1 files changed, 25 insertions, 28 deletions

diff --git a/thirdparty/libwebp/src/mux/muxinternal.c b/thirdparty/libwebp/src/mux/muxinternal.c
index 1473f100e5..b9ee6717d3 100644
--- a/thirdparty/libwebp/src/mux/muxinternal.c
+++ b/thirdparty/libwebp/src/mux/muxinternal.c
@@ -111,27 +111,6 @@ WebPChunk* ChunkSearchList(WebPChunk* first, uint32_t nth, uint32_t tag) {
   return ((nth > 0) && (iter > 0)) ? NULL : first;
 }
 
-// Outputs a pointer to 'prev_chunk->next_',
-//   where 'prev_chunk' is the pointer to the chunk at position (nth - 1).
-// Returns true if nth chunk was found.
-static int ChunkSearchListToSet(WebPChunk** chunk_list, uint32_t nth,
-                                WebPChunk*** const location) {
-  uint32_t count = 0;
-  assert(chunk_list != NULL);
-  *location = chunk_list;
-
-  while (*chunk_list != NULL) {
-    WebPChunk* const cur_chunk = *chunk_list;
-    ++count;
-    if (count == nth) return 1;  // Found.
-    chunk_list = &cur_chunk->next_;
-    *location = chunk_list;
-  }
-
-  // *chunk_list is ok to be NULL if adding at last location.
-  return (nth == 0 || (count == nth - 1)) ? 1 : 0;
-}
-
 //------------------------------------------------------------------------------
 // Chunk writer methods.
 
@@ -156,11 +135,12 @@ WebPMuxError ChunkAssignData(WebPChunk* chunk, const WebPData* const data,
   return WEBP_MUX_OK;
 }
 
-WebPMuxError ChunkSetNth(WebPChunk* chunk, WebPChunk** chunk_list,
-                         uint32_t nth) {
+WebPMuxError ChunkSetHead(WebPChunk* const chunk,
+                          WebPChunk** const chunk_list) {
   WebPChunk* new_chunk;
 
-  if (!ChunkSearchListToSet(chunk_list, nth, &chunk_list)) {
+  assert(chunk_list != NULL);
+  if (*chunk_list != NULL) {
     return WEBP_MUX_NOT_FOUND;
   }
 
@@ -168,11 +148,26 @@ WebPMuxError ChunkSetNth(WebPChunk* chunk, WebPChunk** chunk_list,
   if (new_chunk == NULL) return WEBP_MUX_MEMORY_ERROR;
   *new_chunk = *chunk;
   chunk->owner_ = 0;
-  new_chunk->next_ = *chunk_list;
+  new_chunk->next_ = NULL;
   *chunk_list = new_chunk;
   return WEBP_MUX_OK;
 }
 
+WebPMuxError ChunkAppend(WebPChunk* const chunk,
+                         WebPChunk*** const chunk_list) {
+  assert(chunk_list != NULL && *chunk_list != NULL);
+
+  if (**chunk_list == NULL) {
+    ChunkSetHead(chunk, *chunk_list);
+  } else {
+    WebPChunk* last_chunk = **chunk_list;
+    while (last_chunk->next_ != NULL) last_chunk = last_chunk->next_;
+    ChunkSetHead(chunk, &last_chunk->next_);
+    *chunk_list = &last_chunk->next_;
+  }
+  return WEBP_MUX_OK;
+}
+
 //------------------------------------------------------------------------------
 // Chunk deletion method(s).
 
@@ -232,9 +227,11 @@ void MuxImageInit(WebPMuxImage* const wpi) {
 WebPMuxImage* MuxImageRelease(WebPMuxImage* const wpi) {
   WebPMuxImage* next;
   if (wpi == NULL) return NULL;
-  ChunkDelete(wpi->header_);
-  ChunkDelete(wpi->alpha_);
-  ChunkDelete(wpi->img_);
+  // There should be at most one chunk of header_, alpha_, img_ but we call
+  // ChunkListDelete to be safe
+  ChunkListDelete(&wpi->header_);
+  ChunkListDelete(&wpi->alpha_);
+  ChunkListDelete(&wpi->img_);
   ChunkListDelete(&wpi->unknown_);
 
   next = wpi->next_;