Merge "reorganize chunk-parsing code"

src/dec/idec.c

@@ -20,9 +20,8 @@
 extern "C" {
 #endif
 
-#define RIFF_HEADER_SIZE 20
+#define RIFF_HEADER_SIZE 12
 #define VP8_HEADER_SIZE 10
-#define WEBP_HEADER_SIZE (RIFF_HEADER_SIZE + VP8_HEADER_SIZE)
 #define CHUNK_SIZE 4096
 #define MAX_MB_SIZE 4096
 
@@ -245,16 +244,40 @@ static VP8StatusCode DecodeHeader(WebPIDecoder* const idec) {
   const uint8_t* data = idec->mem_.buf_ + idec->mem_.start_;
   uint32_t curr_size = MemDataSize(&idec->mem_);
   uint32_t chunk_size;
+  uint32_t riff_size;
+  int is_vp8x_chunk = 0;
+  int is_vp8_chunk = 0;
 
-  if (curr_size < WEBP_HEADER_SIZE) {
+  if (curr_size < RIFF_HEADER_SIZE) {
     return VP8_STATUS_SUSPENDED;
   }
 
-  // Validate and Skip over RIFF header
+  if (!WebPCheckAndSkipRIFFHeader(&data, &curr_size, &riff_size)) {
-  chunk_size = WebPCheckRIFFHeader(&data, &curr_size);
+    return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);  // Wrong RIFF Header.
-  if (chunk_size == 0 ||
+  }
-      curr_size < VP8_HEADER_SIZE ||
+
-      !VP8GetInfo(data, curr_size, chunk_size, NULL, NULL, NULL)) {
+  if (!VP8XGetInfo(&data, &curr_size, &is_vp8x_chunk, NULL, NULL, NULL)) {
+    return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);  // Wrong VP8X Chunk.
+  }
+
+  if (is_vp8x_chunk == -1) {
+    return VP8_STATUS_SUSPENDED;  // Not enough data bytes to process chunk.
+  }
+
+  if (!VP8CheckAndSkipHeader(&data, &curr_size, &is_vp8_chunk, &chunk_size,
+                             riff_size)) {
+    return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);  // Invalid VP8 header.
+  }
+
+  if ((is_vp8_chunk == -1) && (chunk_size == 0)){
+    return VP8_STATUS_SUSPENDED;  // Not enough data bytes to extract chunk_size
+  }
+
+  if (curr_size < VP8_HEADER_SIZE) {
+    return VP8_STATUS_SUSPENDED;  // Not enough data bytes to extract VP8 Header
+  }
+
+  if (!VP8GetInfo(data, curr_size, chunk_size, NULL, NULL, NULL)) {
     return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
   }
 

src/dec/vp8.c

@@ -11,11 +11,15 @@
 
 #include <stdlib.h>
 #include "vp8i.h"
+#include "webpi.h"
 
 #if defined(__cplusplus) || defined(c_plusplus)
 extern "C" {
 #endif
 
+#define RIFF_HEADER_SIZE 12
+#define VP8X_HEADER_SIZE 20
+
 //-----------------------------------------------------------------------------
 
 int WebPGetDecoderVersion(void) {
@@ -77,8 +81,40 @@ int VP8SetError(VP8Decoder* const dec,
 
 //-----------------------------------------------------------------------------
 
-int VP8GetInfo(const uint8_t* data,
+static inline uint32_t get_le32(const uint8_t* const data) {
-               uint32_t data_size, uint32_t chunk_size,
+  return data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
+}
+
+int VP8CheckAndSkipHeader(const uint8_t** data_ptr, uint32_t* data_size_ptr,
+                          int* is_vp8_chunk, uint32_t* chunk_size,
+                          uint32_t riff_size) {
+  if (!data_ptr || !data_size_ptr || !is_vp8_chunk || !chunk_size) {
+    return 0;  // Invalid Args.
+  }
+
+  if (*data_size_ptr >= 8) {
+    if (!memcmp(*data_ptr, "VP8 ", 4)) {
+      *is_vp8_chunk = 1;
+      *chunk_size = get_le32(*data_ptr + 4);
+      if ((riff_size >= RIFF_HEADER_SIZE) &&
+          (*chunk_size > riff_size - RIFF_HEADER_SIZE)) {
+        return 0;  // Inconsistent size information.
+      }
+      // We have consumed 8 bytes from VP8 Header. Skip it.
+      *data_ptr += 8;
+      *data_size_ptr -= 8;
+    } else {
+      *is_vp8_chunk = 0;
+      *chunk_size = 0;
+    }
+  } else {
+    *is_vp8_chunk = -1;  // Insufficient data.
+    *chunk_size = 0;
+  }
+  return 1;
+}
+
+int VP8GetInfo(const uint8_t* data, uint32_t data_size, uint32_t chunk_size,
                int* width, int* height, int* has_alpha) {
   if (data_size < 10) {
     return 0;         // not enough data
@@ -125,6 +161,40 @@ int VP8GetInfo(const uint8_t* data,
   }
 }
 
+int VP8XGetInfo(const uint8_t** data_ptr, uint32_t* data_size_ptr,
+                int* is_vp8x_chunk, int* width, int* height, uint32_t* flags) {
+  if (!data_ptr || !data_size_ptr || !is_vp8x_chunk) {
+    return 0;  // Invalid Args.
+  }
+
+  if (*data_size_ptr >= VP8X_HEADER_SIZE) {
+    if (!memcmp(*data_ptr, "VP8X", 4)) {
+      const uint32_t chunk_size = get_le32(*data_ptr + 4);
+      *is_vp8x_chunk = 1;
+      if (chunk_size != (VP8X_HEADER_SIZE - 8)) {
+        return 0;  // Wrong chunk size.
+      }
+      if (flags) {
+        *flags = get_le32(*data_ptr + 8);
+      }
+      if (width) {
+        *width = get_le32(*data_ptr + 12);
+      }
+      if (height) {
+        *height = get_le32(*data_ptr + 16);
+      }
+      // We have consumed 20 bytes from VP8X Header. Skip it.
+      *data_ptr += VP8X_HEADER_SIZE;
+      *data_size_ptr -= VP8X_HEADER_SIZE;
+    } else {
+      *is_vp8x_chunk = 0;
+    }
+  } else {
+    *is_vp8x_chunk = -1;  // Insufficient data.
+  }
+  return 1;
+}
+
 //-----------------------------------------------------------------------------
 // Header parsing
 
@@ -245,14 +315,14 @@ static int ParseFilterHeader(VP8BitReader* br, VP8Decoder* const dec) {
   return !br->eof_;
 }
 
-static inline uint32_t get_le32(const uint8_t* const data) {
-  return data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
-}
-
 // Topmost call
 int VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io) {
-  uint8_t* buf;
+  const uint8_t* buf;
   uint32_t buf_size;
+  uint32_t riff_size;
+  uint32_t chunk_size;
+  int is_vp8x_chunk = 0;
+  int is_vp8_chunk = 0;
   VP8FrameHeader* frm_hdr;
   VP8PictureHeader* pic_hdr;
   VP8BitReader* br;
@@ -274,34 +344,31 @@ int VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io) {
                        "Not enough data to parse frame header");
   }
 
-  // Skip over valid RIFF headers
+  // Skip over valid RIFF headers.
-  if (!memcmp(buf, "RIFF", 4)) {
+  if (!WebPCheckAndSkipRIFFHeader(&buf, &buf_size, &riff_size)) {
-    uint32_t riff_size;
-    uint32_t chunk_size;
-    if (buf_size < 20 + 4) {
-      return VP8SetError(dec, VP8_STATUS_NOT_ENOUGH_DATA,
-                         "RIFF: Truncated header.");
-    }
-    if (memcmp(buf + 8, "WEBP", 4)) {   // wrong image file signature
     return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR,
-                         "RIFF: WEBP signature not found.");
+                       "RIFF: Invalid RIFF container");
   }
-    riff_size = get_le32(buf + 4);
+
-    if (riff_size < 12) {
+  if (!VP8XGetInfo(&buf, &buf_size, &is_vp8x_chunk, NULL, NULL, NULL)) {
-      return VP8SetError(dec, VP8_STATUS_NOT_ENOUGH_DATA,
-                         "RIFF: Truncated header.");
-    }
-    if (memcmp(buf + 12, "VP8 ", 4)) {
     return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR,
-                         "RIFF: Invalid compression format.");
+                       "RIFF: Invalid VP8X container");
   }
-    chunk_size = get_le32(buf + 16);
+
-    if (chunk_size > riff_size - 12) {
+  if (!VP8CheckAndSkipHeader(&buf, &buf_size, &is_vp8_chunk, &chunk_size,
+                             riff_size)) {
     return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR,
                        "RIFF: Inconsistent size information.");
   }
-    buf += 20;
+
-    buf_size -= 20;
+  if (is_vp8_chunk == -1) {
+      return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR,
+                         "Not enough data to parse frame header.");
+  }
+
+  if (buf_size < 4) {
+    return VP8SetError(dec, VP8_STATUS_NOT_ENOUGH_DATA,
+                       "RIFF: Truncated header.");
   }
 
   // Paragraph 9.1
@@ -437,7 +504,7 @@ int VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io) {
   if (dec->pic_hdr_.colorspace_) {
     const size_t kTrailerSize = 8;
     const uint8_t kTrailerMarker = 0x01;
-    uint8_t* const ext_buf = buf - kTrailerSize;
+    const uint8_t* ext_buf = buf - kTrailerSize;
     size_t size;
 
     if (frm_hdr->partition_length_ < kTrailerSize ||

src/dec/vp8i.h

@@ -286,6 +286,20 @@ struct VP8Decoder {
 // in vp8.c
 int VP8SetError(VP8Decoder* const dec,
                 VP8StatusCode error, const char * const msg);
+
+// Validates the VP8 Header and skip over it.
+// Returns 0 for invalid (chunk_size greater than riff_size) VP8 header.
+// Else return 1.
+// is_vp8_chunk is set to:
+//   0, in case data bytes don't correspond to VP8 chunk.
+//   1, in case data bytes correspond to VP8 chunk.
+//   -1, in case not enough bytes (partial VP8 chunk) are passed.
+// chunk_size is set to the chunk size extracted from the VP8 chunk header. For
+// partial VP8 chunk, chunk_size is set to 0.
+int VP8CheckAndSkipHeader(const uint8_t** data_ptr, uint32_t* data_size_ptr,
+                          int* is_vp8_chunk, uint32_t* chunk_size,
+                          uint32_t riff_size);
+
 // Validates the VP8 data-header and retrieve basic header information viz width
 // and height. Returns 0 in case of formatting error. *width/*height/*has_alpha
 // can be passed NULL.
@@ -294,6 +308,17 @@ int VP8GetInfo(const uint8_t* data,
                uint32_t chunk_size,   // total data size expect in the chunk
                int *width, int *height, int *has_alpha);
 
+// Validates the VP8X Header and skip over it.
+// Returns 0 for invalid VP8X header. Else return 1.
+// is_vp8x_chunk is set to:
+//   0, in case data bytes doesn't correspond to VP8X chunk.
+//   1, in case data bytes correspond to VP8X chunk.
+//   -1, in case not enough bytes (partial VP8X chunk) are passed.
+// Width, Height & Flags are set to the corresponding fields extracted from the
+// VP8X chunk.
+int VP8XGetInfo(const uint8_t** data_ptr, uint32_t* data_size_ptr,
+                int* is_vp8x_chunk, int* width, int* height, uint32_t* flags);
+
 // in tree.c
 void VP8ResetProba(VP8Proba* const proba);
 void VP8ParseProba(VP8BitReader* const br, VP8Decoder* const dec);

src/dec/webp.c

@@ -17,16 +17,26 @@
 extern "C" {
 #endif
 
+#define RIFF_HEADER_SIZE 12
+
 //-----------------------------------------------------------------------------
 // RIFF layout is:
 //   0ffset  tag
 //   0...3   "RIFF" 4-byte tag
 //   4...7   size of image data (including metadata) starting at offset 8
 //   8...11  "WEBP"   our form-type signature
+// The RIFF container (12 bytes) is followed by appropriate chunks:
 //   12..15  "VP8 ": 4-bytes tags, describing the raw video format used
 //   16..19  size of the raw VP8 image data, starting at offset 20
 //   20....  the VP8 bytes
-// There can be extra chunks after the "VP8 " chunk (ICMT, ICOP, ...)
+// Or,
+//   12..15  "VP8X": 4-bytes tags, describing the extended-VP8 chunk.
+//   16..19  size of the VP8X chunk starting at offset 8.
+//   20..23  VP8X flags bit-map corresponding to the chunk-types present.
+//   24..27  Width of the Canvas Image.
+//   28..31  Height of the Canvas Image.
+// There can be extra chunks after the "VP8X" chunk (ICCP, TILE, FRM, VP8,
+// META  ...)
 // All 32-bits sizes are in little-endian order.
 // Note: chunk data must be padded to multiple of 2 in size
 
@@ -34,33 +44,25 @@ static inline uint32_t get_le32(const uint8_t* const data) {
   return data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
 }
 
-// If a RIFF container is detected, validate it and skip over it.
+uint32_t WebPCheckAndSkipRIFFHeader(const uint8_t** data_ptr,
-uint32_t WebPCheckRIFFHeader(const uint8_t** data_ptr,
+                                    uint32_t* data_size_ptr,
-                             uint32_t* data_size_ptr) {
+                                    uint32_t* riff_size) {
-  uint32_t chunk_size = 0xffffffffu;
+  if (*data_size_ptr >= RIFF_HEADER_SIZE && !memcmp(*data_ptr, "RIFF", 4)) {
-  if (*data_size_ptr >= 10 + 20 && !memcmp(*data_ptr, "RIFF", 4)) {
     if (memcmp(*data_ptr + 8, "WEBP", 4)) {
-      return 0;  // wrong image file signature
+      return 0;  // Wrong image file signature.
     } else {
-      const uint32_t riff_size = get_le32(*data_ptr + 4);
+      *riff_size = get_le32(*data_ptr + 4);
-      if (riff_size < 12) {
+      if (*riff_size < RIFF_HEADER_SIZE) {
-        return 0;   // we should have at least one chunk
+        return 0;   // We should have at least one chunk.
-      }
-      if (memcmp(*data_ptr + 12, "VP8 ", 4)) {
-        return 0;   // invalid compression format
-      }
-      chunk_size = get_le32(*data_ptr + 16);
-      if (chunk_size > riff_size - 12) {
-        return 0;  // inconsistent size information.
       }
       // We have a RIFF container. Skip it.
-      *data_ptr += 20;
+      *data_ptr += RIFF_HEADER_SIZE;
-      *data_size_ptr -= 20;
+      *data_size_ptr -= RIFF_HEADER_SIZE;
-      // Note: we don't report error for odd-sized chunks.
     }
-    return chunk_size;
+  } else {
+    *riff_size = 0;  // Did not get full RIFF Header.
   }
-  return *data_size_ptr;
+  return 1;
 }
 
 //-----------------------------------------------------------------------------
@@ -268,19 +270,6 @@ uint8_t* WebPDecodeYUV(const uint8_t* data, uint32_t data_size,
   return out;
 }
 
-//-----------------------------------------------------------------------------
-// WebPGetInfo()
-
-int WebPGetInfo(const uint8_t* data, uint32_t data_size,
-                int* width, int* height) {
-  const uint32_t chunk_size = WebPCheckRIFFHeader(&data, &data_size);
-  if (!chunk_size) {
-    return 0;         // unsupported RIFF header
-  }
-  // Validate raw video data
-  return VP8GetInfo(data, data_size, chunk_size, width, height, NULL);
-}
-
 static void DefaultFeatures(WebPBitstreamFeatures* const features) {
   assert(features);
   memset(features, 0, sizeof(*features));
@@ -289,25 +278,77 @@ static void DefaultFeatures(WebPBitstreamFeatures* const features) {
 
 static VP8StatusCode GetFeatures(const uint8_t** data, uint32_t* data_size,
                                  WebPBitstreamFeatures* const features) {
-  uint32_t chunk_size;
+  uint32_t chunk_size = 0;
+  uint32_t riff_size = 0;
+  uint32_t flags = 0;
+  int is_vp8x_chunk = 0;
+  int is_vp8_chunk = 0;
+
   if (features == NULL) {
     return VP8_STATUS_INVALID_PARAM;
   }
   DefaultFeatures(features);
+
   if (data == NULL || *data == NULL || data_size == 0) {
     return VP8_STATUS_INVALID_PARAM;
   }
-  chunk_size = WebPCheckRIFFHeader(data, data_size);
+
-  if (chunk_size == 0) {
+  if (!WebPCheckAndSkipRIFFHeader(data, data_size, &riff_size)) {
-    return VP8_STATUS_BITSTREAM_ERROR;   // unsupported RIFF header
+    return VP8_STATUS_BITSTREAM_ERROR;   // Wrong RIFF Header.
   }
+
+  if (!VP8XGetInfo(data, data_size, &is_vp8x_chunk,
+                   &features->width, &features->height, &flags)) {
+    return VP8_STATUS_BITSTREAM_ERROR;  // Wrong VP8X Chunk-header.
+  }
+
+  if (is_vp8x_chunk > 0) {
+    return VP8_STATUS_OK;
+  }
+
+  if (!VP8CheckAndSkipHeader(data, data_size, &is_vp8_chunk, &chunk_size,
+                             riff_size)) {
+    return VP8_STATUS_BITSTREAM_ERROR;  // Invalid VP8 header.
+  }
+
+  if (is_vp8_chunk == -1) {
+    return VP8_STATUS_BITSTREAM_ERROR;   // Insufficient data-bytes.
+  }
+
+  if (!is_vp8_chunk) {
+    chunk_size = *data_size;  // No VP8 chunk wrapper over raw VP8 data.
+  }
+
+  // Validates raw VP8 data.
   if (!VP8GetInfo(*data, *data_size, chunk_size,
                   &features->width, &features->height, &features->has_alpha)) {
     return VP8_STATUS_BITSTREAM_ERROR;
   }
+
   return VP8_STATUS_OK;
 }
 
+//-----------------------------------------------------------------------------
+// WebPGetInfo()
+
+int WebPGetInfo(const uint8_t* data, uint32_t data_size,
+                int* width, int* height) {
+  WebPBitstreamFeatures features;
+
+  if (GetFeatures(&data, &data_size, &features) != VP8_STATUS_OK) {
+    return 0;
+  }
+
+  if (width) {
+    *width  = features.width;
+  }
+  if (height) {
+    *height = features.height;
+  }
+
+  return 1;
+}
+
 //-----------------------------------------------------------------------------
 // Advance decoding API
 

src/dec/webpi.h

@@ -76,10 +76,13 @@ void WebPInitUpsamplersSSE2(void);
 //------------------------------------------------------------------------------
 // Misc utils
 
-// If a RIFF container is detected, validate it and skip over it. Returns
+// Validates the RIFF container (if detected) and skip over it.
-// VP8 bit-stream size if RIFF header is valid else returns 0
+// If a RIFF container is detected, returns 0 for invalid header. Else return 1.
-uint32_t WebPCheckRIFFHeader(const uint8_t** data_ptr,
+// In case there are not enough bytes (partial RIFF container), return 0 for
-                             uint32_t* data_size_ptr);
+// riff_size. Else return the riff_size extracted from the header.
+uint32_t WebPCheckAndSkipRIFFHeader(const uint8_t** data_ptr,
+                                    uint32_t* data_size_ptr,
+                                    uint32_t* riff_size_ptr);
 
 // Initializes VP8Io with custom setup, io and teardown functions. The default
 // hooks will use the supplied 'params' as io->opaque handle.