blob: ea7eea904dd50f7cdcce6b0c338f4ed2662033e6 [file] [log] [blame]
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "media/webm/webm_parser.h"
// This file contains code to parse WebM file elements. It was created
// from information in the Matroska spec.
// http://www.matroska.org/technical/specs/index.html
#include <iomanip>
#include "base/logging.h"
#include "media/webm/webm_constants.h"
namespace media {
enum ElementType {
UNKNOWN,
LIST, // Referred to as Master Element in the Matroska spec.
UINT,
FLOAT,
BINARY,
STRING,
SBLOCK,
SKIP,
};
struct ElementIdInfo {
ElementType type_;
int id_;
};
struct ListElementInfo {
int id_;
int level_;
const ElementIdInfo* id_info_;
int id_info_count_;
};
// The following are tables indicating what IDs are valid sub-elements
// of particular elements. If an element is encountered that doesn't
// appear in the list, a parsing error is signalled. Some elements are
// marked as SKIP because they are valid, but we don't care about them
// right now.
static const ElementIdInfo kEBMLHeaderIds[] = {
{UINT, kWebMIdEBMLVersion},
{UINT, kWebMIdEBMLReadVersion},
{UINT, kWebMIdEBMLMaxIDLength},
{UINT, kWebMIdEBMLMaxSizeLength},
{STRING, kWebMIdDocType},
{UINT, kWebMIdDocTypeVersion},
{UINT, kWebMIdDocTypeReadVersion},
};
static const ElementIdInfo kSegmentIds[] = {
{LIST, kWebMIdSeekHead},
{LIST, kWebMIdInfo},
{LIST, kWebMIdCluster},
{LIST, kWebMIdTracks},
{LIST, kWebMIdCues},
{LIST, kWebMIdAttachments},
{LIST, kWebMIdChapters},
{LIST, kWebMIdTags},
};
static const ElementIdInfo kSeekHeadIds[] = {
{LIST, kWebMIdSeek},
};
static const ElementIdInfo kSeekIds[] = {
{BINARY, kWebMIdSeekID},
{UINT, kWebMIdSeekPosition},
};
static const ElementIdInfo kInfoIds[] = {
{BINARY, kWebMIdSegmentUID},
{STRING, kWebMIdSegmentFilename},
{BINARY, kWebMIdPrevUID},
{STRING, kWebMIdPrevFilename},
{BINARY, kWebMIdNextUID},
{STRING, kWebMIdNextFilename},
{BINARY, kWebMIdSegmentFamily},
{LIST, kWebMIdChapterTranslate},
{UINT, kWebMIdTimecodeScale},
{FLOAT, kWebMIdDuration},
{BINARY, kWebMIdDateUTC},
{STRING, kWebMIdTitle},
{STRING, kWebMIdMuxingApp},
{STRING, kWebMIdWritingApp},
};
static const ElementIdInfo kChapterTranslateIds[] = {
{UINT, kWebMIdChapterTranslateEditionUID},
{UINT, kWebMIdChapterTranslateCodec},
{BINARY, kWebMIdChapterTranslateID},
};
static const ElementIdInfo kClusterIds[] = {
{SBLOCK, kWebMIdSimpleBlock},
{UINT, kWebMIdTimecode},
{LIST, kWebMIdSilentTracks},
{UINT, kWebMIdPosition},
{UINT, kWebMIdPrevSize},
{LIST, kWebMIdBlockGroup},
};
static const ElementIdInfo kSilentTracksIds[] = {
{UINT, kWebMIdSilentTrackNumber},
};
static const ElementIdInfo kBlockGroupIds[] = {
{BINARY, kWebMIdBlock},
{LIST, kWebMIdBlockAdditions},
{UINT, kWebMIdBlockDuration},
{UINT, kWebMIdReferencePriority},
{BINARY, kWebMIdReferenceBlock},
{BINARY, kWebMIdCodecState},
{LIST, kWebMIdSlices},
};
static const ElementIdInfo kBlockAdditionsIds[] = {
{LIST, kWebMIdBlockMore},
};
static const ElementIdInfo kBlockMoreIds[] = {
{UINT, kWebMIdBlockAddID},
{BINARY, kWebMIdBlockAdditional},
};
static const ElementIdInfo kSlicesIds[] = {
{LIST, kWebMIdTimeSlice},
};
static const ElementIdInfo kTimeSliceIds[] = {
{UINT, kWebMIdLaceNumber},
};
static const ElementIdInfo kTracksIds[] = {
{LIST, kWebMIdTrackEntry},
};
static const ElementIdInfo kTrackEntryIds[] = {
{UINT, kWebMIdTrackNumber},
{UINT, kWebMIdTrackUID},
{UINT, kWebMIdTrackType},
{UINT, kWebMIdFlagEnabled},
{UINT, kWebMIdFlagDefault},
{UINT, kWebMIdFlagForced},
{UINT, kWebMIdFlagLacing},
{UINT, kWebMIdMinCache},
{UINT, kWebMIdMaxCache},
{UINT, kWebMIdDefaultDuration},
{FLOAT, kWebMIdTrackTimecodeScale},
{UINT, kWebMIdMaxBlockAdditionId},
{STRING, kWebMIdName},
{STRING, kWebMIdLanguage},
{STRING, kWebMIdCodecID},
{BINARY, kWebMIdCodecPrivate},
{STRING, kWebMIdCodecName},
{UINT, kWebMIdAttachmentLink},
{UINT, kWebMIdCodecDecodeAll},
{UINT, kWebMIdTrackOverlay},
{LIST, kWebMIdTrackTranslate},
{LIST, kWebMIdVideo},
{LIST, kWebMIdAudio},
{LIST, kWebMIdTrackOperation},
{LIST, kWebMIdContentEncodings},
};
static const ElementIdInfo kTrackTranslateIds[] = {
{UINT, kWebMIdTrackTranslateEditionUID},
{UINT, kWebMIdTrackTranslateCodec},
{BINARY, kWebMIdTrackTranslateTrackID},
};
static const ElementIdInfo kVideoIds[] = {
{UINT, kWebMIdFlagInterlaced},
{UINT, kWebMIdStereoMode},
{UINT, kWebMIdPixelWidth},
{UINT, kWebMIdPixelHeight},
{UINT, kWebMIdPixelCropBottom},
{UINT, kWebMIdPixelCropTop},
{UINT, kWebMIdPixelCropLeft},
{UINT, kWebMIdPixelCropRight},
{UINT, kWebMIdDisplayWidth},
{UINT, kWebMIdDisplayHeight},
{UINT, kWebMIdDisplayUnit},
{UINT, kWebMIdAspectRatioType},
{BINARY, kWebMIdColorSpace},
};
static const ElementIdInfo kAudioIds[] = {
{FLOAT, kWebMIdSamplingFrequency},
{FLOAT, kWebMIdOutputSamplingFrequency},
{UINT, kWebMIdChannels},
{UINT, kWebMIdBitDepth},
};
static const ElementIdInfo kTrackOperationIds[] = {
{LIST, kWebMIdTrackCombinePlanes},
{LIST, kWebMIdJoinBlocks},
};
static const ElementIdInfo kTrackCombinePlanesIds[] = {
{LIST, kWebMIdTrackPlane},
};
static const ElementIdInfo kTrackPlaneIds[] = {
{UINT, kWebMIdTrackPlaneUID},
{UINT, kWebMIdTrackPlaneType},
};
static const ElementIdInfo kJoinBlocksIds[] = {
{UINT, kWebMIdTrackJoinUID},
};
static const ElementIdInfo kContentEncodingsIds[] = {
{LIST, kWebMIdContentEncoding},
};
static const ElementIdInfo kContentEncodingIds[] = {
{UINT, kWebMIdContentEncodingOrder},
{UINT, kWebMIdContentEncodingScope},
{UINT, kWebMIdContentEncodingType},
{LIST, kWebMIdContentCompression},
{LIST, kWebMIdContentEncryption},
};
static const ElementIdInfo kContentCompressionIds[] = {
{UINT, kWebMIdContentCompAlgo},
{BINARY, kWebMIdContentCompSettings},
};
static const ElementIdInfo kContentEncryptionIds[] = {
{UINT, kWebMIdContentEncAlgo},
{BINARY, kWebMIdContentEncKeyID},
{BINARY, kWebMIdContentSignature},
{BINARY, kWebMIdContentSigKeyID},
{UINT, kWebMIdContentSigAlgo},
{UINT, kWebMIdContentSigHashAlgo},
};
static const ElementIdInfo kCuesIds[] = {
{LIST, kWebMIdCuePoint},
};
static const ElementIdInfo kCuePointIds[] = {
{UINT, kWebMIdCueTime},
{LIST, kWebMIdCueTrackPositions},
};
static const ElementIdInfo kCueTrackPositionsIds[] = {
{UINT, kWebMIdCueTrack},
{UINT, kWebMIdCueClusterPosition},
{UINT, kWebMIdCueBlockNumber},
{UINT, kWebMIdCueCodecState},
{LIST, kWebMIdCueReference},
};
static const ElementIdInfo kCueReferenceIds[] = {
{UINT, kWebMIdCueRefTime},
};
static const ElementIdInfo kAttachmentsIds[] = {
{LIST, kWebMIdAttachedFile},
};
static const ElementIdInfo kAttachedFileIds[] = {
{STRING, kWebMIdFileDescription},
{STRING, kWebMIdFileName},
{STRING, kWebMIdFileMimeType},
{BINARY, kWebMIdFileData},
{UINT, kWebMIdFileUID},
};
static const ElementIdInfo kChaptersIds[] = {
{LIST, kWebMIdEditionEntry},
};
static const ElementIdInfo kEditionEntryIds[] = {
{UINT, kWebMIdEditionUID},
{UINT, kWebMIdEditionFlagHidden},
{UINT, kWebMIdEditionFlagDefault},
{UINT, kWebMIdEditionFlagOrdered},
{LIST, kWebMIdChapterAtom},
};
static const ElementIdInfo kChapterAtomIds[] = {
{UINT, kWebMIdChapterUID},
{UINT, kWebMIdChapterTimeStart},
{UINT, kWebMIdChapterTimeEnd},
{UINT, kWebMIdChapterFlagHidden},
{UINT, kWebMIdChapterFlagEnabled},
{BINARY, kWebMIdChapterSegmentUID},
{UINT, kWebMIdChapterSegmentEditionUID},
{UINT, kWebMIdChapterPhysicalEquiv},
{LIST, kWebMIdChapterTrack},
{LIST, kWebMIdChapterDisplay},
{LIST, kWebMIdChapProcess},
};
static const ElementIdInfo kChapterTrackIds[] = {
{UINT, kWebMIdChapterTrackNumber},
};
static const ElementIdInfo kChapterDisplayIds[] = {
{STRING, kWebMIdChapString},
{STRING, kWebMIdChapLanguage},
{STRING, kWebMIdChapCountry},
};
static const ElementIdInfo kChapProcessIds[] = {
{UINT, kWebMIdChapProcessCodecID},
{BINARY, kWebMIdChapProcessPrivate},
{LIST, kWebMIdChapProcessCommand},
};
static const ElementIdInfo kChapProcessCommandIds[] = {
{UINT, kWebMIdChapProcessTime},
{BINARY, kWebMIdChapProcessData},
};
static const ElementIdInfo kTagsIds[] = {
{LIST, kWebMIdTag},
};
static const ElementIdInfo kTagIds[] = {
{LIST, kWebMIdTargets},
{LIST, kWebMIdSimpleTag},
};
static const ElementIdInfo kTargetsIds[] = {
{UINT, kWebMIdTargetTypeValue},
{STRING, kWebMIdTargetType},
{UINT, kWebMIdTagTrackUID},
{UINT, kWebMIdTagEditionUID},
{UINT, kWebMIdTagChapterUID},
{UINT, kWebMIdTagAttachmentUID},
};
static const ElementIdInfo kSimpleTagIds[] = {
{STRING, kWebMIdTagName},
{STRING, kWebMIdTagLanguage},
{UINT, kWebMIdTagDefault},
{STRING, kWebMIdTagString},
{BINARY, kWebMIdTagBinary},
};
#define LIST_ELEMENT_INFO(id, level, id_info) \
{ (id), (level), (id_info), arraysize(id_info) }
static const ListElementInfo kListElementInfo[] = {
LIST_ELEMENT_INFO(kWebMIdCluster, 1, kClusterIds),
LIST_ELEMENT_INFO(kWebMIdEBMLHeader, 0, kEBMLHeaderIds),
LIST_ELEMENT_INFO(kWebMIdSegment, 0, kSegmentIds),
LIST_ELEMENT_INFO(kWebMIdSeekHead, 1, kSeekHeadIds),
LIST_ELEMENT_INFO(kWebMIdSeek, 2, kSeekIds),
LIST_ELEMENT_INFO(kWebMIdInfo, 1, kInfoIds),
LIST_ELEMENT_INFO(kWebMIdChapterTranslate, 2, kChapterTranslateIds),
LIST_ELEMENT_INFO(kWebMIdSilentTracks, 2, kSilentTracksIds),
LIST_ELEMENT_INFO(kWebMIdBlockGroup, 2, kBlockGroupIds),
LIST_ELEMENT_INFO(kWebMIdBlockAdditions, 3, kBlockAdditionsIds),
LIST_ELEMENT_INFO(kWebMIdBlockMore, 4, kBlockMoreIds),
LIST_ELEMENT_INFO(kWebMIdSlices, 3, kSlicesIds),
LIST_ELEMENT_INFO(kWebMIdTimeSlice, 4, kTimeSliceIds),
LIST_ELEMENT_INFO(kWebMIdTracks, 1, kTracksIds),
LIST_ELEMENT_INFO(kWebMIdTrackEntry, 2, kTrackEntryIds),
LIST_ELEMENT_INFO(kWebMIdTrackTranslate, 3, kTrackTranslateIds),
LIST_ELEMENT_INFO(kWebMIdVideo, 3, kVideoIds),
LIST_ELEMENT_INFO(kWebMIdAudio, 3, kAudioIds),
LIST_ELEMENT_INFO(kWebMIdTrackOperation, 3, kTrackOperationIds),
LIST_ELEMENT_INFO(kWebMIdTrackCombinePlanes, 4, kTrackCombinePlanesIds),
LIST_ELEMENT_INFO(kWebMIdTrackPlane, 5, kTrackPlaneIds),
LIST_ELEMENT_INFO(kWebMIdJoinBlocks, 4, kJoinBlocksIds),
LIST_ELEMENT_INFO(kWebMIdContentEncodings, 3, kContentEncodingsIds),
LIST_ELEMENT_INFO(kWebMIdContentEncoding, 4, kContentEncodingIds),
LIST_ELEMENT_INFO(kWebMIdContentCompression, 5, kContentCompressionIds),
LIST_ELEMENT_INFO(kWebMIdContentEncryption, 5, kContentEncryptionIds),
LIST_ELEMENT_INFO(kWebMIdCues, 1, kCuesIds),
LIST_ELEMENT_INFO(kWebMIdCuePoint, 2, kCuePointIds),
LIST_ELEMENT_INFO(kWebMIdCueTrackPositions, 3, kCueTrackPositionsIds),
LIST_ELEMENT_INFO(kWebMIdCueReference, 4, kCueReferenceIds),
LIST_ELEMENT_INFO(kWebMIdAttachments, 1, kAttachmentsIds),
LIST_ELEMENT_INFO(kWebMIdAttachedFile, 2, kAttachedFileIds),
LIST_ELEMENT_INFO(kWebMIdChapters, 1, kChaptersIds),
LIST_ELEMENT_INFO(kWebMIdEditionEntry, 2, kEditionEntryIds),
LIST_ELEMENT_INFO(kWebMIdChapterAtom, 3, kChapterAtomIds),
LIST_ELEMENT_INFO(kWebMIdChapterTrack, 4, kChapterTrackIds),
LIST_ELEMENT_INFO(kWebMIdChapterDisplay, 4, kChapterDisplayIds),
LIST_ELEMENT_INFO(kWebMIdChapProcess, 4, kChapProcessIds),
LIST_ELEMENT_INFO(kWebMIdChapProcessCommand, 5, kChapProcessCommandIds),
LIST_ELEMENT_INFO(kWebMIdTags, 1, kTagsIds),
LIST_ELEMENT_INFO(kWebMIdTag, 2, kTagIds),
LIST_ELEMENT_INFO(kWebMIdTargets, 3, kTargetsIds),
LIST_ELEMENT_INFO(kWebMIdSimpleTag, 3, kSimpleTagIds),
};
// Parses an element header id or size field. These fields are variable length
// encoded. The first byte indicates how many bytes the field occupies.
// |buf| - The buffer to parse.
// |size| - The number of bytes in |buf|
// |max_bytes| - The maximum number of bytes the field can be. ID fields
// set this to 4 & element size fields set this to 8. If the
// first byte indicates a larger field size than this it is a
// parser error.
// |mask_first_byte| - For element size fields the field length encoding bits
// need to be masked off. This parameter is true for
// element size fields and is false for ID field values.
//
// Returns: The number of bytes parsed on success. -1 on error.
static int ParseWebMElementHeaderField(const uint8* buf, int size,
int max_bytes, bool mask_first_byte,
int64* num) {
DCHECK(buf);
DCHECK(num);
if (size < 0)
return -1;
if (size == 0)
return 0;
int mask = 0x80;
uint8 ch = buf[0];
int extra_bytes = -1;
bool all_ones = false;
for (int i = 0; i < max_bytes; ++i) {
if ((ch & mask) != 0) {
mask = ~mask & 0xff;
*num = mask_first_byte ? ch & mask : ch;
all_ones = (ch & mask) == mask;
extra_bytes = i;
break;
}
mask = 0x80 | mask >> 1;
}
if (extra_bytes == -1)
return -1;
// Return 0 if we need more data.
if ((1 + extra_bytes) > size)
return 0;
int bytes_used = 1;
for (int i = 0; i < extra_bytes; ++i) {
ch = buf[bytes_used++];
all_ones &= (ch == 0xff);
*num = (*num << 8) | ch;
}
if (all_ones)
*num = kint64max;
return bytes_used;
}
int WebMParseElementHeader(const uint8* buf, int size,
int* id, int64* element_size) {
DCHECK(buf);
DCHECK_GE(size, 0);
DCHECK(id);
DCHECK(element_size);
if (size == 0)
return 0;
int64 tmp = 0;
int num_id_bytes = ParseWebMElementHeaderField(buf, size, 4, false, &tmp);
if (num_id_bytes <= 0)
return num_id_bytes;
if (tmp == kint64max)
tmp = kWebMReservedId;
*id = static_cast<int>(tmp);
int num_size_bytes = ParseWebMElementHeaderField(buf + num_id_bytes,
size - num_id_bytes,
8, true, &tmp);
if (num_size_bytes <= 0)
return num_size_bytes;
if (tmp == kint64max)
tmp = kWebMUnknownSize;
*element_size = tmp;
DVLOG(3) << "WebMParseElementHeader() : id " << std::hex << *id << std::dec
<< " size " << *element_size;
return num_id_bytes + num_size_bytes;
}
// Finds ElementType for a specific ID.
static ElementType FindIdType(int id,
const ElementIdInfo* id_info,
int id_info_count) {
// Check for global element IDs that can be anywhere.
if (id == kWebMIdVoid || id == kWebMIdCRC32)
return SKIP;
for (int i = 0; i < id_info_count; ++i) {
if (id == id_info[i].id_)
return id_info[i].type_;
}
return UNKNOWN;
}
// Finds ListElementInfo for a specific ID.
static const ListElementInfo* FindListInfo(int id) {
for (size_t i = 0; i < arraysize(kListElementInfo); ++i) {
if (id == kListElementInfo[i].id_)
return &kListElementInfo[i];
}
return NULL;
}
static int FindListLevel(int id) {
const ListElementInfo* list_info = FindListInfo(id);
if (list_info)
return list_info->level_;
return -1;
}
static int ParseSimpleBlock(const uint8* buf, int size,
WebMParserClient* client) {
if (size < 4)
return -1;
// Return an error if the trackNum > 127. We just aren't
// going to support large track numbers right now.
if ((buf[0] & 0x80) != 0x80) {
DVLOG(1) << "TrackNumber over 127 not supported";
return -1;
}
int track_num = buf[0] & 0x7f;
int timecode = buf[1] << 8 | buf[2];
int flags = buf[3] & 0xff;
int lacing = (flags >> 1) & 0x3;
if (lacing != 0) {
DVLOG(1) << "Lacing " << lacing << " not supported yet.";
return -1;
}
// Sign extend negative timecode offsets.
if (timecode & 0x8000)
timecode |= (-1 << 16);
const uint8* frame_data = buf + 4;
int frame_size = size - (frame_data - buf);
if (!client->OnSimpleBlock(track_num, timecode, flags,
frame_data, frame_size)) {
return -1;
}
return size;
}
static int ParseUInt(const uint8* buf, int size, int id,
WebMParserClient* client) {
if ((size <= 0) || (size > 8))
return -1;
// Read in the big-endian integer.
int64 value = 0;
for (int i = 0; i < size; ++i)
value = (value << 8) | buf[i];
if (!client->OnUInt(id, value))
return -1;
return size;
}
static int ParseFloat(const uint8* buf, int size, int id,
WebMParserClient* client) {
if ((size != 4) && (size != 8))
return -1;
double value = -1;
// Read the bytes from big-endian form into a native endian integer.
int64 tmp = 0;
for (int i = 0; i < size; ++i)
tmp = (tmp << 8) | buf[i];
// Use a union to convert the integer bit pattern into a floating point
// number.
if (size == 4) {
union {
int32 src;
float dst;
} tmp2;
tmp2.src = static_cast<int32>(tmp);
value = tmp2.dst;
} else if (size == 8) {
union {
int64 src;
double dst;
} tmp2;
tmp2.src = tmp;
value = tmp2.dst;
} else {
return -1;
}
if (!client->OnFloat(id, value))
return -1;
return size;
}
static int ParseBinary(const uint8* buf, int size, int id,
WebMParserClient* client) {
return client->OnBinary(id, buf, size) ? size : -1;
}
static int ParseString(const uint8* buf, int size, int id,
WebMParserClient* client) {
std::string str(reinterpret_cast<const char*>(buf), size);
return client->OnString(id, str) ? size : -1;
}
static int ParseNonListElement(ElementType type, int id, int64 element_size,
const uint8* buf, int size,
WebMParserClient* client) {
DCHECK_GE(size, element_size);
int result = -1;
switch(type) {
case SBLOCK:
result = ParseSimpleBlock(buf, element_size, client);
break;
case LIST:
NOTIMPLEMENTED();
result = -1;
break;
case UINT:
result = ParseUInt(buf, element_size, id, client);
break;
case FLOAT:
result = ParseFloat(buf, element_size, id, client);
break;
case BINARY:
result = ParseBinary(buf, element_size, id, client);
break;
case STRING:
result = ParseString(buf, element_size, id, client);
break;
case SKIP:
result = element_size;
break;
default:
DVLOG(1) << "Unhandled ID type " << type;
return -1;
};
DCHECK_LE(result, size);
return result;
}
WebMParserClient::WebMParserClient() {}
WebMParserClient::~WebMParserClient() {}
WebMParserClient* WebMParserClient::OnListStart(int id) {
DVLOG(1) << "Unexpected list element start with ID " << std::hex << id;
return NULL;
}
bool WebMParserClient::OnListEnd(int id) {
DVLOG(1) << "Unexpected list element end with ID " << std::hex << id;
return false;
}
bool WebMParserClient::OnUInt(int id, int64 val) {
DVLOG(1) << "Unexpected unsigned integer element with ID " << std::hex << id;
return false;
}
bool WebMParserClient::OnFloat(int id, double val) {
DVLOG(1) << "Unexpected float element with ID " << std::hex << id;
return false;
}
bool WebMParserClient::OnBinary(int id, const uint8* data, int size) {
DVLOG(1) << "Unexpected binary element with ID " << std::hex << id;
return false;
}
bool WebMParserClient::OnString(int id, const std::string& str) {
DVLOG(1) << "Unexpected string element with ID " << std::hex << id;
return false;
}
bool WebMParserClient::OnSimpleBlock(int track_num, int timecode, int flags,
const uint8* data, int size) {
DVLOG(1) << "Unexpected simple block element";
return false;
}
WebMListParser::WebMListParser(int id, WebMParserClient* client)
: state_(NEED_LIST_HEADER),
root_id_(id),
root_level_(FindListLevel(id)),
root_client_(client) {
DCHECK_GE(root_level_, 0);
DCHECK(client);
}
WebMListParser::~WebMListParser() {}
void WebMListParser::Reset() {
ChangeState(NEED_LIST_HEADER);
list_state_stack_.clear();
}
int WebMListParser::Parse(const uint8* buf, int size) {
DCHECK(buf);
if (size < 0 || state_ == PARSE_ERROR || state_ == DONE_PARSING_LIST)
return -1;
if (size == 0)
return 0;
const uint8* cur = buf;
int cur_size = size;
int bytes_parsed = 0;
while (cur_size > 0 && state_ != PARSE_ERROR && state_ != DONE_PARSING_LIST) {
int element_id = 0;
int64 element_size = 0;
int result = WebMParseElementHeader(cur, cur_size, &element_id,
&element_size);
if (result < 0)
return result;
if (result == 0)
return bytes_parsed;
switch(state_) {
case NEED_LIST_HEADER: {
if (element_id != root_id_) {
ChangeState(PARSE_ERROR);
return -1;
}
// Only allow Segment & Cluster to have an unknown size.
if (element_size == kWebMUnknownSize &&
(element_id != kWebMIdSegment) &&
(element_id != kWebMIdCluster)) {
ChangeState(PARSE_ERROR);
return -1;
}
ChangeState(INSIDE_LIST);
if (!OnListStart(root_id_, element_size))
return -1;
break;
}
case INSIDE_LIST: {
int header_size = result;
const uint8* element_data = cur + header_size;
int element_data_size = cur_size - header_size;
if (element_size < element_data_size)
element_data_size = element_size;
result = ParseListElement(header_size, element_id, element_size,
element_data, element_data_size);
DCHECK_LE(result, header_size + element_data_size);
if (result < 0) {
ChangeState(PARSE_ERROR);
return -1;
}
if (result == 0)
return bytes_parsed;
break;
}
case DONE_PARSING_LIST:
case PARSE_ERROR:
// Shouldn't be able to get here.
NOTIMPLEMENTED();
break;
}
cur += result;
cur_size -= result;
bytes_parsed += result;
}
return (state_ == PARSE_ERROR) ? -1 : bytes_parsed;
}
bool WebMListParser::IsParsingComplete() const {
return state_ == DONE_PARSING_LIST;
}
void WebMListParser::ChangeState(State new_state) {
state_ = new_state;
}
int WebMListParser::ParseListElement(int header_size,
int id, int64 element_size,
const uint8* data, int size) {
DCHECK_GT(list_state_stack_.size(), 0u);
ListState& list_state = list_state_stack_.back();
DCHECK(list_state.element_info_);
const ListElementInfo* element_info = list_state.element_info_;
ElementType id_type =
FindIdType(id, element_info->id_info_, element_info->id_info_count_);
// Unexpected ID.
if (id_type == UNKNOWN) {
if (list_state.size_ != kWebMUnknownSize ||
!IsSiblingOrAncestor(list_state.id_, id)) {
DVLOG(1) << "No ElementType info for ID 0x" << std::hex << id;
return -1;
}
// We've reached the end of a list of unknown size. Update the size now that
// we know it and dispatch the end of list calls.
list_state.size_ = list_state.bytes_parsed_;
if (!OnListEnd())
return -1;
// Check to see if all open lists have ended.
if (list_state_stack_.size() == 0)
return 0;
list_state = list_state_stack_.back();
}
// Make sure the whole element can fit inside the current list.
int64 total_element_size = header_size + element_size;
if (list_state.size_ != kWebMUnknownSize &&
list_state.size_ < list_state.bytes_parsed_ + total_element_size) {
return -1;
}
if (id_type == LIST) {
list_state.bytes_parsed_ += header_size;
if (!OnListStart(id, element_size))
return -1;
return header_size;
}
// Make sure we have the entire element before trying to parse a non-list
// element.
if (size < element_size)
return 0;
int bytes_parsed = ParseNonListElement(id_type, id, element_size,
data, size, list_state.client_);
DCHECK_LE(bytes_parsed, size);
// Return if an error occurred or we need more data.
// Note: bytes_parsed is 0 for a successful parse of a size 0 element. We
// need to check the element_size to disambiguate the "need more data" case
// from a successful parse.
if (bytes_parsed < 0 || (bytes_parsed == 0 && element_size != 0))
return bytes_parsed;
int result = header_size + bytes_parsed;
list_state.bytes_parsed_ += result;
// See if we have reached the end of the current list.
if (list_state.bytes_parsed_ == list_state.size_) {
if (!OnListEnd())
return -1;
}
return result;
}
bool WebMListParser::OnListStart(int id, int64 size) {
const ListElementInfo* element_info = FindListInfo(id);
if (!element_info)
return false;
int current_level = root_level_ + list_state_stack_.size() - 1;
if (current_level + 1 != element_info->level_)
return false;
WebMParserClient* current_list_client = NULL;
if (!list_state_stack_.empty()) {
// Make sure the new list doesn't go past the end of the current list.
ListState current_list_state = list_state_stack_.back();
if (current_list_state.size_ != kWebMUnknownSize &&
current_list_state.size_ < current_list_state.bytes_parsed_ + size)
return false;
current_list_client = current_list_state.client_;
} else {
current_list_client = root_client_;
}
WebMParserClient* new_list_client = current_list_client->OnListStart(id);
if (!new_list_client)
return false;
ListState new_list_state = { id, size, 0, element_info, new_list_client };
list_state_stack_.push_back(new_list_state);
if (size == 0)
return OnListEnd();
return true;
}
bool WebMListParser::OnListEnd() {
int lists_ended = 0;
for (; !list_state_stack_.empty(); ++lists_ended) {
const ListState& list_state = list_state_stack_.back();
if (list_state.bytes_parsed_ != list_state.size_)
break;
list_state_stack_.pop_back();
int64 bytes_parsed = list_state.bytes_parsed_;
WebMParserClient* client = NULL;
if (!list_state_stack_.empty()) {
// Update the bytes_parsed_ for the parent element.
list_state_stack_.back().bytes_parsed_ += bytes_parsed;
client = list_state_stack_.back().client_;
} else {
client = root_client_;
}
if (!client->OnListEnd(list_state.id_))
return false;
}
DCHECK_GE(lists_ended, 1);
if (list_state_stack_.empty())
ChangeState(DONE_PARSING_LIST);
return true;
}
bool WebMListParser::IsSiblingOrAncestor(int id_a, int id_b) const {
DCHECK((id_a == kWebMIdSegment) || (id_a == kWebMIdCluster));
if (id_a == kWebMIdCluster) {
// kWebMIdCluster siblings.
for (size_t i = 0; i < arraysize(kSegmentIds); i++) {
if (kSegmentIds[i].id_ == id_b)
return true;
}
}
// kWebMIdSegment siblings.
return ((id_b == kWebMIdSegment) || (id_b == kWebMIdEBMLHeader));
}
} // namespace media