+/*****************************************************************************
+ * flac.c: flac packetizer module.
+ *****************************************************************************
+ * Copyright (C) 1999-2001 the VideoLAN team
+ * $Id$
+ *
+ * Authors: Gildas Bazin <gbazin@videolan.org>
+ * Sigmund Augdal Helberg <dnumgis@videolan.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Preamble
+ *****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <vlc_common.h>
+#include <vlc_plugin.h>
+#include <vlc_codec.h>
+
+#include <vlc_block_helper.h>
+#include <vlc_bits.h>
+
+/*****************************************************************************
+ * Module descriptor
+ *****************************************************************************/
+static int Open ( vlc_object_t * );
+static void Close( vlc_object_t * );
+
+vlc_module_begin()
+ set_category( CAT_SOUT )
+ set_subcategory( SUBCAT_SOUT_PACKETIZER )
+ set_description( N_("Flac audio packetizer") )
+ set_capability( "packetizer", 50 )
+ set_callbacks( Open, Close )
+vlc_module_end()
+
+/*****************************************************************************
+ * decoder_sys_t : FLAC decoder descriptor
+ *****************************************************************************/
+#define MAX_FLAC_HEADER_SIZE 16
+struct decoder_sys_t
+{
+ /*
+ * Input properties
+ */
+ int i_state;
+
+ block_bytestream_t bytestream;
+
+ /*
+ * FLAC properties
+ */
+ struct
+ {
+ unsigned min_blocksize, max_blocksize;
+ unsigned min_framesize, max_framesize;
+ unsigned sample_rate;
+ unsigned channels;
+ unsigned bits_per_sample;
+
+ } stream_info;
+ bool b_stream_info;
+
+ /*
+ * Common properties
+ */
+ date_t end_date;
+ mtime_t i_pts;
+
+ int i_frame_size, i_frame_length, i_bits_per_sample;
+ unsigned int i_rate, i_channels;
+};
+
+enum
+{
+ STATE_NOSYNC,
+ STATE_SYNC,
+ STATE_HEADER,
+ STATE_NEXT_SYNC,
+ STATE_GET_DATA,
+ STATE_SEND_DATA
+};
+
+/*****************************************************************************
+ * Local prototypes
+ *****************************************************************************/
+static block_t *Packetize( decoder_t *, block_t ** );
+
+static int SyncInfo( decoder_t *, uint8_t *, unsigned int *,
+ unsigned int *,int * );
+
+static uint64_t read_utf8( const uint8_t *p_buf, int *pi_read );
+static uint8_t flac_crc8( const uint8_t *data, unsigned len );
+
+static int Open( vlc_object_t *p_this )
+{
+ decoder_t *p_dec = (decoder_t*)p_this;
+ decoder_sys_t *p_sys;
+
+ if( p_dec->fmt_in.i_codec != VLC_CODEC_FLAC )
+ return VLC_EGENERIC;
+
+ /* */
+ p_dec->p_sys = p_sys = malloc(sizeof(*p_sys));
+ if( !p_sys )
+ return VLC_ENOMEM;
+
+ date_Set( &p_sys->end_date, 0 );
+ p_sys->i_state = STATE_NOSYNC;
+ p_sys->b_stream_info = false;
+ p_sys->i_pts = VLC_TS_INVALID;
+ p_sys->bytestream = block_BytestreamInit();
+
+ /* */
+ es_format_Copy( &p_dec->fmt_out, &p_dec->fmt_in );
+ p_dec->fmt_out.i_cat = AUDIO_ES;
+ p_dec->fmt_out.i_codec = VLC_CODEC_FLAC;
+
+ /* */
+ p_dec->pf_decode_audio = NULL;
+ p_dec->pf_packetize = Packetize;
+
+ return VLC_SUCCESS;
+}
+
+static void Close( vlc_object_t *p_this )
+{
+ decoder_t *p_dec = (decoder_t *)p_this;
+ decoder_sys_t *p_sys = p_dec->p_sys;
+
+ free( p_sys );
+}
+
+/*****************************************************************************
+ * ProcessHeader: process Flac header.
+ *****************************************************************************/
+static void ProcessHeader( decoder_t *p_dec )
+{
+ decoder_sys_t *p_sys = p_dec->p_sys;
+
+ bs_t bs;
+
+ if( !p_dec->fmt_in.i_extra )
+ return;
+
+ bs_init( &bs, p_dec->fmt_in.p_extra, p_dec->fmt_in.i_extra );
+
+ p_sys->stream_info.min_blocksize = bs_read( &bs, 16 );
+ p_sys->stream_info.max_blocksize = bs_read( &bs, 16 );
+
+ p_sys->stream_info.min_framesize = bs_read( &bs, 24 );
+ p_sys->stream_info.max_framesize = bs_read( &bs, 24 );
+
+ p_sys->stream_info.sample_rate = bs_read( &bs, 20 );
+ p_sys->stream_info.channels = bs_read( &bs, 3 ) + 1;
+ p_sys->stream_info.bits_per_sample = bs_read( &bs, 5 ) + 1;
+
+ p_sys->b_stream_info = true;
+
+ p_dec->fmt_out.i_extra = p_dec->fmt_in.i_extra;
+ p_dec->fmt_out.p_extra = xrealloc( p_dec->fmt_out.p_extra,
+ p_dec->fmt_out.i_extra );
+ memcpy( p_dec->fmt_out.p_extra,
+ p_dec->fmt_in.p_extra, p_dec->fmt_out.i_extra );
+}
+
+/* */
+static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
+{
+ decoder_sys_t *p_sys = p_dec->p_sys;
+ uint8_t p_header[MAX_FLAC_HEADER_SIZE];
+ block_t *p_sout_block;
+
+ if( !pp_block || !*pp_block ) return NULL;
+
+ if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
+ {
+ if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
+ {
+ p_sys->i_state = STATE_NOSYNC;
+ block_BytestreamEmpty( &p_sys->bytestream );
+ }
+ date_Set( &p_sys->end_date, 0 );
+ block_Release( *pp_block );
+ return NULL;
+ }
+
+ if( !p_sys->b_stream_info )
+ ProcessHeader( p_dec );
+
+ if( p_sys->stream_info.channels > 6 )
+ {
+ msg_Err( p_dec, "This stream uses too many audio channels" );
+ return NULL;
+ }
+
+ if( !date_Get( &p_sys->end_date ) && (*pp_block)->i_pts <= VLC_TS_INVALID )
+ {
+ /* We've just started the stream, wait for the first PTS. */
+ block_Release( *pp_block );
+ return NULL;
+ }
+ else if( !date_Get( &p_sys->end_date ) )
+ {
+ /* The first PTS is as good as anything else. */
+ p_sys->i_rate = p_dec->fmt_out.audio.i_rate;
+ date_Init( &p_sys->end_date, p_sys->i_rate, 1 );
+ date_Set( &p_sys->end_date, (*pp_block)->i_pts );
+ }
+
+ block_BytestreamPush( &p_sys->bytestream, *pp_block );
+
+ while( 1 )
+ {
+ switch( p_sys->i_state )
+ {
+ case STATE_NOSYNC:
+ while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
+ == VLC_SUCCESS )
+ {
+ if( p_header[0] == 0xFF && p_header[1] == 0xF8 )
+ {
+ p_sys->i_state = STATE_SYNC;
+ break;
+ }
+ block_SkipByte( &p_sys->bytestream );
+ }
+ if( p_sys->i_state != STATE_SYNC )
+ {
+ block_BytestreamFlush( &p_sys->bytestream );
+
+ /* Need more data */
+ return NULL;
+ }
+
+ case STATE_SYNC:
+ /* New frame, set the Presentation Time Stamp */
+ p_sys->i_pts = p_sys->bytestream.p_block->i_pts;
+ if( p_sys->i_pts > VLC_TS_INVALID &&
+ p_sys->i_pts != date_Get( &p_sys->end_date ) )
+ {
+ date_Set( &p_sys->end_date, p_sys->i_pts );
+ }
+ p_sys->i_state = STATE_HEADER;
+
+ case STATE_HEADER:
+ /* Get FLAC frame header (MAX_FLAC_HEADER_SIZE bytes) */
+ if( block_PeekBytes( &p_sys->bytestream, p_header,
+ MAX_FLAC_HEADER_SIZE ) != VLC_SUCCESS )
+ {
+ /* Need more data */
+ return NULL;
+ }
+
+ /* Check if frame is valid and get frame info */
+ p_sys->i_frame_length = SyncInfo( p_dec, p_header,
+ &p_sys->i_channels,
+ &p_sys->i_rate,
+ &p_sys->i_bits_per_sample );
+ if( !p_sys->i_frame_length )
+ {
+ msg_Dbg( p_dec, "emulated sync word" );
+ block_SkipByte( &p_sys->bytestream );
+ p_sys->i_state = STATE_NOSYNC;
+ break;
+ }
+ if( p_sys->i_rate != p_dec->fmt_out.audio.i_rate )
+ {
+ p_dec->fmt_out.audio.i_rate = p_sys->i_rate;
+ date_Init( &p_sys->end_date, p_sys->i_rate, 1 );
+ date_Set( &p_sys->end_date, p_sys->i_pts );
+ }
+ p_sys->i_state = STATE_NEXT_SYNC;
+ p_sys->i_frame_size = 1;
+
+ case STATE_NEXT_SYNC:
+ /* TODO: If pp_block == NULL, flush the buffer without checking the
+ * next sync word */
+
+ /* Check if next expected frame contains the sync word */
+ while( block_PeekOffsetBytes( &p_sys->bytestream,
+ p_sys->i_frame_size, p_header,
+ MAX_FLAC_HEADER_SIZE )
+ == VLC_SUCCESS )
+ {
+ if( p_header[0] == 0xFF && p_header[1] == 0xF8 )
+ {
+ /* Check if frame is valid and get frame info */
+ int i_frame_length =
+ SyncInfo( p_dec, p_header,
+ &p_sys->i_channels,
+ &p_sys->i_rate,
+ &p_sys->i_bits_per_sample );
+
+ if( i_frame_length )
+ {
+ p_sys->i_state = STATE_SEND_DATA;
+ break;
+ }
+ }
+ p_sys->i_frame_size++;
+ }
+
+ if( p_sys->i_state != STATE_SEND_DATA )
+ {
+ /* Need more data */
+ return NULL;
+ }
+
+ case STATE_SEND_DATA:
+ p_sout_block = block_New( p_dec, p_sys->i_frame_size );
+
+ /* Copy the whole frame into the buffer. When we reach this point
+ * we already know we have enough data available. */
+ block_GetBytes( &p_sys->bytestream, p_sout_block->p_buffer,
+ p_sys->i_frame_size );
+
+ /* Make sure we don't reuse the same pts twice */
+ if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts )
+ p_sys->i_pts = p_sys->bytestream.p_block->i_pts = VLC_TS_INVALID;
+
+ /* So p_block doesn't get re-added several times */
+ *pp_block = block_BytestreamPop( &p_sys->bytestream );
+
+ p_sys->i_state = STATE_NOSYNC;
+
+ /* Date management */
+ p_sout_block->i_pts =
+ p_sout_block->i_dts = date_Get( &p_sys->end_date );
+ date_Increment( &p_sys->end_date, p_sys->i_frame_length );
+ p_sout_block->i_length =
+ date_Get( &p_sys->end_date ) - p_sout_block->i_pts;
+
+ return p_sout_block;
+ }
+ }
+
+ return NULL;
+}
+
+/*****************************************************************************
+ * SyncInfo: parse FLAC sync info
+ *****************************************************************************/
+static int SyncInfo( decoder_t *p_dec, uint8_t *p_buf,
+ unsigned int * pi_channels,
+ unsigned int * pi_sample_rate,
+ int * pi_bits_per_sample )
+{
+ decoder_sys_t *p_sys = p_dec->p_sys;
+ int i_header, i_temp, i_read;
+ unsigned i_blocksize = 0;
+ int i_blocksize_hint = 0, i_sample_rate_hint = 0;
+ uint64_t i_sample_number = 0;
+
+ bool b_variable_blocksize = ( p_sys->b_stream_info &&
+ p_sys->stream_info.min_blocksize != p_sys->stream_info.max_blocksize );
+ bool b_fixed_blocksize = ( p_sys->b_stream_info &&
+ p_sys->stream_info.min_blocksize == p_sys->stream_info.max_blocksize );
+
+ /* Check syncword */
+ if( p_buf[0] != 0xFF || p_buf[1] != 0xF8 ) return 0;
+
+ /* Check there is no emulated sync code in the rest of the header */
+ if( p_buf[2] == 0xff || p_buf[3] == 0xFF ) return 0;
+
+ /* Find blocksize (framelength) */
+ switch( i_temp = p_buf[2] >> 4 )
+ {
+ case 0:
+ if( b_fixed_blocksize )
+ i_blocksize = p_sys->stream_info.min_blocksize;
+ else return 0; /* We can't do anything with this */
+ break;
+
+ case 1:
+ i_blocksize = 192;
+ break;
+
+ case 2:
+ case 3:
+ case 4:
+ case 5:
+ i_blocksize = 576 << (i_temp - 2);
+ break;
+
+ case 6:
+ case 7:
+ i_blocksize_hint = i_temp;
+ break;
+
+ case 8:
+ case 9:
+ case 10:
+ case 11:
+ case 12:
+ case 13:
+ case 14:
+ case 15:
+ i_blocksize = 256 << (i_temp - 8);
+ break;
+ }
+
+ /* Find samplerate */
+ switch( i_temp = p_buf[2] & 0x0f )
+ {
+ case 0:
+ if( p_sys->b_stream_info )
+ *pi_sample_rate = p_sys->stream_info.sample_rate;
+ else return 0; /* We can't do anything with this */
+ break;
+
+ case 1:
+ *pi_sample_rate = 88200;
+ break;
+
+ case 2:
+ *pi_sample_rate = 176400;
+ break;
+
+ case 3:
+ *pi_sample_rate = 192000;
+ break;
+
+ case 4:
+ *pi_sample_rate = 8000;
+ break;
+
+ case 5:
+ *pi_sample_rate = 16000;
+ break;
+
+ case 6:
+ *pi_sample_rate = 22050;
+ break;
+
+ case 7:
+ *pi_sample_rate = 24000;
+ break;
+
+ case 8:
+ *pi_sample_rate = 32000;
+ break;
+
+ case 9:
+ *pi_sample_rate = 44100;
+ break;
+
+ case 10:
+ *pi_sample_rate = 48000;
+ break;
+
+ case 11:
+ *pi_sample_rate = 96000;
+ break;
+
+ case 12:
+ case 13:
+ case 14:
+ i_sample_rate_hint = i_temp;
+ break;
+
+ case 15:
+ return 0;
+ }
+
+ /* Find channels */
+ i_temp = (unsigned)(p_buf[3] >> 4);
+ if( i_temp & 8 )
+ {
+ if( ( i_temp & 7 ) >= 3 )
+ return 0;
+ *pi_channels = 2;
+ }
+ else
+ {
+ *pi_channels = i_temp + 1;
+ }
+
+ /* Find bits per sample */
+ switch( i_temp = (unsigned)(p_buf[3] & 0x0e) >> 1 )
+ {
+ case 0:
+ if( p_sys->b_stream_info )
+ *pi_bits_per_sample = p_sys->stream_info.bits_per_sample;
+ else
+ return 0;
+ break;
+
+ case 1:
+ *pi_bits_per_sample = 8;
+ break;
+
+ case 2:
+ *pi_bits_per_sample = 12;
+ break;
+
+ case 4:
+ *pi_bits_per_sample = 16;
+ break;
+
+ case 5:
+ *pi_bits_per_sample = 20;
+ break;
+
+ case 6:
+ *pi_bits_per_sample = 24;
+ break;
+
+ case 3:
+ case 7:
+ return 0;
+ break;
+ }
+
+ /* Zero padding bit */
+ if( p_buf[3] & 0x01 ) return 0;
+
+ /* End of fixed size header */
+ i_header = 4;
+
+ /* Find Sample/Frame number */
+ if( i_blocksize_hint && b_variable_blocksize )
+ {
+ i_sample_number = read_utf8( &p_buf[i_header++], &i_read );
+ if( i_sample_number == INT64_C(0xffffffffffffffff) ) return 0;
+ }
+ else
+ {
+ i_sample_number = read_utf8( &p_buf[i_header++], &i_read );
+ if( i_sample_number == INT64_C(0xffffffffffffffff) ) return 0;
+
+ if( p_sys->b_stream_info )
+ i_sample_number *= p_sys->stream_info.min_blocksize;
+ }
+
+ i_header += i_read;
+
+ /* Read blocksize */
+ if( i_blocksize_hint )
+ {
+ int i_val1 = p_buf[i_header++];
+ if( i_blocksize_hint == 7 )
+ {
+ int i_val2 = p_buf[i_header++];
+ i_val1 = (i_val1 << 8) | i_val2;
+ }
+ i_blocksize = i_val1 + 1;
+ }
+
+ /* Read sample rate */
+ if( i_sample_rate_hint )
+ {
+ int i_val1 = p_buf[i_header++];
+ if( i_sample_rate_hint != 12 )
+ {
+ int i_val2 = p_buf[i_header++];
+ i_val1 = (i_val1 << 8) | i_val2;
+ }
+ if( i_sample_rate_hint == 12 ) *pi_sample_rate = i_val1 * 1000;
+ else if( i_sample_rate_hint == 13 ) *pi_sample_rate = i_val1;
+ else *pi_sample_rate = i_val1 * 10;
+ }
+
+ /* Check the CRC-8 byte */
+ if( flac_crc8( p_buf, i_header ) != p_buf[i_header] )
+ {
+ return 0;
+ }
+
+ /* Sanity check using stream info header when possible */
+ if( p_sys->b_stream_info )
+ {
+ if( i_blocksize < p_sys->stream_info.min_blocksize ||
+ i_blocksize > p_sys->stream_info.max_blocksize )
+ return 0;
+ }
+ return i_blocksize;
+}
+
+/* Will return 0xffffffffffffffff for an invalid utf-8 sequence */
+static uint64_t read_utf8( const uint8_t *p_buf, int *pi_read )
+{
+ uint64_t i_result = 0;
+ unsigned i, j;
+
+ if( !(p_buf[0] & 0x80) ) /* 0xxxxxxx */
+ {
+ i_result = p_buf[0];
+ i = 0;
+ }
+ else if( p_buf[0] & 0xC0 && !(p_buf[0] & 0x20) ) /* 110xxxxx */
+ {
+ i_result = p_buf[0] & 0x1F;
+ i = 1;
+ }
+ else if( p_buf[0] & 0xE0 && !(p_buf[0] & 0x10) ) /* 1110xxxx */
+ {
+ i_result = p_buf[0] & 0x0F;
+ i = 2;
+ }
+ else if( p_buf[0] & 0xF0 && !(p_buf[0] & 0x08) ) /* 11110xxx */
+ {
+ i_result = p_buf[0] & 0x07;
+ i = 3;
+ }
+ else if( p_buf[0] & 0xF8 && !(p_buf[0] & 0x04) ) /* 111110xx */
+ {
+ i_result = p_buf[0] & 0x03;
+ i = 4;
+ }
+ else if( p_buf[0] & 0xFC && !(p_buf[0] & 0x02) ) /* 1111110x */
+ {
+ i_result = p_buf[0] & 0x01;
+ i = 5;
+ }
+ else if( p_buf[0] & 0xFE && !(p_buf[0] & 0x01) ) /* 11111110 */
+ {
+ i_result = 0;
+ i = 6;
+ }
+ else {
+ return INT64_C(0xffffffffffffffff);
+ }
+
+ for( j = 1; j <= i; j++ )
+ {
+ if( !(p_buf[j] & 0x80) || (p_buf[j] & 0x40) ) /* 10xxxxxx */
+ {
+ return INT64_C(0xffffffffffffffff);
+ }
+ i_result <<= 6;
+ i_result |= (p_buf[j] & 0x3F);
+ }
+
+ *pi_read = i;
+ return i_result;
+}
+
+/* CRC-8, poly = x^8 + x^2 + x^1 + x^0, init = 0 */
+static const uint8_t flac_crc8_table[256] = {
+ 0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15,
+ 0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D,
+ 0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65,
+ 0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D,
+ 0xE0, 0xE7, 0xEE, 0xE9, 0xFC, 0xFB, 0xF2, 0xF5,
+ 0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD,
+ 0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85,
+ 0xA8, 0xAF, 0xA6, 0xA1, 0xB4, 0xB3, 0xBA, 0xBD,
+ 0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2,
+ 0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA,
+ 0xB7, 0xB0, 0xB9, 0xBE, 0xAB, 0xAC, 0xA5, 0xA2,
+ 0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A,
+ 0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32,
+ 0x1F, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0D, 0x0A,
+ 0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42,
+ 0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A,
+ 0x89, 0x8E, 0x87, 0x80, 0x95, 0x92, 0x9B, 0x9C,
+ 0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4,
+ 0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC,
+ 0xC1, 0xC6, 0xCF, 0xC8, 0xDD, 0xDA, 0xD3, 0xD4,
+ 0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C,
+ 0x51, 0x56, 0x5F, 0x58, 0x4D, 0x4A, 0x43, 0x44,
+ 0x19, 0x1E, 0x17, 0x10, 0x05, 0x02, 0x0B, 0x0C,
+ 0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A, 0x33, 0x34,
+ 0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B,
+ 0x76, 0x71, 0x78, 0x7F, 0x6A, 0x6D, 0x64, 0x63,
+ 0x3E, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B,
+ 0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13,
+ 0xAE, 0xA9, 0xA0, 0xA7, 0xB2, 0xB5, 0xBC, 0xBB,
+ 0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83,
+ 0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB,
+ 0xE6, 0xE1, 0xE8, 0xEF, 0xFA, 0xFD, 0xF4, 0xF3
+};
+
+static uint8_t flac_crc8( const uint8_t *data, unsigned len )
+{
+ uint8_t crc = 0;
+
+ while(len--)
+ crc = flac_crc8_table[crc ^ *data++];
+
+ return crc;
+}
+