Fix overflow area of hash table in palette generation

aaaaaa123456789 · Jan 9, 2022 · 3395882 · 3395882
1 parent 1c4d068
commit 3395882
Show file tree

Hide file tree

Showing 2 changed files with 3 additions and 2 deletions.
diff --git a/docs/changelog.md b/docs/changelog.md
@@ -8,6 +8,7 @@ Note: releases are listed from latest to oldest.
 - Added a missing check for an extremely unlikely memory allocation failure
 - Fixed some BMP encoding bugs that could arise under unusual circumstances
 - Fixed BMP decoder to accept images that are exactly `0x7fffffff` pixels tall or wide
+- Fixed palette generation for images with many similar colors
 - Updated the tutorial to use `plum_append_metadata` where relevant
 - Some refactorings and minor documentation changes
 

diff --git a/src/palette.c b/src/palette.c
@@ -167,14 +167,14 @@ int plum_convert_colors_to_indexes (uint8_t * restrict destination, const void *
       counts[hash] ++;
       total ++;
     } else {
-      for (p = hash; counts[p] & 0x80; p ++) {
+      for (p = hash; counts[p] & 0x80; p = (p + 1) & 0xff) {
         index = (p << 3) | 7;
         if (colors[index] == color) goto found;
       }
       if (total >= 0x100) goto done;
       index = (p << 3) | 7;
       colors[index] = color;
-      counts[hash] |= 0x80;
+      counts[p] |= 0x80;
       total ++;
     }
     found: