Add tests/v3/fuzzer/ with libFuzzer harness covering all four parse
paths (auto-detect, JSON, GLB, float32 mode) with ASan+UBSan.
Fix two bugs found by 10+ hours of fuzzing (~23M iterations):
1. UB: (int64_t)inf in cj_parse_number when extreme exponents like
22222222e222222 produce infinity. Add cj_dbl_to_i64() that clamps
inf/NaN/out-of-range values before casting.
2. Null deref in tg3__parse_string when glTF array elements are not
JSON objects (e.g. "scenes": [[3]]). Add is_object() validation
in TG3__PARSE_ARRAY_SIMPLE and TG3__PARSE_ARRAY_IDX macros.
Verified clean: 5.8M additional runs with zero crashes after fixes.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Replace strtod() with Clinger's fast path in tinygltf_json.h for ~1.5x
faster JSON float parsing. The new parser accumulates all digits into a
uint64 mantissa and uses exact power-of-10 tables for conversion,
avoiding locale-dependent strtod for ~99% of JSON float values.
Add optional float32 parse mode (parse_float32 option) that parses JSON
floats at single precision — fewer significant digits needed, wider fast
path range. Breaks strict double-precision conformance but sufficient
for glTF data which is typically single-precision.
Benchmark additions:
- gen_synthetic: add float_heavy preset (~500MB ASCII float JSON)
- bench_v3: add --float32 flag for float32 parse mode benchmarking
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
