Update libwebp to version 1.0.2

This resolves #939.

media/libwebp/AUTHORS

@@ -1,4 +1,5 @@
 Contributors:
+- Alan Browning (browning at google dot com)
 - Charles Munger (clm at google dot com)
 - Christian Duvivier (cduvivier at google dot com)
 - Djordje Pesut (djordje dot pesut at imgtec dot com)
@@ -6,9 +7,10 @@ Contributors:
 - James Zern (jzern at google dot com)
 - Jan Engelhardt (jengelh at medozas dot de)
 - Jehan (jehan at girinstud dot io)
-- Johann (johann dot koenig at duck dot com)
+- Johann Koenig (johann dot koenig at duck dot com)
 - Jovan Zelincevic (jovan dot zelincevic at imgtec dot com)
 - Jyrki Alakuijala (jyrki at google dot com)
+- Konstantin Ivlev (tomskside at gmail dot com)
 - Lode Vandevenne (lode at google dot com)
 - Lou Quillio (louquillio at google dot com)
 - Mans Rullgard (mans at mansr dot com)
@@ -37,3 +39,4 @@ Contributors:
 - Vincent Rabaud (vrabaud at google dot com)
 - Vlad Tsyrklevich (vtsyrklevich at chromium dot org)
 - Yang Zhang (yang dot zhang at arm dot com)
+- Yannis Guyon (yguyon at google dot com)

media/libwebp/NEWS

@@ -1,3 +1,23 @@
+- 1/14/2019: version 1.0.2
+  This is a binary compatible release.
+  * (Windows) unicode file support in the tools (linux and mac already had
+    support, issue #398)
+  * lossless encoder speedups
+  * lossy encoder speedup on ARM
+  * lossless multi-threaded security fix (chromium:917029)
+
+- 11/2/2018: version 1.0.1
+  This is a binary compatible release.
+  * lossless encoder speedups
+  * big-endian fix for alpha decoding (issue #393)
+  * gif2webp fix for loop count=65535 transcode (issue #382)
+  * further security related hardening in libwebp & libwebpmux
+    (issues #383, #385, #386, #387, #388, #391)
+    (oss-fuzz #9099, #9100, #9105, #9106, #9111, #9112, #9119, #9123, #9170,
+              #9178, #9179, #9183, #9186, #9191, #9364, #9417, #9496, #10349,
+              #10423, #10634, #10700, #10838, #10922, #11021, #11088, #11152)
+  * miscellaneous bug & build fixes (issues #381, #394, #396, #397, #400)
+
 - 4/2/2018: version 1.0.0
   This is a binary compatible release.
   * lossy encoder improvements to avoid chroma shifts in various circumstances

media/libwebp/README

@@ -4,7 +4,7 @@
           \__\__/\____/\_____/__/ ____  ___
                 / _/ /    \    \ /  _ \/ _/
                /  \_/   / /   \ \   __/  \__
-               \____/____/\_____/_____/____/v1.0.0
+               \____/____/\_____/_____/____/v1.0.2
 
 Description:
 ============
@@ -136,6 +136,8 @@ cmake -DWEBP_BUILD_CWEBP=ON -DWEBP_BUILD_DWEBP=ON ../
 
 or through your favorite interface (like ccmake or cmake-qt-gui).
 
+Use option -DWEBP_UNICODE=ON for Unicode support on Windows (with chcp 65001).
+
 Finally, once installed, you can also use WebP in your CMake project by doing:
 
 find_package(WebP)
@@ -402,12 +404,14 @@ Options are:
   -nofilter .... disable in-loop filtering
   -dither <int>  dithering strength (0..100), default=50
   -noalphadither disable alpha plane dithering
+  -usebgcolor .. display background color
   -mt .......... use multi-threading
   -info ........ print info
   -h ........... this help message
 
 Keyboard shortcuts:
   'c' ................ toggle use of color profile
+  'b' ................ toggle background color display
   'i' ................ overlay file information
   'd' ................ disable blending & disposal (debug)
   'q' / 'Q' / ESC .... quit
@@ -470,6 +474,9 @@ Per-frame options (only used for subsequent images input):
 example: img2webp -loop 2 in0.png -lossy in1.jpg
                   -d 80 in2.tiff -o out.webp
 
+Note: if a single file name is passed as the argument, the arguments will be
+tokenized from this file. The file name must not start with the character '-'.
+
 Animated GIF conversion:
 ========================
 Animated GIF files can be converted to WebP files with animation using the

media/libwebp/README.mux

@@ -1,7 +1,7 @@
           __   __  ____  ____  ____  __ __  _     __ __
          /  \\/  \/  _ \/  _ \/  _ \/  \  \/ \___/_ / _\
          \       /   __/  _  \   __/      /  /  (_/  /__
-          \__\__/\_____/_____/__/  \__//_/\_____/__/___/v1.0.0
+          \__\__/\_____/_____/__/  \__//_/\_____/__/___/v1.0.2
 
 
 Description:
@@ -211,6 +211,35 @@ Code example:
 For a detailed AnimEncoder API reference, please refer to the header file
 (src/webp/mux.h).
 
+AnimDecoder API:
+================
+This AnimDecoder API allows decoding (possibly) animated WebP images.
+
+Code Example:
+
+  WebPAnimDecoderOptions dec_options;
+  WebPAnimDecoderOptionsInit(&dec_options);
+  // Tune 'dec_options' as needed.
+  WebPAnimDecoder* dec = WebPAnimDecoderNew(webp_data, &dec_options);
+  WebPAnimInfo anim_info;
+  WebPAnimDecoderGetInfo(dec, &anim_info);
+  for (uint32_t i = 0; i < anim_info.loop_count; ++i) {
+    while (WebPAnimDecoderHasMoreFrames(dec)) {
+      uint8_t* buf;
+      int timestamp;
+      WebPAnimDecoderGetNext(dec, &buf, &timestamp);
+      // ... (Render 'buf' based on 'timestamp').
+      // ... (Do NOT free 'buf', as it is owned by 'dec').
+    }
+    WebPAnimDecoderReset(dec);
+  }
+  const WebPDemuxer* demuxer = WebPAnimDecoderGetDemuxer(dec);
+  // ... (Do something using 'demuxer'; e.g. get EXIF/XMP/ICC data).
+  WebPAnimDecoderDelete(dec);
+
+For a detailed AnimDecoder API reference, please refer to the header file
+(src/webp/demux.h).
+
 
 Bugs:
 =====

media/libwebp/UXPCHANGES

@@ -2,3 +2,4 @@ Changes made to pristine libwebp source by Moonchild Productions and mozilla.org
 
 2017/01/27  -- Synced with libwebp-0.6.0 (BZ #1294490).
 2018/06/29  -- Synced with libwebp-1.0.0 + BUG=webp:381,383,384.
+2019/01/21  -- Synced with libwebp-1.0.2

media/libwebp/dec/alphai_dec.h

@@ -51,4 +51,4 @@ void WebPDeallocateAlphaMemory(VP8Decoder* const dec);
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_DEC_ALPHAI_DEC_H_ */
+#endif  // WEBP_DEC_ALPHAI_DEC_H_

media/libwebp/dec/frame_dec.c

@@ -338,7 +338,6 @@ void VP8InitDithering(const WebPDecoderOptions* const options,
       for (s = 0; s < NUM_MB_SEGMENTS; ++s) {
         VP8QuantMatrix* const dqm = &dec->dqm_[s];
         if (dqm->uv_quant_ < DITHER_AMP_TAB_SIZE) {
-          // TODO(skal): should we specially dither more for uv_quant_ < 0?
           const int idx = (dqm->uv_quant_ < 0) ? 0 : dqm->uv_quant_;
           dqm->dither_ = (f * kQuantToDitherAmp[idx]) >> 3;
         }
@@ -669,15 +668,9 @@ int VP8GetThreadMethod(const WebPDecoderOptions* const options,
   (void)height;
   assert(headers == NULL || !headers->is_lossless);
 #if defined(WEBP_USE_THREAD)
-  if (width < MIN_WIDTH_FOR_THREADS) return 0;
+  if (width >= MIN_WIDTH_FOR_THREADS) return 2;
-  // TODO(skal): tune the heuristic further
-#if 0
-  if (height < 2 * width) return 2;
 #endif
-  return 2;
-#else   // !WEBP_USE_THREAD
   return 0;
-#endif
 }
 
 #undef MT_CACHE_LINES

media/libwebp/dec/idec_dec.c

@@ -140,10 +140,9 @@ static void DoRemap(WebPIDecoder* const idec, ptrdiff_t offset) {
       if (NeedCompressedAlpha(idec)) {
         ALPHDecoder* const alph_dec = dec->alph_dec_;
         dec->alpha_data_ += offset;
-        if (alph_dec != NULL) {
+        if (alph_dec != NULL && alph_dec->vp8l_dec_ != NULL) {
           if (alph_dec->method_ == ALPHA_LOSSLESS_COMPRESSION) {
             VP8LDecoder* const alph_vp8l_dec = alph_dec->vp8l_dec_;
-            assert(alph_vp8l_dec != NULL);
             assert(dec->alpha_data_size_ >= ALPHA_HEADER_LEN);
             VP8LBitReaderSetBuffer(&alph_vp8l_dec->br_,
                                    dec->alpha_data_ + ALPHA_HEADER_LEN,
@@ -449,7 +448,10 @@ static VP8StatusCode DecodeRemaining(WebPIDecoder* const idec) {
   VP8Decoder* const dec = (VP8Decoder*)idec->dec_;
   VP8Io* const io = &idec->io_;
 
-  assert(dec->ready_);
+  // Make sure partition #0 has been read before, to set dec to ready_.
+  if (!dec->ready_) {
+    return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
+  }
   for (; dec->mb_y_ < dec->mb_h_; ++dec->mb_y_) {
     if (idec->last_mb_y_ != dec->mb_y_) {
       if (!VP8ParseIntraModeRow(&dec->br_, dec)) {
@@ -471,6 +473,12 @@ static VP8StatusCode DecodeRemaining(WebPIDecoder* const idec) {
             MemDataSize(&idec->mem_) > MAX_MB_SIZE) {
           return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
         }
+        // Synchronize the threads.
+        if (dec->mt_method_ > 0) {
+          if (!WebPGetWorkerInterface()->Sync(&dec->worker_)) {
+            return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
+          }
+        }
         RestoreContext(&context, dec, token_br);
         return VP8_STATUS_SUSPENDED;
       }
@@ -489,6 +497,7 @@ static VP8StatusCode DecodeRemaining(WebPIDecoder* const idec) {
   }
   // Synchronize the thread and check for errors.
   if (!VP8ExitCritical(dec, io)) {
+    idec->state_ = STATE_ERROR;  // prevent re-entry in IDecError
     return IDecError(idec, VP8_STATUS_USER_ABORT);
   }
   dec->ready_ = 0;
@@ -569,6 +578,10 @@ static VP8StatusCode IDecode(WebPIDecoder* idec) {
     status = DecodePartition0(idec);
   }
   if (idec->state_ == STATE_VP8_DATA) {
+    const VP8Decoder* const dec = (VP8Decoder*)idec->dec_;
+    if (dec == NULL) {
+      return VP8_STATUS_SUSPENDED;  // can't continue if we have no decoder.
+    }
     status = DecodeRemaining(idec);
   }
   if (idec->state_ == STATE_VP8L_HEADER) {

media/libwebp/dec/vp8_dec.h

@@ -182,4 +182,4 @@ WEBP_EXTERN int VP8LGetInfo(
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_DEC_VP8_DEC_H_ */
+#endif  // WEBP_DEC_VP8_DEC_H_

media/libwebp/dec/vp8i_dec.h

@@ -32,7 +32,7 @@ extern "C" {
 // version numbers
 #define DEC_MAJ_VERSION 1
 #define DEC_MIN_VERSION 0
-#define DEC_REV_VERSION 0
+#define DEC_REV_VERSION 2
 
 // YUV-cache parameters. Cache is 32-bytes wide (= one cacheline).
 // Constraints are: We need to store one 16x16 block of luma samples (y),
@@ -316,4 +316,4 @@ const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec,
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_DEC_VP8I_DEC_H_ */
+#endif  // WEBP_DEC_VP8I_DEC_H_

media/libwebp/dec/vp8l_dec.c

@@ -359,17 +359,22 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
                             int color_cache_bits, int allow_recursion) {
   int i, j;
   VP8LBitReader* const br = &dec->br_;
-  VP8LBitReader br_tmp;
   VP8LMetadata* const hdr = &dec->hdr_;
   uint32_t* huffman_image = NULL;
   HTreeGroup* htree_groups = NULL;
+  // When reading htrees, some might be unused, as the format allows it.
+  // We will still read them but put them in this htree_group_bogus.
+  HTreeGroup htree_group_bogus;
   HuffmanCode* huffman_tables = NULL;
+  HuffmanCode* huffman_tables_bogus = NULL;
   HuffmanCode* next = NULL;
   int num_htree_groups = 1;
-  int num_htree_groups_limit = 1;
+  int num_htree_groups_max = 1;
   int max_alphabet_size = 0;
   int* code_lengths = NULL;
   const int table_size = kTableSize[color_cache_bits];
+  int* mapping = NULL;
+  int ok = 0;
 
   if (allow_recursion && VP8LReadBits(br, 1)) {
     // use meta Huffman codes.
@@ -386,21 +391,41 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
       // The huffman data is stored in red and green bytes.
       const int group = (huffman_image[i] >> 8) & 0xffff;
       huffman_image[i] = group;
-      if (group >= num_htree_groups) {
+      if (group >= num_htree_groups_max) {
-        num_htree_groups = group + 1;
+        num_htree_groups_max = group + 1;
       }
     }
-    // Check the validity of num_htree_groups. If it seems too big, use a
+    // Check the validity of num_htree_groups_max. If it seems too big, use a
     // smaller value for later. This will prevent big memory allocations to end
     // up with a bad bitstream anyway.
-    // The value of 1000 is totally arbitrary. We know that num_htree_groups
+    // The value of 1000 is totally arbitrary. We know that num_htree_groups_max
     // is smaller than (1 << 16) and should be smaller than the number of pixels
     // (though the format allows it to be bigger).
-    if (num_htree_groups > 1000 || num_htree_groups > xsize * ysize) {
+    if (num_htree_groups_max > 1000 || num_htree_groups_max > xsize * ysize) {
-      num_htree_groups_limit = (xsize * ysize > 1000) ? 1000 : xsize * ysize;
+      // Create a mapping from the used indices to the minimal set of used
-      br_tmp = dec->br_;
+      // values [0, num_htree_groups)
+      mapping = (int*)WebPSafeMalloc(num_htree_groups_max, sizeof(*mapping));
+      if (mapping == NULL) {
+        dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
+        goto Error;
+      }
+      // -1 means a value is unmapped, and therefore unused in the Huffman
+      // image.
+      memset(mapping, 0xff, num_htree_groups_max * sizeof(*mapping));
+      for (num_htree_groups = 0, i = 0; i < huffman_pixs; ++i) {
+        // Get the current mapping for the group and remap the Huffman image.
+        int* const mapped_group = &mapping[huffman_image[i]];
+        if (*mapped_group == -1) *mapped_group = num_htree_groups++;
+        huffman_image[i] = *mapped_group;
+      }
+      huffman_tables_bogus = (HuffmanCode*)WebPSafeMalloc(
+          table_size, sizeof(*huffman_tables_bogus));
+      if (huffman_tables_bogus == NULL) {
+        dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
+        goto Error;
+      }
     } else {
-      num_htree_groups_limit = num_htree_groups;
+      num_htree_groups = num_htree_groups_max;
     }
   }
 
@@ -419,46 +444,45 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
 
   code_lengths = (int*)WebPSafeCalloc((uint64_t)max_alphabet_size,
                                       sizeof(*code_lengths));
-  // If num_htree_groups_tmp == num_htree_groups, the following loop is executed
+  huffman_tables = (HuffmanCode*)WebPSafeMalloc(num_htree_groups * table_size,
-  // once.
+                                                sizeof(*huffman_tables));
-  // If num_htree_groups_tmp != num_htree_groups, we execute the loop the first
+  htree_groups = VP8LHtreeGroupsNew(num_htree_groups);
-  // time with little memory allocation in the hope that there is a bitstream
-  // error. If after num_htree_groups_tmp iterations, no error appears,
-  // num_htree_groups is probably the right value so try it out.
-  do {
-    huffman_tables = (HuffmanCode*)WebPSafeMalloc(
-        num_htree_groups_limit * table_size, sizeof(*huffman_tables));
-    htree_groups = VP8LHtreeGroupsNew(num_htree_groups_limit);
 
-    if (htree_groups == NULL || code_lengths == NULL ||
+  if (htree_groups == NULL || code_lengths == NULL || huffman_tables == NULL) {
-        huffman_tables == NULL) {
     dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
     goto Error;
   }
 
   next = huffman_tables;
-    for (i = 0; i < num_htree_groups_limit; ++i) {
+  for (i = 0; i < num_htree_groups_max; ++i) {
-      HTreeGroup* const htree_group = &htree_groups[i];
+    // If the index "i" is unused in the Huffman image, read the coefficients
+    // but store them to a bogus htree_group.
+    const int is_bogus = (mapping != NULL && mapping[i] == -1);
+    HTreeGroup* const htree_group =
+        is_bogus ? &htree_group_bogus :
+        &htree_groups[(mapping == NULL) ? i : mapping[i]];
     HuffmanCode** const htrees = htree_group->htrees;
+    HuffmanCode* huffman_tables_i = is_bogus ? huffman_tables_bogus : next;
     int size;
     int total_size = 0;
     int is_trivial_literal = 1;
     int max_bits = 0;
     for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
       int alphabet_size = kAlphabetSize[j];
-        htrees[j] = next;
+      htrees[j] = huffman_tables_i;
       if (j == 0 && color_cache_bits > 0) {
         alphabet_size += 1 << color_cache_bits;
       }
-        size = ReadHuffmanCode(alphabet_size, dec, code_lengths, next);
+      size =
+          ReadHuffmanCode(alphabet_size, dec, code_lengths, huffman_tables_i);
       if (size == 0) {
         goto Error;
       }
       if (is_trivial_literal && kLiteralMap[j] == 1) {
-          is_trivial_literal = (next->bits == 0);
+        is_trivial_literal = (huffman_tables_i->bits == 0);
       }
-        total_size += next->bits;
+      total_size += huffman_tables_i->bits;
-        next += size;
+      huffman_tables_i += size;
       if (j <= ALPHA) {
         int local_max_bits = code_lengths[0];
         int k;
@@ -470,6 +494,7 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
         max_bits += local_max_bits;
       }
     }
+    if (!is_bogus) next = huffman_tables_i;
     htree_group->is_trivial_literal = is_trivial_literal;
     htree_group->is_trivial_code = 0;
     if (is_trivial_literal) {
@@ -486,32 +511,24 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
         !htree_group->is_trivial_code && (max_bits < HUFFMAN_PACKED_BITS);
     if (htree_group->use_packed_table) BuildPackedTable(htree_group);
   }
-    // If we have survived up to here, num_htree_groups might actually be
+  ok = 1;
-    // that big so restart with a proper allocation.
-    if (num_htree_groups != num_htree_groups_limit) {
-      num_htree_groups_limit = num_htree_groups;
-      WebPSafeFree(huffman_tables);
-      VP8LHtreeGroupsFree(htree_groups);
-      huffman_tables = NULL;
-      htree_groups = NULL;
-      dec->br_ = br_tmp;
-    }
-  } while (i != num_htree_groups);
-  WebPSafeFree(code_lengths);
 
-  // All OK. Finalize pointers and return.
+  // All OK. Finalize pointers.
   hdr->huffman_image_ = huffman_image;
   hdr->num_htree_groups_ = num_htree_groups;
   hdr->htree_groups_ = htree_groups;
   hdr->huffman_tables_ = huffman_tables;
-  return 1;
 
  Error:
   WebPSafeFree(code_lengths);
+  WebPSafeFree(huffman_tables_bogus);
+  WebPSafeFree(mapping);
+  if (!ok) {
     WebPSafeFree(huffman_image);
     WebPSafeFree(huffman_tables);
     VP8LHtreeGroupsFree(htree_groups);
-  return 0;
+  }
+  return ok;
 }
 
 //------------------------------------------------------------------------------
@@ -916,7 +933,11 @@ static WEBP_INLINE void CopyBlock8b(uint8_t* const dst, int dist, int length) {
 #endif
         break;
       case 2:
+#if !defined(WORDS_BIGENDIAN)
         memcpy(&pattern, src, sizeof(uint16_t));
+#else
+        pattern = ((uint32_t)src[0] << 8) | src[1];
+#endif
 #if defined(__arm__) || defined(_M_ARM)
         pattern |= pattern << 16;
 #elif defined(WEBP_USE_MIPS_DSP_R2)
@@ -1555,7 +1576,6 @@ int VP8LDecodeAlphaHeader(ALPHDecoder* const alph_dec,
   if (dec == NULL) return 0;
 
   assert(alph_dec != NULL);
-  alph_dec->vp8l_dec_ = dec;
 
   dec->width_ = alph_dec->width_;
   dec->height_ = alph_dec->height_;
@@ -1587,11 +1607,12 @@ int VP8LDecodeAlphaHeader(ALPHDecoder* const alph_dec,
 
   if (!ok) goto Err;
 
+  // Only set here, once we are sure it is valid (to avoid thread races).
+  alph_dec->vp8l_dec_ = dec;
   return 1;
 
  Err:
-  VP8LDelete(alph_dec->vp8l_dec_);
+  VP8LDelete(dec);
-  alph_dec->vp8l_dec_ = NULL;
   return 0;
 }
 

media/libwebp/dec/vp8li_dec.h

@@ -132,4 +132,4 @@ void VP8LDelete(VP8LDecoder* const dec);
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_DEC_VP8LI_DEC_H_ */
+#endif  // WEBP_DEC_VP8LI_DEC_H_

media/libwebp/dec/webpi_dec.h

@@ -130,4 +130,4 @@ int WebPAvoidSlowMemory(const WebPDecBuffer* const output,
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_DEC_WEBPI_DEC_H_ */
+#endif  // WEBP_DEC_WEBPI_DEC_H_

media/libwebp/demux/demux.c

@@ -25,7 +25,7 @@
 
 #define DMUX_MAJ_VERSION 1
 #define DMUX_MIN_VERSION 0
-#define DMUX_REV_VERSION 0
+#define DMUX_REV_VERSION 2
 
 typedef struct {
   size_t start_;        // start location of the data

media/libwebp/dsp/dsp.h

@@ -76,10 +76,6 @@ extern "C" {
 #define WEBP_USE_SSE41
 #endif
 
-#if defined(__AVX2__) || defined(WEBP_HAVE_AVX2)
-#define WEBP_USE_AVX2
-#endif
-
 // The intrinsics currently cause compiler errors with arm-nacl-gcc and the
 // inline assembly would need to be modified for use with Native Client.
 #if (defined(__ARM_NEON__) || \
@@ -679,4 +675,4 @@ void VP8FiltersInit(void);
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_DSP_DSP_H_ */
+#endif  // WEBP_DSP_DSP_H_

media/libwebp/dsp/lossless.c

@@ -23,8 +23,6 @@
 #include "../dsp/lossless.h"
 #include "../dsp/lossless_common.h"
 
-#define MAX_DIFF_COST (1e30f)
-
 //------------------------------------------------------------------------------
 // Image transforms.
 

media/libwebp/dsp/lossless.h

@@ -163,7 +163,7 @@ extern VP8LCostCombinedFunc VP8LExtraCostCombined;
 extern VP8LCombinedShannonEntropyFunc VP8LCombinedShannonEntropy;
 
 typedef struct {        // small struct to hold counters
-  int counts[2];        // index: 0=zero steak, 1=non-zero streak
+  int counts[2];        // index: 0=zero streak, 1=non-zero streak
   int streaks[2][2];    // [zero/non-zero][streak<3 / streak>=3]
 } VP8LStreaks;
 
@@ -194,10 +194,14 @@ extern VP8LGetEntropyUnrefinedFunc VP8LGetEntropyUnrefined;
 void VP8LBitsEntropyUnrefined(const uint32_t* const array, int n,
                               VP8LBitEntropy* const entropy);
 
-typedef void (*VP8LHistogramAddFunc)(const VP8LHistogram* const a,
+typedef void (*VP8LAddVectorFunc)(const uint32_t* a, const uint32_t* b,
+                                  uint32_t* out, int size);
+extern VP8LAddVectorFunc VP8LAddVector;
+typedef void (*VP8LAddVectorEqFunc)(const uint32_t* a, uint32_t* out, int size);
+extern VP8LAddVectorEqFunc VP8LAddVectorEq;
+void VP8LHistogramAdd(const VP8LHistogram* const a,
                       const VP8LHistogram* const b,
                       VP8LHistogram* const out);
-extern VP8LHistogramAddFunc VP8LHistogramAdd;
 
 // -----------------------------------------------------------------------------
 // PrefixEncode()

media/libwebp/dsp/msa_macro.h

@@ -1389,4 +1389,4 @@ static WEBP_INLINE uint32_t func_hadd_uh_u32(v8u16 in) {
 } while (0)
 #define AVER_UB2_UB(...) AVER_UB2(v16u8, __VA_ARGS__)
 
-#endif  /* WEBP_DSP_MSA_MACRO_H_ */
+#endif  // WEBP_DSP_MSA_MACRO_H_

media/libwebp/dsp/quant.h

@@ -0,0 +1,70 @@
+// Copyright 2018 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+
+#ifndef WEBP_DSP_QUANT_H_
+#define WEBP_DSP_QUANT_H_
+
+#include "../dsp/dsp.h"
+#include "../webp/types.h"
+
+#if defined(WEBP_USE_NEON) && !defined(WEBP_ANDROID_NEON) && \
+    !defined(WEBP_HAVE_NEON_RTCD)
+#include <arm_neon.h>
+
+#define IsFlat IsFlat_NEON
+
+static uint32x2_t horizontal_add_uint32x4(const uint32x4_t a) {
+  const uint64x2_t b = vpaddlq_u32(a);
+  return vadd_u32(vreinterpret_u32_u64(vget_low_u64(b)),
+                  vreinterpret_u32_u64(vget_high_u64(b)));
+}
+
+static WEBP_INLINE int IsFlat(const int16_t* levels, int num_blocks,
+                              int thresh) {
+  const int16x8_t tst_ones = vdupq_n_s16(-1);
+  uint32x4_t sum = vdupq_n_u32(0);
+
+  for (int i = 0; i < num_blocks; ++i) {
+    // Set DC to zero.
+    const int16x8_t a_0 = vsetq_lane_s16(0, vld1q_s16(levels), 0);
+    const int16x8_t a_1 = vld1q_s16(levels + 8);
+
+    const uint16x8_t b_0 = vshrq_n_u16(vtstq_s16(a_0, tst_ones), 15);
+    const uint16x8_t b_1 = vshrq_n_u16(vtstq_s16(a_1, tst_ones), 15);
+
+    sum = vpadalq_u16(sum, b_0);
+    sum = vpadalq_u16(sum, b_1);
+
+    levels += 16;
+  }
+  return thresh >= (int32_t)vget_lane_u32(horizontal_add_uint32x4(sum), 0);
+}
+
+#else
+
+#define IsFlat IsFlat_C
+
+static WEBP_INLINE int IsFlat(const int16_t* levels, int num_blocks,
+                              int thresh) {
+  int score = 0;
+  while (num_blocks-- > 0) {      // TODO(skal): refine positional scoring?
+    int i;
+    for (i = 1; i < 16; ++i) {    // omit DC, we're only interested in AC
+      score += (levels[i] != 0);
+      if (score > thresh) return 0;
+    }
+    levels += 16;
+  }
+  return 1;
+}
+
+#endif  // defined(WEBP_USE_NEON) && !defined(WEBP_ANDROID_NEON) &&
+        // !defined(WEBP_HAVE_NEON_RTCD)
+
+#endif  // WEBP_DSP_QUANT_H_

media/libwebp/dsp/rescaler.c

@@ -21,6 +21,7 @@
 
 #define ROUNDER (WEBP_RESCALER_ONE >> 1)
 #define MULT_FIX(x, y) (((uint64_t)(x) * (y) + ROUNDER) >> WEBP_RESCALER_RFIX)
+#define MULT_FIX_FLOOR(x, y) (((uint64_t)(x) * (y)) >> WEBP_RESCALER_RFIX)
 
 //------------------------------------------------------------------------------
 // Row import
@@ -138,7 +139,7 @@ void WebPRescalerExportRowShrink_C(WebPRescaler* const wrk) {
   if (yscale) {
     for (x_out = 0; x_out < x_out_max; ++x_out) {
       const uint32_t frac = (uint32_t)MULT_FIX(frow[x_out], yscale);
-      const int v = (int)MULT_FIX(irow[x_out] - frac, wrk->fxy_scale);
+      const int v = (int)MULT_FIX_FLOOR(irow[x_out] - frac, wrk->fxy_scale);
       assert(v >= 0 && v <= 255);
       dst[x_out] = v;
       irow[x_out] = frac;   // new fractional start
@@ -153,6 +154,7 @@ void WebPRescalerExportRowShrink_C(WebPRescaler* const wrk) {
   }
 }
 
+#undef MULT_FIX_FLOOR
 #undef MULT_FIX
 #undef ROUNDER
 

media/libwebp/dsp/rescaler_neon.c

@@ -22,6 +22,7 @@
 
 #define ROUNDER (WEBP_RESCALER_ONE >> 1)
 #define MULT_FIX_C(x, y) (((uint64_t)(x) * (y) + ROUNDER) >> WEBP_RESCALER_RFIX)
+#define MULT_FIX_FLOOR_C(x, y) (((uint64_t)(x) * (y)) >> WEBP_RESCALER_RFIX)
 
 #define LOAD_32x4(SRC, DST) const uint32x4_t DST = vld1q_u32((SRC))
 #define LOAD_32x8(SRC, DST0, DST1)                                    \
@@ -35,8 +36,11 @@
 
 #if (WEBP_RESCALER_RFIX == 32)
 #define MAKE_HALF_CST(C) vdupq_n_s32((int32_t)((C) >> 1))
-#define MULT_FIX(A, B) /* note: B is actualy scale>>1. See MAKE_HALF_CST */ \
+// note: B is actualy scale>>1. See MAKE_HALF_CST
+#define MULT_FIX(A, B) \
     vreinterpretq_u32_s32(vqrdmulhq_s32(vreinterpretq_s32_u32((A)), (B)))
+#define MULT_FIX_FLOOR(A, B) \
+    vreinterpretq_u32_s32(vqdmulhq_s32(vreinterpretq_s32_u32((A)), (B)))
 #else
 #error "MULT_FIX/WEBP_RESCALER_RFIX need some more work"
 #endif
@@ -135,8 +139,8 @@ static void RescalerExportRowShrink_NEON(WebPRescaler* const wrk) {
       const uint32x4_t A1 = MULT_FIX(in1, yscale_half);
       const uint32x4_t B0 = vqsubq_u32(in2, A0);
       const uint32x4_t B1 = vqsubq_u32(in3, A1);
-      const uint32x4_t C0 = MULT_FIX(B0, fxy_scale_half);
+      const uint32x4_t C0 = MULT_FIX_FLOOR(B0, fxy_scale_half);
-      const uint32x4_t C1 = MULT_FIX(B1, fxy_scale_half);
+      const uint32x4_t C1 = MULT_FIX_FLOOR(B1, fxy_scale_half);
       const uint16x4_t D0 = vmovn_u32(C0);
       const uint16x4_t D1 = vmovn_u32(C1);
       const uint8x8_t E = vmovn_u16(vcombine_u16(D0, D1));
@@ -145,7 +149,7 @@ static void RescalerExportRowShrink_NEON(WebPRescaler* const wrk) {
     }
     for (; x_out < x_out_max; ++x_out) {
       const uint32_t frac = (uint32_t)MULT_FIX_C(frow[x_out], yscale);
-      const int v = (int)MULT_FIX_C(irow[x_out] - frac, wrk->fxy_scale);
+      const int v = (int)MULT_FIX_FLOOR_C(irow[x_out] - frac, fxy_scale);
       assert(v >= 0 && v <= 255);
       dst[x_out] = v;
       irow[x_out] = frac;   // new fractional start
@@ -170,6 +174,12 @@ static void RescalerExportRowShrink_NEON(WebPRescaler* const wrk) {
   }
 }
 
+#undef MULT_FIX_FLOOR_C
+#undef MULT_FIX_C
+#undef MULT_FIX_FLOOR
+#undef MULT_FIX
+#undef ROUNDER
+
 //------------------------------------------------------------------------------
 
 extern void WebPRescalerDspInitNEON(void);

media/libwebp/dsp/rescaler_sse2.c

@@ -25,6 +25,7 @@
 
 #define ROUNDER (WEBP_RESCALER_ONE >> 1)
 #define MULT_FIX(x, y) (((uint64_t)(x) * (y) + ROUNDER) >> WEBP_RESCALER_RFIX)
+#define MULT_FIX_FLOOR(x, y) (((uint64_t)(x) * (y)) >> WEBP_RESCALER_RFIX)
 
 // input: 8 bytes ABCDEFGH -> output: A0E0B0F0C0G0D0H0
 static void LoadTwoPixels_SSE2(const uint8_t* const src, __m128i* out) {
@@ -224,6 +225,35 @@ static WEBP_INLINE void ProcessRow_SSE2(const __m128i* const A0,
   _mm_storel_epi64((__m128i*)dst, G);
 }
 
+static WEBP_INLINE void ProcessRow_Floor_SSE2(const __m128i* const A0,
+                                              const __m128i* const A1,
+                                              const __m128i* const A2,
+                                              const __m128i* const A3,
+                                              const __m128i* const mult,
+                                              uint8_t* const dst) {
+  const __m128i mask = _mm_set_epi32(0xffffffffu, 0, 0xffffffffu, 0);
+  const __m128i B0 = _mm_mul_epu32(*A0, *mult);
+  const __m128i B1 = _mm_mul_epu32(*A1, *mult);
+  const __m128i B2 = _mm_mul_epu32(*A2, *mult);
+  const __m128i B3 = _mm_mul_epu32(*A3, *mult);
+  const __m128i D0 = _mm_srli_epi64(B0, WEBP_RESCALER_RFIX);
+  const __m128i D1 = _mm_srli_epi64(B1, WEBP_RESCALER_RFIX);
+#if (WEBP_RESCALER_RFIX < 32)
+  const __m128i D2 =
+      _mm_and_si128(_mm_slli_epi64(B2, 32 - WEBP_RESCALER_RFIX), mask);
+  const __m128i D3 =
+      _mm_and_si128(_mm_slli_epi64(B3, 32 - WEBP_RESCALER_RFIX), mask);
+#else
+  const __m128i D2 = _mm_and_si128(B2, mask);
+  const __m128i D3 = _mm_and_si128(B3, mask);
+#endif
+  const __m128i E0 = _mm_or_si128(D0, D2);
+  const __m128i E1 = _mm_or_si128(D1, D3);
+  const __m128i F = _mm_packs_epi32(E0, E1);
+  const __m128i G = _mm_packus_epi16(F, F);
+  _mm_storel_epi64((__m128i*)dst, G);
+}
+
 static void RescalerExportRowExpand_SSE2(WebPRescaler* const wrk) {
   int x_out;
   uint8_t* const dst = wrk->dst;
@@ -322,12 +352,12 @@ static void RescalerExportRowShrink_SSE2(WebPRescaler* const wrk) {
         const __m128i G1 = _mm_or_si128(D1, F3);
         _mm_storeu_si128((__m128i*)(irow + x_out + 0), G0);
         _mm_storeu_si128((__m128i*)(irow + x_out + 4), G1);
-        ProcessRow_SSE2(&E0, &E1, &E2, &E3, &mult_xy, dst + x_out);
+        ProcessRow_Floor_SSE2(&E0, &E1, &E2, &E3, &mult_xy, dst + x_out);
       }
     }
     for (; x_out < x_out_max; ++x_out) {
       const uint32_t frac = (int)MULT_FIX(frow[x_out], yscale);
-      const int v = (int)MULT_FIX(irow[x_out] - frac, wrk->fxy_scale);
+      const int v = (int)MULT_FIX_FLOOR(irow[x_out] - frac, wrk->fxy_scale);
       assert(v >= 0 && v <= 255);
       dst[x_out] = v;
       irow[x_out] = frac;   // new fractional start
@@ -352,6 +382,7 @@ static void RescalerExportRowShrink_SSE2(WebPRescaler* const wrk) {
   }
 }
 
+#undef MULT_FIX_FLOOR
 #undef MULT_FIX
 #undef ROUNDER
 

media/libwebp/dsp/yuv.h

@@ -207,4 +207,4 @@ static WEBP_INLINE int VP8RGBToV(int r, int g, int b, int rounding) {
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_DSP_YUV_H_ */
+#endif  // WEBP_DSP_YUV_H_

media/libwebp/enc/cost_enc.h

@@ -79,4 +79,4 @@ extern const uint16_t VP8FixedCostsI4[NUM_BMODES][NUM_BMODES][NUM_BMODES];
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_ENC_COST_ENC_H_ */
+#endif  // WEBP_ENC_COST_ENC_H_

media/libwebp/enc/histogram_enc.h

@@ -44,6 +44,7 @@ typedef struct {
   double literal_cost_;      // Cached values of dominant entropy costs:
   double red_cost_;          // literal, red & blue.
   double blue_cost_;
+  uint8_t is_used_[5];       // 5 for literal, red, blue, alpha, distance
 } VP8LHistogram;
 
 // Collection of histograms with fixed capacity, allocated as one
@@ -67,7 +68,9 @@ void VP8LHistogramCreate(VP8LHistogram* const p,
 int VP8LGetHistogramSize(int palette_code_bits);
 
 // Set the palette_code_bits and reset the stats.
-void VP8LHistogramInit(VP8LHistogram* const p, int palette_code_bits);
+// If init_arrays is true, the arrays are also filled with 0's.
+void VP8LHistogramInit(VP8LHistogram* const p, int palette_code_bits,
+                       int init_arrays);
 
 // Collect all the references into a histogram (without reset)
 void VP8LHistogramStoreRefs(const VP8LBackwardRefs* const refs,
@@ -83,6 +86,9 @@ void VP8LFreeHistogramSet(VP8LHistogramSet* const histo);
 // using 'cache_bits'. Return NULL in case of memory error.
 VP8LHistogramSet* VP8LAllocateHistogramSet(int size, int cache_bits);
 
+// Set the histograms in set to 0.
+void VP8LHistogramSetClear(VP8LHistogramSet* const set);
+
 // Allocate and initialize histogram object with specified 'cache_bits'.
 // Returns NULL in case of memory error.
 // Special case of VP8LAllocateHistogramSet, with size equals 1.
@@ -113,7 +119,7 @@ double VP8LBitsEntropy(const uint32_t* const array, int n);
 
 // Estimate how many bits the combined entropy of literals and distance
 // approximately maps to.
-double VP8LHistogramEstimateBits(const VP8LHistogram* const p);
+double VP8LHistogramEstimateBits(VP8LHistogram* const p);
 
 #ifdef __cplusplus
 }

media/libwebp/enc/vp8i_enc.h

@@ -32,7 +32,7 @@ extern "C" {
 // version numbers
 #define ENC_MAJ_VERSION 1
 #define ENC_MIN_VERSION 0
-#define ENC_REV_VERSION 0
+#define ENC_REV_VERSION 2
 
 enum { MAX_LF_LEVELS = 64,       // Maximum loop filter level
        MAX_VARIABLE_LEVEL = 67,  // last (inclusive) level with variable cost
@@ -278,7 +278,7 @@ int VP8IteratorIsDone(const VP8EncIterator* const it);
 // Import uncompressed samples from source.
 // If tmp_32 is not NULL, import boundary samples too.
 // tmp_32 is a 32-bytes scratch buffer that must be aligned in memory.
-void VP8IteratorImport(VP8EncIterator* const it, uint8_t* tmp_32);
+void VP8IteratorImport(VP8EncIterator* const it, uint8_t* const tmp_32);
 // export decimated samples
 void VP8IteratorExport(const VP8EncIterator* const it);
 // go to next macroblock. Returns false if not finished.
@@ -515,4 +515,4 @@ void WebPCleanupTransparentAreaLossless(WebPPicture* const pic);
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_ENC_VP8I_ENC_H_ */
+#endif  // WEBP_ENC_VP8I_ENC_H_

media/libwebp/enc/vp8li_enc.h

@@ -115,4 +115,4 @@ void VP8LColorSpaceTransform(int width, int height, int bits, int quality,
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_ENC_VP8LI_ENC_H_ */
+#endif  // WEBP_ENC_VP8LI_ENC_H_

media/libwebp/utils/bit_reader_utils.h

@@ -172,4 +172,4 @@ static WEBP_INLINE void VP8LFillBitWindow(VP8LBitReader* const br) {
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_UTILS_BIT_READER_UTILS_H_ */
+#endif  // WEBP_UTILS_BIT_READER_UTILS_H_

media/libwebp/utils/bit_writer_utils.h

@@ -151,4 +151,4 @@ static WEBP_INLINE void VP8LPutBits(VP8LBitWriter* const bw,
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_UTILS_BIT_WRITER_UTILS_H_ */
+#endif  // WEBP_UTILS_BIT_WRITER_UTILS_H_

media/libwebp/utils/filters_utils.h

@@ -29,4 +29,4 @@ WEBP_FILTER_TYPE WebPEstimateBestFilter(const uint8_t* data,
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_UTILS_FILTERS_UTILS_H_ */
+#endif  // WEBP_UTILS_FILTERS_UTILS_H_

media/libwebp/utils/quant_levels_dec_utils.c

@@ -261,9 +261,15 @@ static void CleanupParams(SmoothParams* const p) {
 
 int WebPDequantizeLevels(uint8_t* const data, int width, int height, int stride,
                          int strength) {
-  const int radius = 4 * strength / 100;
+  int radius = 4 * strength / 100;
+
   if (strength < 0 || strength > 100) return 0;
   if (data == NULL || width <= 0 || height <= 0) return 0;  // bad params
+
+  // limit the filter size to not exceed the image dimensions
+  if (2 * radius + 1 > width) radius = (width - 1) >> 1;
+  if (2 * radius + 1 > height) radius = (height - 1) >> 1;
+
   if (radius > 0) {
     SmoothParams p;
     memset(&p, 0, sizeof(p));

media/libwebp/utils/quant_levels_dec_utils.h

@@ -32,4 +32,4 @@ int WebPDequantizeLevels(uint8_t* const data, int width, int height, int stride,
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_UTILS_QUANT_LEVELS_DEC_UTILS_H_ */
+#endif  // WEBP_UTILS_QUANT_LEVELS_DEC_UTILS_H_

media/libwebp/utils/quant_levels_utils.h

@@ -33,4 +33,4 @@ int QuantizeLevels(uint8_t* const data, int width, int height, int num_levels,
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_UTILS_QUANT_LEVELS_UTILS_H_ */
+#endif  // WEBP_UTILS_QUANT_LEVELS_UTILS_H_

media/libwebp/utils/random_utils.h

@@ -60,4 +60,4 @@ static WEBP_INLINE int VP8RandomBits(VP8Random* const rg, int num_bits) {
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_UTILS_RANDOM_UTILS_H_ */
+#endif  // WEBP_UTILS_RANDOM_UTILS_H_

media/libwebp/utils/rescaler_utils.h

@@ -98,4 +98,4 @@ int WebPRescalerHasPendingOutput(const WebPRescaler* const rescaler) {
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_UTILS_RESCALER_UTILS_H_ */
+#endif  // WEBP_UTILS_RESCALER_UTILS_H_

media/libwebp/utils/thread_utils.h

@@ -87,4 +87,4 @@ WEBP_EXTERN const WebPWorkerInterface* WebPGetWorkerInterface(void);
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_UTILS_THREAD_UTILS_H_ */
+#endif  // WEBP_UTILS_THREAD_UTILS_H_

media/libwebp/utils/utils.h

@@ -107,19 +107,6 @@ static WEBP_INLINE void PutLE32(uint8_t* const data, uint32_t val) {
   PutLE16(data + 2, (int)(val >> 16));
 }
 
-// Returns 31 ^ clz(n) = log2(n). This is the default C-implementation, either
-// based on table or not. Can be used as fallback if clz() is not available.
-#define WEBP_NEED_LOG_TABLE_8BIT
-extern const uint8_t WebPLogTable8bit[256];
-static WEBP_INLINE int WebPLog2FloorC(uint32_t n) {
-  int log_value = 0;
-  while (n >= 256) {
-    log_value += 8;
-    n >>= 8;
-  }
-  return log_value + WebPLogTable8bit[n];
-}
-
 // Returns (int)floor(log2(n)). n must be > 0.
 // use GNU builtins where available.
 #if defined(__GNUC__) && \
@@ -138,6 +125,19 @@ static WEBP_INLINE int BitsLog2Floor(uint32_t n) {
   return first_set_bit;
 }
 #else   // default: use the C-version.
+// Returns 31 ^ clz(n) = log2(n). This is the default C-implementation, either
+// based on table or not. Can be used as fallback if clz() is not available.
+#define WEBP_NEED_LOG_TABLE_8BIT
+extern const uint8_t WebPLogTable8bit[256];
+static WEBP_INLINE int WebPLog2FloorC(uint32_t n) {
+  int log_value = 0;
+  while (n >= 256) {
+    log_value += 8;
+    n >>= 8;
+  }
+  return log_value + WebPLogTable8bit[n];
+}
+
 static WEBP_INLINE int BitsLog2Floor(uint32_t n) { return WebPLog2FloorC(n); }
 #endif
 
@@ -175,4 +175,4 @@ WEBP_EXTERN int WebPGetColorPalette(const struct WebPPicture* const pic,
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_UTILS_UTILS_H_ */
+#endif  // WEBP_UTILS_UTILS_H_

media/libwebp/webp/decode.h

@@ -42,6 +42,12 @@ WEBP_EXTERN int WebPGetDecoderVersion(void);
 // This function will also validate the header, returning true on success,
 // false otherwise. '*width' and '*height' are only valid on successful return.
 // Pointers 'width' and 'height' can be passed NULL if deemed irrelevant.
+// Note: The following chunk sequences (before the raw VP8/VP8L data) are
+// considered valid by this function:
+// RIFF + VP8(L)
+// RIFF + VP8X + (optional chunks) + VP8(L)
+// ALPH + VP8 <-- Not a valid WebP format: only allowed for internal purpose.
+// VP8(L)     <-- Not a valid WebP format: only allowed for internal purpose.
 WEBP_EXTERN int WebPGetInfo(const uint8_t* data, size_t data_size,
                             int* width, int* height);
 
@@ -425,6 +431,12 @@ WEBP_EXTERN VP8StatusCode WebPGetFeaturesInternal(
 // Returns VP8_STATUS_OK when the features are successfully retrieved. Returns
 // VP8_STATUS_NOT_ENOUGH_DATA when more data is needed to retrieve the
 // features from headers. Returns error in other cases.
+// Note: The following chunk sequences (before the raw VP8/VP8L data) are
+// considered valid by this function:
+// RIFF + VP8(L)
+// RIFF + VP8X + (optional chunks) + VP8(L)
+// ALPH + VP8 <-- Not a valid WebP format: only allowed for internal purpose.
+// VP8(L)     <-- Not a valid WebP format: only allowed for internal purpose.
 static WEBP_INLINE VP8StatusCode WebPGetFeatures(
     const uint8_t* data, size_t data_size,
     WebPBitstreamFeatures* features) {
@@ -491,4 +503,4 @@ WEBP_EXTERN VP8StatusCode WebPDecode(const uint8_t* data, size_t data_size,
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_WEBP_DECODE_H_ */
+#endif  // WEBP_WEBP_DECODE_H_

media/libwebp/webp/demux.h

@@ -360,4 +360,4 @@ WEBP_EXTERN void WebPAnimDecoderDelete(WebPAnimDecoder* dec);
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_WEBP_DEMUX_H_ */
+#endif  // WEBP_WEBP_DEMUX_H_

media/libwebp/webp/encode.h

@@ -542,4 +542,4 @@ WEBP_EXTERN int WebPEncode(const WebPConfig* config, WebPPicture* picture);
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_WEBP_ENCODE_H_ */
+#endif  // WEBP_WEBP_ENCODE_H_

media/libwebp/webp/format_constants.h

@@ -84,4 +84,4 @@ typedef enum {
 // overflow a uint32_t.
 #define MAX_CHUNK_PAYLOAD (~0U - CHUNK_HEADER_SIZE - 1)
 
-#endif  /* WEBP_WEBP_FORMAT_CONSTANTS_H_ */
+#endif  // WEBP_WEBP_FORMAT_CONSTANTS_H_

media/libwebp/webp/mux.h

@@ -527,4 +527,4 @@ WEBP_EXTERN void WebPAnimEncoderDelete(WebPAnimEncoder* enc);
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_WEBP_MUX_H_ */
+#endif  // WEBP_WEBP_MUX_H_

media/libwebp/webp/mux_types.h

@@ -95,4 +95,4 @@ static WEBP_INLINE int WebPDataCopy(const WebPData* src, WebPData* dst) {
 }    // extern "C"
 #endif
 
-#endif  /* WEBP_WEBP_MUX_TYPES_H_ */
+#endif  // WEBP_WEBP_MUX_TYPES_H_

media/libwebp/webp/types.h

@@ -49,4 +49,4 @@ typedef long long int int64_t;
 // Macro to check ABI compatibility (same major revision number)
 #define WEBP_ABI_IS_INCOMPATIBLE(a, b) (((a) >> 8) != ((b) >> 8))
 
-#endif  /* WEBP_WEBP_TYPES_H_ */
+#endif  // WEBP_WEBP_TYPES_H_