Add JPEG parser for JPEG decode acceleration

media/filters/jpeg_parser.h

+// Copyright 2015 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.
+//
+#ifndef MEDIA_FILTERS_JPEG_PARSER_H_
+#define MEDIA_FILTERS_JPEG_PARSER_H_
+
+#include <stddef.h>
+#include <stdint.h>
+#include "media/base/media_export.h"
+
+namespace media {
+
+const size_t kJpegMaxHuffmanTableNumBaseline = 2;
+const size_t kJpegMaxComponents = 4;
+const size_t kJpegMaxQuantizationTableNum = 4;
+
+// Parsing result of JPEG DHT marker.
+struct JpegHuffmanTable {
+  bool valid;
+  uint8_t code_length[16];
+  uint8_t code_value[256];
+};
+
+// Parsing result of JPEG DQT marker.
+struct JpegQuantizationTable {
+  bool valid;
+  uint8_t value[64];  // baseline only supports 8 bits quantization table
+};
+
+// Parsing result of a JPEG component.
+struct JpegComponent {
+  uint8_t id;
+  uint8_t horizontal_sampling_factor;
+  uint8_t vertical_sampling_factor;
+  uint8_t quantization_table_selector;
+};
+
+// Parsing result of a JPEG SOF marker.
+struct JpegFrameHeader {
+  uint16_t visible_width;
+  uint16_t visible_height;
+  uint8_t num_components;
+  JpegComponent components[kJpegMaxComponents];
+};
+
+// Parsing result of JPEG SOS marker.
+struct JpegScanHeader {
+  uint8_t num_components;
+  struct Component {
+    uint8_t component_selector;
+    uint8_t dc_selector;
+    uint8_t ac_selector;
+  } components[kJpegMaxComponents];
+};
+
+struct JpegParseResult {
+  JpegFrameHeader frame_header;
+  JpegHuffmanTable dc_table[kJpegMaxHuffmanTableNumBaseline];
+  JpegHuffmanTable ac_table[kJpegMaxHuffmanTableNumBaseline];
+  JpegQuantizationTable q_table[kJpegMaxQuantizationTableNum];
+  uint16_t restart_interval;
+  JpegScanHeader scan;
+  const char* data;
+  size_t data_size;
+};
+
+// Parses JPEG picture in |buffer| with |length|.  Returns true iff header is
+// valid and JPEG baseline sequential process is present. If parsed
+// successfully, |result| is the parsed result.
+// It's not a full featured JPEG parser implememtation. It only parses JPEG
+// baseline sequential process. For explanations of each struct and its
+// members, see JPEG specification at
+// http://www.w3.org/Graphics/JPEG/itu-t81.pdf.
+MEDIA_EXPORT bool ParseJpegPicture(const uint8_t* buffer,
+                                   size_t length,
+                                   JpegParseResult* result);
+
+}  // namespace media
+
+#endif  // MEDIA_FILTERS_JPEG_PARSER_H_