1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "media/formats/webm/webm_webvtt_parser.h" 6 7 namespace media { 8 9 void WebMWebVTTParser::Parse(const uint8* payload, int payload_size, 10 std::string* id, 11 std::string* settings, 12 std::string* content) { 13 WebMWebVTTParser parser(payload, payload_size); 14 parser.Parse(id, settings, content); 15 } 16 17 WebMWebVTTParser::WebMWebVTTParser(const uint8* payload, int payload_size) 18 : ptr_(payload), 19 ptr_end_(payload + payload_size) { 20 } 21 22 void WebMWebVTTParser::Parse(std::string* id, 23 std::string* settings, 24 std::string* content) { 25 ParseLine(id); 26 ParseLine(settings); 27 content->assign(ptr_, ptr_end_); 28 } 29 30 bool WebMWebVTTParser::GetByte(uint8* byte) { 31 if (ptr_ >= ptr_end_) 32 return false; // indicates end-of-stream 33 34 *byte = *ptr_++; 35 return true; 36 } 37 38 void WebMWebVTTParser::UngetByte() { 39 --ptr_; 40 } 41 42 void WebMWebVTTParser::ParseLine(std::string* line) { 43 line->clear(); 44 45 // Consume characters from the stream, until we reach end-of-line. 46 47 // The WebVTT spec states that lines may be terminated in any of the following 48 // three ways: 49 // LF 50 // CR 51 // CR LF 52 53 // The spec is here: 54 // http://wiki.webmproject.org/webm-metadata/temporal-metadata/webvtt-in-webm 55 56 enum { 57 kLF = '\x0A', 58 kCR = '\x0D' 59 }; 60 61 for (;;) { 62 uint8 byte; 63 64 if (!GetByte(&byte) || byte == kLF) 65 return; 66 67 if (byte == kCR) { 68 if (GetByte(&byte) && byte != kLF) 69 UngetByte(); 70 71 return; 72 } 73 74 line->push_back(byte); 75 } 76 } 77 78 } // namespace media 79
