Use (MIN/NUM)_(TRANSFORM/HUFFMAN)_BITS where appropriate

Change-Id: I849ff8864f7abcc723dfe2b7ee0f290c8ee89c3f
webmproject · May 6, 2024 · 64d1ec2 · 64d1ec2
1 parent a90160e
commit 64d1ec2
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Showing 3 changed files with 17 additions and 9 deletions.
diff --git a/src/dec/vp8l_dec.c b/src/dec/vp8l_dec.c
@@ -20,10 +20,9 @@
 #include "src/dsp/dsp.h"
 #include "src/dsp/lossless.h"
 #include "src/dsp/lossless_common.h"
-#include "src/dsp/yuv.h"
-#include "src/utils/endian_inl_utils.h"
 #include "src/utils/huffman_utils.h"
 #include "src/utils/utils.h"
+#include "src/webp/format_constants.h"
 
 #define NUM_ARGB_CACHE_ROWS          16
 
@@ -381,7 +380,8 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
 
   if (allow_recursion && VP8LReadBits(br, 1)) {
     // use meta Huffman codes.
-    const int huffman_precision = VP8LReadBits(br, 3) + 2;
+    const int huffman_precision =
+        MIN_HUFFMAN_BITS + VP8LReadBits(br, NUM_HUFFMAN_BITS);
     const int huffman_xsize = VP8LSubSampleSize(xsize, huffman_precision);
     const int huffman_ysize = VP8LSubSampleSize(ysize, huffman_precision);
     const int huffman_pixs = huffman_xsize * huffman_ysize;
@@ -1351,7 +1351,8 @@ static int ReadTransform(int* const xsize, int const* ysize,
   switch (type) {
     case PREDICTOR_TRANSFORM:
     case CROSS_COLOR_TRANSFORM:
-      transform->bits_ = VP8LReadBits(br, 3) + 2;
+      transform->bits_ =
+          MIN_TRANSFORM_BITS + VP8LReadBits(br, NUM_TRANSFORM_BITS);
       ok = DecodeImageStream(VP8LSubSampleSize(transform->xsize_,
                                                transform->bits_),
                              VP8LSubSampleSize(transform->ysize_,

diff --git a/src/enc/vp8l_enc.c b/src/enc/vp8l_enc.c
@@ -30,6 +30,7 @@
 
 // Maximum number of histogram images (sub-blocks).
 #define MAX_HUFF_IMAGE_SIZE       2600
+#define MAX_HUFFMAN_BITS (MIN_HUFFMAN_BITS + (1 << NUM_HUFFMAN_BITS) - 1)
 
 // -----------------------------------------------------------------------------
 // Palette
@@ -1083,8 +1084,8 @@ static int ApplyPredictFilter(VP8LEncoder* const enc, int width, int height,
   }
   VP8LPutBits(bw, TRANSFORM_PRESENT, 1);
   VP8LPutBits(bw, PREDICTOR_TRANSFORM, 2);
-  assert(pred_bits >= 2);
-  VP8LPutBits(bw, pred_bits - 2, 3);
+  assert(pred_bits >= MIN_TRANSFORM_BITS);
+  VP8LPutBits(bw, pred_bits - MIN_TRANSFORM_BITS, NUM_TRANSFORM_BITS);
   return EncodeImageNoHuffman(
       bw, enc->transform_data_, (VP8LHashChain*)&enc->hash_chain_,
       (VP8LBackwardRefs*)&enc->refs_[0], transform_width, transform_height,
@@ -1107,8 +1108,9 @@ static int ApplyCrossColorFilter(const VP8LEncoder* const enc, int width,
   }
   VP8LPutBits(bw, TRANSFORM_PRESENT, 1);
   VP8LPutBits(bw, CROSS_COLOR_TRANSFORM, 2);
-  assert(ccolor_transform_bits >= 2);
-  VP8LPutBits(bw, ccolor_transform_bits - 2, 3);
+  assert(ccolor_transform_bits >= MIN_TRANSFORM_BITS);
+  VP8LPutBits(bw, ccolor_transform_bits - MIN_TRANSFORM_BITS,
+              NUM_TRANSFORM_BITS);
   return EncodeImageNoHuffman(
       bw, enc->transform_data_, (VP8LHashChain*)&enc->hash_chain_,
       (VP8LBackwardRefs*)&enc->refs_[0], transform_width, transform_height,

diff --git a/src/webp/format_constants.h b/src/webp/format_constants.h
@@ -46,7 +46,12 @@
 #define CODE_LENGTH_CODES            19
 
 #define MIN_HUFFMAN_BITS             2  // min number of Huffman bits
-#define MAX_HUFFMAN_BITS             9  // max number of Huffman bits
+#define NUM_HUFFMAN_BITS             3
+
+// the maximum number of bits defining a transform is
+// MIN_TRANSFORM_BITS + (1 << NUM_TRANSFORM_BITS) - 1
+#define MIN_TRANSFORM_BITS           2
+#define NUM_TRANSFORM_BITS           3
 
 #define TRANSFORM_PRESENT            1  // The bit to be written when next data
                                         // to be read is a transform.