(const void *a, const void *b, size_t sz) {
+    const unsigned char *pa = (const unsigned char *)a;
+    const unsigned char *pb = (const unsigned char *)b;
+    while (sz--) {
+        if (*pa != *pb) return (int)*pa - (int)*pb;
+        ++pa;
+        ++pb;
+    }
+    return 0;
+}
+
+static size_t tg3json__strlen_fallback(const char *str) {
+    const char *p = str;
+    while (*p) ++p;
+    return (size_t)(p - str);
+}
+
+#endif
+
+#ifndef TINYGLTF_JSON_MALLOC
+#ifdef TINYGLTF_JSON_NO_STDLIB
+#define TINYGLTF_JSON_MALLOC(sz) NULL
+#else
+#define TINYGLTF_JSON_MALLOC(sz) malloc(sz)
+#endif
+#endif
+#ifndef TINYGLTF_JSON_REALLOC
+#ifdef TINYGLTF_JSON_NO_STDLIB
+#define TINYGLTF_JSON_REALLOC(ptr, sz) NULL
+#else
+#define TINYGLTF_JSON_REALLOC(ptr, sz) realloc(ptr, sz)
+#endif
+#endif
+#ifndef TINYGLTF_JSON_FREE
+#ifdef TINYGLTF_JSON_NO_STDLIB
+#define TINYGLTF_JSON_FREE(ptr) ((void)(ptr))
+#else
+#define TINYGLTF_JSON_FREE(ptr) free(ptr)
+#endif
+#endif
+
+#ifndef TINYGLTF_JSON_MEMCPY
+#ifdef TINYGLTF_JSON_NO_STDLIB
+#define TINYGLTF_JSON_MEMCPY(dst, src, sz) tg3json__memcpy_fallback((dst), (src), (sz))
+#else
+#define TINYGLTF_JSON_MEMCPY(dst, src, sz) memcpy(dst, src, sz)
+#endif
+#endif
+#ifndef TINYGLTF_JSON_MEMSET
+#ifdef TINYGLTF_JSON_NO_STDLIB
+#define TINYGLTF_JSON_MEMSET(dst, val, sz) tg3json__memset_fallback((dst), (val), (sz))
+#else
+#define TINYGLTF_JSON_MEMSET(dst, val, sz) memset(dst, val, sz)
+#endif
+#endif
+#ifndef TINYGLTF_JSON_MEMCMP
+#ifdef TINYGLTF_JSON_NO_STDLIB
+#define TINYGLTF_JSON_MEMCMP(a, b, sz) tg3json__memcmp_fallback((a), (b), (sz))
+#else
+#define TINYGLTF_JSON_MEMCMP(a, b, sz) memcmp(a, b, sz)
+#endif
+#endif
+#ifndef TINYGLTF_JSON_STRLEN
+#ifdef TINYGLTF_JSON_NO_STDLIB
+#define TINYGLTF_JSON_STRLEN(str) tg3json__strlen_fallback((str))
+#else
+#define TINYGLTF_JSON_STRLEN(str) strlen(str)
+#endif
+#endif
+
+static size_t tg3json__itoa(int64_t value, char *buf) {
+    char *p = buf;
+    uint64_t val;
+    char tmp[24];
+    int i = 0;
+    if (value < 0) {
+        *p++ = '-';
+        val = (value == -9223372036854775807LL - 1) ? 9223372036854775808ULL : (uint64_t)(-value);
+    } else {
+        val = (uint64_t)value;
+    }
+    if (val == 0) {
+        *p++ = '0';
+        *p = '\0';
+        return (size_t)(p - buf);
+    }
+    while (val > 0) {
+        tmp[i++] = (char)('0' + (val % 10));
+        val /= 10;
+    }
+    while (i > 0) {
+        *p++ = tmp[--i];
+    }
+    *p = '\0';
+    return (size_t)(p - buf);
+}
+
+static size_t tg3json__utoa(uint64_t value, char *buf) {
+    char tmp[32];
+    size_t n = 0;
+    size_t i = 0;
+    if (value == 0) {
+        buf[0] = '0';
+        buf[1] = '\0';
+        return 1;
+    }
+    while (value > 0) {
+        tmp[n++] = (char)('0' + (value % 10u));
+        value /= 10u;
+    }
+    while (n > 0) buf[i++] = tmp[--n];
+    buf[i] = '\0';
+    return i;
+}
+
+static uint64_t tg3json__double_bits(double v) {
+    uint64_t bits = 0;
+    TINYGLTF_JSON_MEMCPY(&bits, &v, sizeof(bits));
+    return bits;
+}
+
+static double tg3json__double_from_bits(uint64_t bits) {
+    double v = 0.0;
+    TINYGLTF_JSON_MEMCPY(&v, &bits, sizeof(v));
+    return v;
+}
+
+static int tg3json__is_nan_bits(uint64_t bits) {
+    return ((bits & 0x7ff0000000000000ULL) == 0x7ff0000000000000ULL) &&
+           ((bits & 0x000fffffffffffffULL) != 0);
+}
+
+static int tg3json__is_inf_bits(uint64_t bits) {
+    return (bits & 0x7fffffffffffffffULL) == 0x7ff0000000000000ULL;
+}
+
+static long double tg3json__pow10_ld(int exp10) {
+    long double v = 1.0L;
+    if (exp10 < 0) {
+        exp10 = -exp10;
+        while (exp10 >= 16) {
+            v *= 1.0e-16L;
+            exp10 -= 16;
+        }
+        while (exp10-- > 0) v *= 0.1L;
+    } else {
+        while (exp10 >= 16) {
+            v *= 1.0e16L;
+            exp10 -= 16;
+        }
+        while (exp10-- > 0) v *= 10.0L;
+    }
+    return v;
+}
+
+static int tg3json__parse_f64_c(const char *start, const char *end, double *out) {
+    const char *p = start;
+    int neg = 0;
+    int saw_digit = 0;
+    int nonzero_seen = 0;
+    int exp10 = 0;
+    uint64_t sig = 0;
+    int sig_digits = 0;
+    long double extra = 0.0L;
+    int extra_digits = 0;
+    int exp_sign = 1;
+    int exp_lit = 0;
+    long double v;
+
+    if (p < end && *p == '-') {
+        neg = 1;
+        ++p;
+    }
+    if (p >= end) return 0;
+    if (*p == '0') {
+        saw_digit = 1;
+        ++p;
+    } else if (*p >= '1' && *p <= '9') {
+        do {
+            int d = *p - '0';
+            saw_digit = 1;
+            nonzero_seen = 1;
+            if (sig_digits < 19) {
+                sig = sig * 10u + (uint64_t)d;
+                ++sig_digits;
+            } else if (extra_digits < 64) {
+                extra = extra * 10.0L + (long double)d;
+                ++extra_digits;
+            } else {
+                ++exp10;
+            }
+            ++p;
+        } while (p < end && *p >= '0' && *p <= '9');
+    } else {
+        return 0;
+    }
+    if (p < end && *p == '.') {
+        ++p;
+        if (p >= end || *p < '0' || *p > '9') return 0;
+        do {
+            int d = *p - '0';
+            saw_digit = 1;
+            if (d != 0 || nonzero_seen) {
+                nonzero_seen = nonzero_seen || (d != 0);
+                if (sig_digits < 19) {
+                    sig = sig * 10u + (uint64_t)d;
+                    ++sig_digits;
+                    --exp10;
+                } else if (extra_digits < 64) {
+                    extra = extra * 10.0L + (long double)d;
+                    ++extra_digits;
+                    --exp10;
+                } else {
+                    --exp10;
+                }
+            } else {
+                --exp10;
+            }
+            ++p;
+        } while (p < end && *p >= '0' && *p <= '9');
+    }
+    if (!saw_digit) return 0;
+    if (p < end && (*p == 'e' || *p == 'E')) {
+        ++p;
+        if (p < end && (*p == '+' || *p == '-')) {
+            exp_sign = (*p == '-') ? -1 : 1;
+            ++p;
+        }
+        if (p >= end || *p < '0' || *p > '9') return 0;
+        while (p < end && *p >= '0' && *p <= '9') {
+            if (exp_lit < 10000) exp_lit = exp_lit * 10 + (*p - '0');
+            ++p;
+        }
+        exp10 += exp_sign * exp_lit;
+    }
+    if (p != end) return 0;
+    if (!nonzero_seen || sig_digits == 0) {
+        *out = neg ? tg3json__double_from_bits(0x8000000000000000ULL) : 0.0;
+        return 1;
+    }
+    if (exp10 > 309) return 0;
+    if (exp10 < -4000) {
+        *out = neg ? tg3json__double_from_bits(0x8000000000000000ULL) : 0.0;
+        return 1;
+    }
+    v = (long double)sig;
+    if (extra_digits > 0) {
+        v = v * tg3json__pow10_ld(extra_digits) + extra;
+    }
+    if (exp10 != 0) v *= tg3json__pow10_ld(exp10);
+    if (neg) v = -v;
+    *out = (double)v;
+    if (tg3json__is_inf_bits(tg3json__double_bits(*out))) return 0;
+    return 1;
+}
+
+static char *tg3json__write_exp(char *p, int exp10) {
+    char tmp[16];
+    size_t n;
+    *p++ = 'e';
+    if (exp10 < 0) {
+        *p++ = '-';
+        exp10 = -exp10;
+    }
+    n = tg3json__utoa((uint64_t)exp10, tmp);
+    TINYGLTF_JSON_MEMCPY(p, tmp, n);
+    return p + n;
+}
+
+static char *tg3json__format_decimal_digits(char *out, const char *digits,
+                                            int ndigits, int dec_exp,
+                                            int negative) {
+    char *p = out;
+    int i;
+    int output_exp = dec_exp + ndigits - 1;
+    if (negative) *p++ = '-';
+    if (output_exp < -4 || output_exp >= 16) {
+        *p++ = digits[0];
+        if (ndigits > 1) {
+            *p++ = '.';
+            for (i = 1; i < ndigits; ++i) *p++ = digits[i];
+        }
+        return tg3json__write_exp(p, output_exp);
+    }
+    if (dec_exp >= 0) {
+        for (i = 0; i < ndigits; ++i) *p++ = digits[i];
+        for (i = 0; i < dec_exp; ++i) *p++ = '0';
+        return p;
+    }
+    if (dec_exp + ndigits > 0) {
+        int int_digits = dec_exp + ndigits;
+        for (i = 0; i < int_digits; ++i) *p++ = digits[i];
+        *p++ = '.';
+        for (; i < ndigits; ++i) *p++ = digits[i];
+        return p;
+    }
+    *p++ = '0';
+    *p++ = '.';
+    for (i = 0; i < -(dec_exp + ndigits); ++i) *p++ = '0';
+    for (i = 0; i < ndigits; ++i) *p++ = digits[i];
+    return p;
+}
+
+static int tg3json__same_f64(double a, double b) {
+    return tg3json__double_bits(a) == tg3json__double_bits(b);
+}
+
+static char *tg3json__dtoa_c(double value, char *buf) {
+    uint64_t bits = tg3json__double_bits(value);
+    int negative = (int)(bits >> 63);
+    uint64_t abits = bits & 0x7fffffffffffffffULL;
+    long double x;
+    int dec_e = 0;
+    char digits[24];
+    int ndigits = 17;
+    int i;
+    char best[80];
+    size_t best_len;
+
+    if (tg3json__is_nan_bits(bits)) {
+        TINYGLTF_JSON_MEMCPY(buf, "nan", 3);
+        return buf + 3;
+    }
+    if (tg3json__is_inf_bits(bits)) {
+        if (negative) {
+            TINYGLTF_JSON_MEMCPY(buf, "-inf", 4);
+            return buf + 4;
+        }
+        TINYGLTF_JSON_MEMCPY(buf, "inf", 3);
+        return buf + 3;
+    }
+    if (abits == 0) {
+        *buf++ = '0';
+        return buf;
+    }
+    if (bits == 0x3ff0000000000000ULL) {
+        *buf++ = '1';
+        return buf;
+    }
+    if (bits == 0xbff0000000000000ULL) {
+        *buf++ = '-';
+        *buf++ = '1';
+        return buf;
+    }
+
+    x = negative ? -(long double)value : (long double)value;
+    while (x >= 1.0e16L) {
+        x *= 1.0e-16L;
+        dec_e += 16;
+    }
+    while (x >= 10.0L) {
+        x *= 0.1L;
+        ++dec_e;
+    }
+    while (x < 1.0L) {
+        x *= 10.0L;
+        --dec_e;
+    }
+    for (i = 0; i < 18; ++i) {
+        int d = (int)x;
+        if (d < 0) d = 0;
+        if (d > 9) d = 9;
+        digits[i] = (char)('0' + d);
+        x = (x - (long double)d) * 10.0L;
+    }
+    if (digits[17] >= '5') {
+        int carry = 1;
+        for (i = 16; i >= 0 && carry; --i) {
+            if (digits[i] == '9') {
+                digits[i] = '0';
+            } else {
+                digits[i]++;
+                carry = 0;
+            }
+        }
+        if (carry) {
+            digits[0] = '1';
+            for (i = 1; i < 17; ++i) digits[i] = '0';
+            ++dec_e;
+        }
+    }
+    while (ndigits > 1 && digits[ndigits - 1] == '0') --ndigits;
+
+    {
+        char *end = tg3json__format_decimal_digits(best, digits, ndigits,
+                                                   dec_e - ndigits + 1,
+                                                   negative);
+        *end = '\0';
+        best_len = (size_t)(end - best);
+    }
+    for (i = ndigits - 1; i >= 1; --i) {
+        char candidate[80];
+        char *end;
+        double parsed = 0.0;
+        end = tg3json__format_decimal_digits(candidate, digits, i,
+                                             dec_e - i + 1, negative);
+        *end = '\0';
+        if (tg3json__parse_f64_c(candidate, end, &parsed) &&
+            tg3json__same_f64(parsed, value)) {
+            TINYGLTF_JSON_MEMCPY(best, candidate, (size_t)(end - candidate) + 1);
+            best_len = (size_t)(end - candidate);
+        } else {
+            break;
+        }
+    }
+    TINYGLTF_JSON_MEMCPY(buf, best, best_len);
+    return buf + best_len;
+}
 
 typedef struct tg3json__parser {
     const char *cur;
@@ -136,27 +575,27 @@ typedef struct tg3json__buffer {
 
 static void tg3json__init_value(tg3json_value *value) {
     if (!value) return;
-    memset(value, 0, sizeof(*value));
+    TINYGLTF_JSON_MEMSET(value, 0, sizeof(*value));
     value->type = TG3JSON_NULL;
 }
 
 static char *tg3json__strndup_local(const char *src, size_t len) {
-    char *dst = (char *)malloc(len + 1);
+    char *dst = (char *)TINYGLTF_JSON_MALLOC(len + 1);
     if (!dst) return NULL;
-    if (len > 0) memcpy(dst, src, len);
+    if (len > 0) TINYGLTF_JSON_MEMCPY(dst, src, len);
     dst[len] = '\0';
     return dst;
 }
 
 static void *tg3json__parser_alloc(tg3json__parser *parser, size_t size) {
     void *ptr;
-    if (!parser) return malloc(size);
+    if (!parser) return TINYGLTF_JSON_MALLOC(size);
     if (parser->max_single_alloc && size > parser->max_single_alloc) return NULL;
     if (parser->memory_budget &&
         (size > parser->memory_budget || parser->allocated > parser->memory_budget - size)) {
         return NULL;
     }
-    ptr = malloc(size);
+    ptr = TINYGLTF_JSON_MALLOC(size);
     if (!ptr) return NULL;
     parser->allocated += size;
     return ptr;
@@ -178,7 +617,7 @@ static int tg3json__reserve_bytes(void **ptr, size_t elem_size,
     }
 
     if (elem_size != 0 && new_cap > ((size_t)-1) / elem_size) return 0;
-    new_ptr = realloc(*ptr, elem_size * new_cap);
+    new_ptr = TINYGLTF_JSON_REALLOC(*ptr, elem_size * new_cap);
     if (!new_ptr) return 0;
     *ptr = new_ptr;
     *capacity = new_cap;
@@ -215,7 +654,7 @@ static int tg3json__reserve_bytes_parser(tg3json__parser *parser, void **ptr,
             return 0;
         }
     }
-    new_ptr = realloc(*ptr, new_bytes);
+    new_ptr = TINYGLTF_JSON_REALLOC(*ptr, new_bytes);
     if (!new_ptr) return 0;
     if (parser && new_bytes > old_bytes) parser->allocated += new_bytes - old_bytes;
     *ptr = new_ptr;
@@ -242,7 +681,7 @@ static int tg3json__buf_append(tg3json__buffer *buf, const char *src, size_t len
                                        buf->len + len + 1, &buf->cap)) {
         return 0;
     }
-    memcpy(buf->data + buf->len, src, len);
+    TINYGLTF_JSON_MEMCPY(buf->data + buf->len, src, len);
     buf->len += len;
     buf->data[buf->len] = '\0';
     return 1;
@@ -300,7 +739,7 @@ static int tg3json__parse_string_raw(tg3json__parser *parser,
                                      char **out_str, size_t *out_len) {
     tg3json__buffer buf;
     const char *start;
-    memset(&buf, 0, sizeof(buf));
+    TINYGLTF_JSON_MEMSET(&buf, 0, sizeof(buf));
     buf.parser = parser;
 
     if (parser->cur >= parser->end || *parser->cur != '"') {
@@ -356,7 +795,7 @@ static int tg3json__parse_string_raw(tg3json__parser *parser,
                 }
                 default:
                     tg3json__set_error(parser, parser->cur);
-                    free(buf.data);
+                    TINYGLTF_JSON_FREE(buf.data);
                     return 0;
             }
             ++parser->cur;
@@ -368,12 +807,12 @@ static int tg3json__parse_string_raw(tg3json__parser *parser,
     }
 
     tg3json__set_error(parser, parser->cur);
-    free(buf.data);
+    TINYGLTF_JSON_FREE(buf.data);
     return 0;
 
 oom:
     tg3json__set_error(parser, parser->cur);
-    free(buf.data);
+    TINYGLTF_JSON_FREE(buf.data);
     return 0;
 }
 
@@ -456,7 +895,7 @@ fail:
         --count;
         tg3json_value_free(&items[count]);
     }
-    free(items);
+    TINYGLTF_JSON_FREE(items);
     tg3json__set_error(parser, parser->cur);
     return 0;
 
@@ -465,7 +904,7 @@ oom:
         --count;
         tg3json_value_free(&items[count]);
     }
-    free(items);
+    TINYGLTF_JSON_FREE(items);
     tg3json__set_error(parser, parser->cur);
     return 0;
 }
@@ -494,18 +933,18 @@ static int tg3json__parse_object(tg3json__parser *parser, size_t depth,
         if (!tg3json__parse_string_raw(parser, &key, &key_len)) goto fail;
         parser->cur = tg3json__skip_ws(parser->cur, parser->end);
         if (parser->cur >= parser->end || *parser->cur != ':') {
-            free(key);
+            TINYGLTF_JSON_FREE(key);
             goto fail;
         }
         ++parser->cur;
         parser->cur = tg3json__skip_ws(parser->cur, parser->end);
         if (!tg3json__parse_value(parser, depth + 1, &value)) {
-            free(key);
+            TINYGLTF_JSON_FREE(key);
             goto fail;
         }
         if (!tg3json__reserve_bytes_parser(parser, (void **)&items,
                                            sizeof(*items), count + 1, &cap)) {
-            free(key);
+            TINYGLTF_JSON_FREE(key);
             tg3json_value_free(&value);
             goto oom;
         }
@@ -513,7 +952,7 @@ static int tg3json__parse_object(tg3json__parser *parser, size_t depth,
         items[count].key_len = key_len;
         items[count].value = (tg3json_value *)tg3json__parser_alloc(parser, sizeof(tg3json_value));
         if (!items[count].value) {
-            free(key);
+            TINYGLTF_JSON_FREE(key);
             tg3json_value_free(&value);
             goto oom;
         }
@@ -539,26 +978,26 @@ static int tg3json__parse_object(tg3json__parser *parser, size_t depth,
 fail:
     while (count > 0) {
         --count;
-        free(items[count].key);
+        TINYGLTF_JSON_FREE(items[count].key);
         if (items[count].value) {
             tg3json_value_free(items[count].value);
-            free(items[count].value);
+            TINYGLTF_JSON_FREE(items[count].value);
         }
     }
-    free(items);
+    TINYGLTF_JSON_FREE(items);
     tg3json__set_error(parser, parser->cur);
     return 0;
 
 oom:
     while (count > 0) {
         --count;
-        free(items[count].key);
+        TINYGLTF_JSON_FREE(items[count].key);
         if (items[count].value) {
             tg3json_value_free(items[count].value);
-            free(items[count].value);
+            TINYGLTF_JSON_FREE(items[count].value);
         }
     }
-    free(items);
+    TINYGLTF_JSON_FREE(items);
     tg3json__set_error(parser, parser->cur);
     return 0;
 }
@@ -567,9 +1006,6 @@ static int tg3json__parse_number(tg3json__parser *parser, tg3json_value *out_val
     const char *start = parser->cur;
     const char *p = parser->cur;
     int is_real = 0;
-    size_t len;
-    char stack_buf[128];
-    char *num_buf = stack_buf;
 
     if (*p == '-') ++p;
     if (p >= parser->end) goto fail;
@@ -605,59 +1041,55 @@ static int tg3json__parse_number(tg3json__parser *parser, tg3json_value *out_val
         is_real = 1;
     }
 
-    len = (size_t)(p - start);
-    if (len + 1 > sizeof(stack_buf)) {
-        num_buf = (char *)tg3json__parser_alloc(parser, len + 1);
-        if (!num_buf) goto oom;
-    }
-    memcpy(num_buf, start, len);
-    num_buf[len] = '\0';
-
     {
-        char *endptr = NULL;
-        errno = 0;
-        out_value->u.real = strtod(num_buf, &endptr);
-        if (endptr != num_buf + len) {
-            if (num_buf != stack_buf) free(num_buf);
-            goto fail;
-        }
+        if (!tg3json__parse_f64_c(start, p, &out_value->u.real)) goto fail;
         if (parser->parse_float32) out_value->u.real = (double)(float)out_value->u.real;
         out_value->type = TG3JSON_REAL;
         parser->cur = p;
-        if (num_buf != stack_buf) free(num_buf);
         return 1;
     }
 
 fail:
     tg3json__set_error(parser, parser->cur);
     return 0;
-oom:
-    tg3json__set_error(parser, parser->cur);
-    return 0;
 }
 
 static int tg3json__parse_value(tg3json__parser *parser, size_t depth,
                                 tg3json_value *out_value) {
-    tg3json__init_value(out_value);
-    if (depth > parser->depth_limit) {
+    if (parser->depth_limit && depth > parser->depth_limit) {
         tg3json__set_error(parser, parser->cur);
         return 0;
     }
+
     parser->cur = tg3json__skip_ws(parser->cur, parser->end);
     if (parser->cur >= parser->end) {
         tg3json__set_error(parser, parser->cur);
         return 0;
     }
+
     switch (*parser->cur) {
+        case '[':
+            return tg3json__parse_array(parser, depth, out_value);
+        case '{':
+            return tg3json__parse_object(parser, depth, out_value);
+        case '"': {
+            char *str = NULL;
+            size_t len = 0;
+            if (!tg3json__parse_string_raw(parser, &str, &len)) return 0;
+            out_value->type = TG3JSON_STRING;
+            out_value->u.string.ptr = str;
+            out_value->u.string.len = len;
+            return 1;
+        }
         case 'n':
-            if ((size_t)(parser->end - parser->cur) >= 4 && memcmp(parser->cur, "null", 4) == 0) {
+            if ((size_t)(parser->end - parser->cur) >= 4 && TINYGLTF_JSON_MEMCMP(parser->cur, "null", 4) == 0) {
                 out_value->type = TG3JSON_NULL;
                 parser->cur += 4;
                 return 1;
             }
             break;
         case 't':
-            if ((size_t)(parser->end - parser->cur) >= 4 && memcmp(parser->cur, "true", 4) == 0) {
+            if ((size_t)(parser->end - parser->cur) >= 4 && TINYGLTF_JSON_MEMCMP(parser->cur, "true", 4) == 0) {
                 out_value->type = TG3JSON_BOOL;
                 out_value->u.boolean = 1;
                 parser->cur += 4;
@@ -665,27 +1097,17 @@ static int tg3json__parse_value(tg3json__parser *parser, size_t depth,
             }
             break;
         case 'f':
-            if ((size_t)(parser->end - parser->cur) >= 5 && memcmp(parser->cur, "false", 5) == 0) {
+            if ((size_t)(parser->end - parser->cur) >= 5 && TINYGLTF_JSON_MEMCMP(parser->cur, "false", 5) == 0) {
                 out_value->type = TG3JSON_BOOL;
                 out_value->u.boolean = 0;
                 parser->cur += 5;
                 return 1;
             }
             break;
-        case '"':
-            out_value->type = TG3JSON_STRING;
-            return tg3json__parse_string_raw(parser, &out_value->u.string.ptr,
-                                             &out_value->u.string.len);
-        case '[':
-            return tg3json__parse_array(parser, depth, out_value);
-        case '{':
-            return tg3json__parse_object(parser, depth, out_value);
         default:
-            if (*parser->cur == '-' || (*parser->cur >= '0' && *parser->cur <= '9')) {
-                return tg3json__parse_number(parser, out_value);
-            }
-            break;
+            return tg3json__parse_number(parser, out_value);
     }
+
     tg3json__set_error(parser, parser->cur);
     return 0;
 }
@@ -695,40 +1117,50 @@ int tg3json_parse_n_opts(const char *data, size_t len,
                          tg3json_value *out_value,
                          const char **out_error_pos) {
     tg3json__parser parser;
-    if (!data || !out_value) {
-        if (out_error_pos) *out_error_pos = data;
-        return 0;
-    }
+    int ok;
+
+    if (out_error_pos) *out_error_pos = NULL;
+    if (!out_value) return 0;
     tg3json__init_value(out_value);
+    if (!data) return 0;
+
     parser.cur = data;
     parser.end = data + len;
     parser.error = NULL;
-    parser.depth_limit = (options && options->depth_limit) ? options->depth_limit : 512;
+    parser.depth_limit = options ? (options->depth_limit ? options->depth_limit : 256) : 256;
     parser.memory_budget = options ? options->memory_budget : 0;
     parser.max_single_alloc = options ? options->max_single_alloc : 0;
     parser.max_string_length = options ? options->max_string_length : 0;
     parser.allocated = 0;
     parser.parse_float32 = options ? options->parse_float32 : 0;
 
-    if (!tg3json__parse_value(&parser, 0, out_value)) {
-        if (out_error_pos) *out_error_pos = parser.error;
+    parser.cur = tg3json__skip_ws(parser.cur, parser.end);
+    if (parser.cur >= parser.end) {
+        if (out_error_pos) *out_error_pos = data;
+        return 0;
+    }
+
+    ok = tg3json__parse_value(&parser, 0, out_value);
+    if (!ok) {
+        if (out_error_pos) *out_error_pos = parser.error ? parser.error : parser.cur;
         tg3json_value_free(out_value);
         return 0;
     }
+
     parser.cur = tg3json__skip_ws(parser.cur, parser.end);
     if (parser.cur != parser.end) {
         if (out_error_pos) *out_error_pos = parser.cur;
         tg3json_value_free(out_value);
         return 0;
     }
-    if (out_error_pos) *out_error_pos = NULL;
+
     return 1;
 }
 
 int tg3json_parse_n(const char *data, size_t len, size_t depth_limit,
                     tg3json_value *out_value, const char **out_error_pos) {
     tg3json_parse_options options;
-    memset(&options, 0, sizeof(options));
+    TINYGLTF_JSON_MEMSET(&options, 0, sizeof(options));
     options.depth_limit = depth_limit;
     return tg3json_parse_n_opts(data, len, &options, out_value, out_error_pos);
 }
@@ -748,23 +1180,23 @@ void tg3json_value_free(tg3json_value *value) {
     if (!value) return;
     switch (value->type) {
         case TG3JSON_STRING:
-            free(value->u.string.ptr);
+            TINYGLTF_JSON_FREE(value->u.string.ptr);
             break;
         case TG3JSON_ARRAY:
             for (i = 0; i < value->u.array.count; ++i) {
                 tg3json_value_free(&value->u.array.items[i]);
             }
-            free(value->u.array.items);
+            TINYGLTF_JSON_FREE(value->u.array.items);
             break;
         case TG3JSON_OBJECT:
             for (i = 0; i < value->u.object.count; ++i) {
-                free(value->u.object.items[i].key);
+                TINYGLTF_JSON_FREE(value->u.object.items[i].key);
                 if (value->u.object.items[i].value) {
                     tg3json_value_free(value->u.object.items[i].value);
-                    free(value->u.object.items[i].value);
+                    TINYGLTF_JSON_FREE(value->u.object.items[i].value);
                 }
             }
-            free(value->u.object.items);
+            TINYGLTF_JSON_FREE(value->u.object.items);
             break;
         case TG3JSON_NULL:
         case TG3JSON_BOOL:
@@ -811,7 +1243,7 @@ int tg3json_value_init_string_n(tg3json_value *value, const char *str, size_t le
 }
 
 int tg3json_value_init_string(tg3json_value *value, const char *str) {
-    return tg3json_value_init_string_n(value, str, str ? strlen(str) : 0);
+    return tg3json_value_init_string_n(value, str, str ? TINYGLTF_JSON_STRLEN(str) : 0);
 }
 
 void tg3json_value_init_array(tg3json_value *value) {
@@ -872,7 +1304,7 @@ const tg3json_value *tg3json_object_get_n(const tg3json_value *object,
     if (!object || object->type != TG3JSON_OBJECT) return NULL;
     for (i = 0; i < object->u.object.count; ++i) {
         const tg3json_object_entry *entry = &object->u.object.items[i];
-        if (entry->key_len == key_len && memcmp(entry->key, key, key_len) == 0) {
+        if (entry->key_len == key_len && TINYGLTF_JSON_MEMCMP(entry->key, key, key_len) == 0) {
             return entry->value;
         }
     }
@@ -882,7 +1314,7 @@ const tg3json_value *tg3json_object_get_n(const tg3json_value *object,
 const tg3json_value *tg3json_object_get(const tg3json_value *object,
                                         const char *key) {
     if (!key) return NULL;
-    return tg3json_object_get_n(object, key, strlen(key));
+    return tg3json_object_get_n(object, key, TINYGLTF_JSON_STRLEN(key));
 }
 
 tg3json_value *tg3json_object_get_mut_n(tg3json_value *object,
@@ -891,7 +1323,7 @@ tg3json_value *tg3json_object_get_mut_n(tg3json_value *object,
     if (!object || object->type != TG3JSON_OBJECT) return NULL;
     for (i = 0; i < object->u.object.count; ++i) {
         tg3json_object_entry *entry = &object->u.object.items[i];
-        if (entry->key_len == key_len && memcmp(entry->key, key, key_len) == 0) {
+        if (entry->key_len == key_len && TINYGLTF_JSON_MEMCMP(entry->key, key, key_len) == 0) {
             return entry->value;
         }
     }
@@ -900,7 +1332,7 @@ tg3json_value *tg3json_object_get_mut_n(tg3json_value *object,
 
 tg3json_value *tg3json_object_get_mut(tg3json_value *object, const char *key) {
     if (!key) return NULL;
-    return tg3json_object_get_mut_n(object, key, strlen(key));
+    return tg3json_object_get_mut_n(object, key, TINYGLTF_JSON_STRLEN(key));
 }
 
 const tg3json_object_entry *tg3json_object_at(const tg3json_value *object,
@@ -938,9 +1370,9 @@ int tg3json_object_set_take_n(tg3json_value *object, const char *key, size_t key
     entry->key = tg3json__strndup_local(key, key_len);
     if (!entry->key) return 0;
     entry->key_len = key_len;
-    entry->value = (tg3json_value *)malloc(sizeof(tg3json_value));
+    entry->value = (tg3json_value *)TINYGLTF_JSON_MALLOC(sizeof(tg3json_value));
     if (!entry->value) {
-        free(entry->key);
+        TINYGLTF_JSON_FREE(entry->key);
         entry->key = NULL;
         entry->key_len = 0;
         return 0;
@@ -954,7 +1386,7 @@ int tg3json_object_set_take_n(tg3json_value *object, const char *key, size_t key
 int tg3json_object_set_take(tg3json_value *object, const char *key,
                             tg3json_value *value) {
     if (!key) return 0;
-    return tg3json_object_set_take_n(object, key, strlen(key), value);
+    return tg3json_object_set_take_n(object, key, TINYGLTF_JSON_STRLEN(key), value);
 }
 
 int tg3json_object_set_copy_n(tg3json_value *object, const char *key, size_t key_len,
@@ -972,7 +1404,7 @@ int tg3json_object_set_copy_n(tg3json_value *object, const char *key, size_t key
 int tg3json_object_set_copy(tg3json_value *object, const char *key,
                             const tg3json_value *value) {
     if (!key) return 0;
-    return tg3json_object_set_copy_n(object, key, strlen(key), value);
+    return tg3json_object_set_copy_n(object, key, TINYGLTF_JSON_STRLEN(key), value);
 }
 
 const tg3json_value *tg3json_array_get(const tg3json_value *array, size_t index) {
@@ -1032,26 +1464,19 @@ static int tg3json__stringify_value_ex(tg3json__buffer *buf, const tg3json_value
             return value->u.boolean ? tg3json__buf_append(buf, "true", 4)
                                     : tg3json__buf_append(buf, "false", 5);
         case TG3JSON_INT:
-            snprintf(numbuf, sizeof(numbuf), "%lld", (long long)value->u.integer);
-            return tg3json__buf_append(buf, numbuf, strlen(numbuf));
+            tg3json__itoa(value->u.integer, numbuf);
+            return tg3json__buf_append(buf, numbuf, TINYGLTF_JSON_STRLEN(numbuf));
         case TG3JSON_REAL:
-            snprintf(numbuf, sizeof(numbuf), "%.17g", value->u.real);
             {
+                char *end = tg3json__dtoa_c(value->u.real, numbuf);
+                *end = '\0';
                 const char *b = numbuf;
                 if (*b == '-') ++b;
                 if (*b == 'n' || *b == 'N' || *b == 'i' || *b == 'I') {
                     return tg3json__buf_append(buf, "null", 4);
                 }
             }
-            if (!strchr(numbuf, '.') && !strchr(numbuf, 'e') && !strchr(numbuf, 'E')) {
-                size_t nlen = strlen(numbuf);
-                if (nlen + 2 < sizeof(numbuf)) {
-                    numbuf[nlen] = '.';
-                    numbuf[nlen + 1] = '0';
-                    numbuf[nlen + 2] = '\0';
-                }
-            }
-            return tg3json__buf_append(buf, numbuf, strlen(numbuf));
+            return tg3json__buf_append(buf, numbuf, TINYGLTF_JSON_STRLEN(numbuf));
         case TG3JSON_STRING:
             if (!tg3json__buf_putc(buf, '"')) return 0;
             for (i = 0; i < value->u.string.len; ++i) {
@@ -1066,7 +1491,13 @@ static int tg3json__stringify_value_ex(tg3json__buffer *buf, const tg3json_value
                     case '\t': if (!tg3json__buf_append(buf, "\\t", 2)) return 0; break;
                     default:
                         if (c < 0x20u) {
-                            snprintf(numbuf, sizeof(numbuf), "\\u%04x", (unsigned int)c);
+                            numbuf[0] = '\\';
+                            numbuf[1] = 'u';
+                            numbuf[2] = '0';
+                            numbuf[3] = '0';
+                            numbuf[4] = "0123456789abcdef"[(c >> 4) & 0xf];
+                            numbuf[5] = "0123456789abcdef"[c & 0xf];
+                            numbuf[6] = '\0';
                             if (!tg3json__buf_append(buf, numbuf, 6)) return 0;
                         } else {
                             if (!tg3json__buf_putc(buf, (char)c)) return 0;
@@ -1107,14 +1538,14 @@ static int tg3json__stringify_value_ex(tg3json__buffer *buf, const tg3json_value
 
 char *tg3json_stringify(const tg3json_value *value, size_t *out_len) {
     tg3json__buffer buf;
-    memset(&buf, 0, sizeof(buf));
+    TINYGLTF_JSON_MEMSET(&buf, 0, sizeof(buf));
     if (!value || !tg3json__stringify_value_ex(&buf, value, -1, 0)) {
-        free(buf.data);
+        TINYGLTF_JSON_FREE(buf.data);
         if (out_len) *out_len = 0;
         return NULL;
     }
     if (!buf.data) {
-        buf.data = (char *)malloc(1);
+        buf.data = (char *)TINYGLTF_JSON_MALLOC(1);
         if (!buf.data) {
             if (out_len) *out_len = 0;
             return NULL;
@@ -1127,14 +1558,14 @@ char *tg3json_stringify(const tg3json_value *value, size_t *out_len) {
 
 char *tg3json_stringify_pretty(const tg3json_value *value, int indent, size_t *out_len) {
     tg3json__buffer buf;
-    memset(&buf, 0, sizeof(buf));
+    TINYGLTF_JSON_MEMSET(&buf, 0, sizeof(buf));
     if (!value || !tg3json__stringify_value_ex(&buf, value, indent, 0)) {
-        free(buf.data);
+        TINYGLTF_JSON_FREE(buf.data);
         if (out_len) *out_len = 0;
         return NULL;
     }
     if (!buf.data) {
-        buf.data = (char *)malloc(1);
+        buf.data = (char *)TINYGLTF_JSON_MALLOC(1);
         if (!buf.data) {
             if (out_len) *out_len = 0;
             return NULL;