From b97308683b042d77f63a01138cf0167ba78a3137 Mon Sep 17 00:00:00 2001
From: yurik <yurik@bluemarblegeo.com>
Date: Sat, 31 May 2025 03:05:44 -0400
Subject: [PATCH] Fix a bug in importing binary PLY file (#1) (#6060)

* Correct IOStreamBuffer<T>::getNextLine() to prevent skipping too many '\n', which could be part of the BINARY part
* Add a regression test
---
 include/assimp/IOStreamBuffer.h               |   5 ++++-
 .../models/PLY/cube_binary_starts_with_nl.ply | Bin 0 -> 451 bytes
 test/unit/utPLYImportExport.cpp               |  21 ++++++++++++++++++
 3 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100644 test/models/PLY/cube_binary_starts_with_nl.ply

diff --git a/include/assimp/IOStreamBuffer.h b/include/assimp/IOStreamBuffer.h
index ca2db9c4d..29b7cf317 100644
--- a/include/assimp/IOStreamBuffer.h
+++ b/include/assimp/IOStreamBuffer.h
@@ -318,7 +318,10 @@ AI_FORCE_INLINE bool IOStreamBuffer<T>::getNextLine(std::vector<T> &buffer) {
         }
     }
     buffer[i] = '\n';
-    while (m_cachePos < m_cacheSize && (m_cache[m_cachePos] == '\r' || m_cache[m_cachePos] == '\n')) {
+    if (m_cachePos < m_cacheSize && (m_cache[m_cachePos] == '\r')) {
+        ++m_cachePos;
+    }
+    if (m_cachePos < m_cacheSize && (m_cache[m_cachePos] == '\n')) {
         ++m_cachePos;
     }
 
diff --git a/test/models/PLY/cube_binary_starts_with_nl.ply b/test/models/PLY/cube_binary_starts_with_nl.ply
new file mode 100644
index 0000000000000000000000000000000000000000..0eed84a5c26eb916e4ac9b6908bf5b60d2f70476
GIT binary patch
literal 451
zcmZ8cK~BRk5Ht`#@+<ZT2U6NXAzTXLgj9(qL{73%EIE$lm@47am+=&y(KEYgL#tYv
z@$7nbY&+A-vhlSFkZG%YpBf#4!4z$wm4#`1FY~6Z(FS<;r~(#{_3-J?!du&7fREZW
zKEO(6p2p!0su0}EWTM(u*Dh|$*plmJ{TM&Q^V!oPnNMd)ax2l`kh(@6u!CpmeB(&>
zP@0CG)15Z@)5iCIMyYay#o^rOHo#Y2DG!<+zPlpTw!lu($I=Q_fnLh(&#Tz4gWfE6
zdb1SbSPLPyzeoO2vxoKQAGHt>XP*(y2^WOun&^sf$;BRn;08M*CN9{;V-XV<JUV1B
JaWSOR{s$hjZ}|WK

literal 0
HcmV?d00001

diff --git a/test/unit/utPLYImportExport.cpp b/test/unit/utPLYImportExport.cpp
index 0dc4b1b76..630d38d35 100644
--- a/test/unit/utPLYImportExport.cpp
+++ b/test/unit/utPLYImportExport.cpp
@@ -141,6 +141,27 @@ TEST_F(utPLYImportExport, importBinaryPLYWithRNNewline) {
     EXPECT_EQ(2u, scene->mMeshes[0]->mFaces[0].mIndices[2]);
 }
 
+// Tests of a PLY file gets read with \n as the fist character in the BINARY part
+TEST_F(utPLYImportExport, importBinaryPLYWithNewlineInBinary) {
+    Assimp::Importer importer;
+    const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/PLY/cube_binary_starts_with_nl.ply", aiProcess_ValidateDataStructure);
+
+    ASSERT_NE(nullptr, scene);
+    ASSERT_NE(nullptr, scene->mMeshes[0]);
+    ASSERT_EQ(8u, scene->mMeshes[0]->mNumVertices);
+    // Make sure the first binary float was read correctly
+    ASSERT_FLOAT_EQ(5.967534f, scene->mMeshes[0]->mVertices[0][0]);
+    ASSERT_FLOAT_EQ(0, scene->mMeshes[0]->mVertices[0][1]);
+    ASSERT_FLOAT_EQ(0, scene->mMeshes[0]->mVertices[0][2]);
+
+    ASSERT_EQ(6u, scene->mMeshes[0]->mNumFaces);
+    // Also check if the indices were parsed correctly
+    ASSERT_EQ(4u, scene->mMeshes[0]->mFaces[0].mNumIndices);
+    EXPECT_EQ(0u, scene->mMeshes[0]->mFaces[0].mIndices[0]);
+    EXPECT_EQ(1u, scene->mMeshes[0]->mFaces[0].mIndices[1]);
+    EXPECT_EQ(2u, scene->mMeshes[0]->mFaces[0].mIndices[2]);
+}
+
 TEST_F(utPLYImportExport, vertexColorTest) {
     Assimp::Importer importer;
     const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/PLY/float-color.ply", aiProcess_ValidateDataStructure);