1 /* libFLAC - Free Lossless Audio Codec
2 * Copyright (C) 2002,2003,2004,2005,2006 Josh Coalson
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
8 * - Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * - Neither the name of the Xiph.org Foundation nor the names of its
16 * contributors may be used to endorse or promote products derived from
17 * this software without specific prior written permission.
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
26 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
27 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
28 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
29 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 #include <string.h> /* for memcpy() */
37 #include "FLAC/assert.h"
38 #include "private/ogg_decoder_aspect.h"
39 #include "private/ogg_mapping.h"
44 #define max(x,y) ((x)>(y)?(x):(y))
46 /***********************************************************************
48 * Public class methods
50 ***********************************************************************/
52 FLAC__bool FLAC__ogg_decoder_aspect_init(FLAC__OggDecoderAspect *aspect)
54 /* we will determine the serial number later if necessary */
55 if(ogg_stream_init(&aspect->stream_state, aspect->serial_number) != 0)
58 if(ogg_sync_init(&aspect->sync_state) != 0)
61 aspect->version_major = ~(0u);
62 aspect->version_minor = ~(0u);
64 aspect->need_serial_number = aspect->use_first_serial_number;
66 aspect->end_of_stream = false;
67 aspect->have_working_page = false;
72 void FLAC__ogg_decoder_aspect_finish(FLAC__OggDecoderAspect *aspect)
74 (void)ogg_sync_clear(&aspect->sync_state);
75 (void)ogg_stream_clear(&aspect->stream_state);
78 void FLAC__ogg_decoder_aspect_set_serial_number(FLAC__OggDecoderAspect *aspect, long value)
80 aspect->use_first_serial_number = false;
81 aspect->serial_number = value;
84 void FLAC__ogg_decoder_aspect_set_defaults(FLAC__OggDecoderAspect *aspect)
86 aspect->use_first_serial_number = true;
89 void FLAC__ogg_decoder_aspect_flush(FLAC__OggDecoderAspect *aspect)
91 (void)ogg_stream_reset(&aspect->stream_state);
92 (void)ogg_sync_reset(&aspect->sync_state);
93 aspect->end_of_stream = false;
94 aspect->have_working_page = false;
97 void FLAC__ogg_decoder_aspect_reset(FLAC__OggDecoderAspect *aspect)
99 FLAC__ogg_decoder_aspect_flush(aspect);
101 if(aspect->use_first_serial_number)
102 aspect->need_serial_number = true;
105 FLAC__OggDecoderAspectReadStatus FLAC__ogg_decoder_aspect_read_callback_wrapper(FLAC__OggDecoderAspect *aspect, FLAC__byte buffer[], size_t *bytes, FLAC__OggDecoderAspectReadCallbackProxy read_callback, const FLAC__StreamDecoder *decoder, void *client_data)
107 static const size_t OGG_BYTES_CHUNK = 8192;
108 const size_t bytes_requested = *bytes;
111 * The FLAC decoding API uses pull-based reads, whereas Ogg decoding
112 * is push-based. In libFLAC, when you ask to decode a frame, the
113 * decoder will eventually call the read callback to supply some data,
114 * but how much it asks for depends on how much free space it has in
115 * its internal buffer. It does not try to grow its internal buffer
116 * to accomodate a whole frame because then the internal buffer size
117 * could not be limited, which is necessary in embedded applications.
119 * Ogg however grows its internal buffer until a whole page is present;
120 * only then can you get decoded data out. So we can't just ask for
121 * the same number of bytes from Ogg, then pass what's decoded down to
122 * libFLAC. If what libFLAC is asking for will not contain a whole
123 * page, then we will get no data from ogg_sync_pageout(), and at the
124 * same time cannot just read more data from the client for the purpose
125 * of getting a whole decoded page because the decoded size might be
126 * larger than libFLAC's internal buffer.
128 * Instead, whenever this read callback wrapper is called, we will
129 * continually request data from the client until we have at least one
130 * page, and manage pages internally so that we can send pieces of
131 * pages down to libFLAC in such a way that we obey its size
132 * requirement. To limit the amount of callbacks, we will always try
133 * to read in enough pages to return the full number of bytes
137 while (*bytes < bytes_requested && !aspect->end_of_stream) {
138 if (aspect->have_working_page) {
139 if (aspect->have_working_packet) {
140 size_t n = bytes_requested - *bytes;
141 if ((size_t)aspect->working_packet.bytes <= n) {
142 /* the rest of the packet will fit in the buffer */
143 n = aspect->working_packet.bytes;
144 memcpy(buffer, aspect->working_packet.packet, n);
147 aspect->have_working_packet = false;
150 /* only n bytes of the packet will fit in the buffer */
151 memcpy(buffer, aspect->working_packet.packet, n);
154 aspect->working_packet.packet += n;
155 aspect->working_packet.bytes -= n;
159 /* try and get another packet */
160 const int ret = ogg_stream_packetout(&aspect->stream_state, &aspect->working_packet);
162 aspect->have_working_packet = true;
163 /* if it is the first header packet, check for magic and a supported Ogg FLAC mapping version */
164 if (aspect->working_packet.bytes > 0 && aspect->working_packet.packet[0] == FLAC__OGG_MAPPING_FIRST_HEADER_PACKET_TYPE) {
165 const FLAC__byte *b = aspect->working_packet.packet;
166 const unsigned header_length =
167 FLAC__OGG_MAPPING_PACKET_TYPE_LENGTH +
168 FLAC__OGG_MAPPING_MAGIC_LENGTH +
169 FLAC__OGG_MAPPING_VERSION_MAJOR_LENGTH +
170 FLAC__OGG_MAPPING_VERSION_MINOR_LENGTH +
171 FLAC__OGG_MAPPING_NUM_HEADERS_LENGTH;
172 if (aspect->working_packet.bytes < (long)header_length)
173 return FLAC__OGG_DECODER_ASPECT_READ_STATUS_NOT_FLAC;
174 b += FLAC__OGG_MAPPING_PACKET_TYPE_LENGTH;
175 if (memcmp(b, FLAC__OGG_MAPPING_MAGIC, FLAC__OGG_MAPPING_MAGIC_LENGTH))
176 return FLAC__OGG_DECODER_ASPECT_READ_STATUS_NOT_FLAC;
177 b += FLAC__OGG_MAPPING_MAGIC_LENGTH;
178 aspect->version_major = (unsigned)(*b);
179 b += FLAC__OGG_MAPPING_VERSION_MAJOR_LENGTH;
180 aspect->version_minor = (unsigned)(*b);
181 if (aspect->version_major != 1)
182 return FLAC__OGG_DECODER_ASPECT_READ_STATUS_UNSUPPORTED_MAPPING_VERSION;
183 aspect->working_packet.packet += header_length;
184 aspect->working_packet.bytes -= header_length;
188 aspect->have_working_page = false;
191 /* lost sync, we'll leave the working page for the next call */
192 return FLAC__OGG_DECODER_ASPECT_READ_STATUS_LOST_SYNC;
197 /* try and get another page */
198 const int ret = ogg_sync_pageout(&aspect->sync_state, &aspect->working_page);
200 /* got a page, grab the serial number if necessary */
201 if(aspect->need_serial_number) {
202 aspect->stream_state.serialno = aspect->serial_number = ogg_page_serialno(&aspect->working_page);
203 aspect->need_serial_number = false;
205 if(ogg_stream_pagein(&aspect->stream_state, &aspect->working_page) == 0) {
206 aspect->have_working_page = true;
207 aspect->have_working_packet = false;
209 /* else do nothing, could be a page from another stream */
213 const size_t ogg_bytes_to_read = max(bytes_requested - *bytes, OGG_BYTES_CHUNK);
214 char *oggbuf = ogg_sync_buffer(&aspect->sync_state, ogg_bytes_to_read);
217 return FLAC__OGG_DECODER_ASPECT_READ_STATUS_MEMORY_ALLOCATION_ERROR;
220 size_t ogg_bytes_read = ogg_bytes_to_read;
222 switch(read_callback(decoder, (FLAC__byte*)oggbuf, &ogg_bytes_read, client_data)) {
223 case FLAC__OGG_DECODER_ASPECT_READ_STATUS_OK:
225 case FLAC__OGG_DECODER_ASPECT_READ_STATUS_END_OF_STREAM:
226 aspect->end_of_stream = true;
228 case FLAC__OGG_DECODER_ASPECT_READ_STATUS_ABORT:
229 return FLAC__OGG_DECODER_ASPECT_READ_STATUS_ABORT;
234 if(ogg_sync_wrote(&aspect->sync_state, ogg_bytes_read) < 0) {
235 /* double protection; this will happen if the read callback returns more bytes than the max requested, which would overflow Ogg's internal buffer */
237 return FLAC__OGG_DECODER_ASPECT_READ_STATUS_ERROR;
242 /* lost sync, bail out */
243 return FLAC__OGG_DECODER_ASPECT_READ_STATUS_LOST_SYNC;
248 if (aspect->end_of_stream && *bytes == 0) {
249 return FLAC__OGG_DECODER_ASPECT_READ_STATUS_END_OF_STREAM;
252 return FLAC__OGG_DECODER_ASPECT_READ_STATUS_OK;