Media Source dispatches inband text tracks

media/webm/webm_webvtt_parser.cc

+// Copyright (c) 2013 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_webvtt_parser.h"
+
+namespace media {
+
+void WebMWebVTTParser::Parse(const uint8* payload, int payload_size,
+                             std::string* id,
+                             std::string* settings,
+                             std::string* content) {
+  WebMWebVTTParser parser(payload, payload_size);
+  parser.Parse(id, settings, content);
+}
+
+WebMWebVTTParser::WebMWebVTTParser(const uint8* payload, int payload_size)
+    : ptr_(payload),
+      ptr_end_(payload + payload_size) {
+}
+
+void WebMWebVTTParser::Parse(std::string* id,
+                             std::string* settings,
+                             std::string* content) {
+  ParseLine(id);
+  ParseLine(settings);
+  content->assign(ptr_, ptr_end_);
+}
+
+bool WebMWebVTTParser::GetByte(uint8* byte) {
+  if (ptr_ >= ptr_end_)
+    return false;  // indicates end-of-stream
+
+  *byte = *ptr_++;
+  return true;
+}
+
+void WebMWebVTTParser::UngetByte() {
+  --ptr_;
+}
+
+void WebMWebVTTParser::ParseLine(std::string* line) {
+  line->clear();
+
+  // Consume characters from the stream, until we reach end-of-line.
+
+  // The WebVTT spec states that lines may be terminated in any of the following
+  // three ways:
+  //  LF
+  //  CR
+  //  CR LF
+
+  // The spec is here:
+  //  http://wiki.webmproject.org/webm-metadata/temporal-metadata/webvtt-in-webm
+
+  enum {
+    kLF = '\x0A',
+    kCR = '\x0D'
+  };
+
+  for (;;) {
+    uint8 byte;
+
+    if (!GetByte(&byte) || byte == kLF)
+      return;
+
+    if (byte == kCR) {
+      if (GetByte(&byte) && byte != kLF)
+        UngetByte();
+
+      return;
+    }
+
+    line->push_back(byte);
+  }
+}
+
+}  // namespace media