kolibrios/programs/media/ac97snd/trunk/mpg/readers.c
Sergey Semyonov (Serge) a646a65def bugfix
git-svn-id: svn://kolibrios.org@286 a494cfbc-eb01-0410-851d-a64ba20cac60
2007-01-20 08:51:41 +00:00

889 lines
26 KiB
C

#include "mpg123.h"
#include "..\kolibri.h"
#define MAXFRAMESIZE 3456
static int fsizeold=0,ssize;
static unsigned char bsspace[2][MAXFRAMESIZE+512]; /* MAXFRAMESIZE */
static unsigned char *bsbuf=bsspace[1],*bsbufold;
static int bsnum=0;
static unsigned long oldhead = 0;
unsigned long firsthead=0;
struct bitstream_info bsi;
int tabsel_123[2][3][16] = {
{ {0,32,64,96,128,160,192,224,256,288,320,352,384,416,448,},
{0,32,48,56, 64, 80, 96,112,128,160,192,224,256,320,384,},
{0,32,40,48, 56, 64, 80, 96,112,128,160,192,224,256,320,} },
{ {0,32,48,56,64,80,96,112,128,144,160,176,192,224,256,},
{0,8,16,24,32,40,48,56,64,80,96,112,128,144,160,},
{0,8,16,24,32,40,48,56,64,80,96,112,128,144,160,} }
};
int freqs[9] = { 44100, 48000, 32000, 22050, 24000, 16000 , 11025 , 12000 , 8000 };
int stream_head_read(struct reader *rd,unsigned long *newhead);
int stream_read_raw(struct reader *rd,unsigned char *buf, int size);
void set_synth_functions(struct frame *fr)
{
#ifdef USE_3DNOW
static func_dct36 funcs_dct36[2] = {dct36 , dct36_3dnow};
#endif
fr->synth = synth_1to1;
fr->synth_mono = synth_1to1_mono2stereo;;
/* TODO: make autodetection for _all_ x86 optimizations (maybe just for i586+ and keep separate 486 build?) */
#ifdef USE_3DNOW
/* check cpuflags bit 31 (3DNow!) and 23 (MMX) */
if((param.stat_3dnow < 2) &&
((param.stat_3dnow == 1) ||
(getcpuflags() & 0x80800000) == 0x80800000))
{
fr->synth = funcs[2][ds]; /* 3DNow! optimized synth_1to1() */
fr->dct36 = funcs_dct36[1]; /* 3DNow! optimized dct36() */
}
else
{
fr->dct36 = funcs_dct36[0];
}
#endif
}
int __stdcall create_reader(struct reader *rd,byte *buffer, int buffsize)
{ rd->head_read = stream_head_read;
rd->read_frame_body = stream_read_raw;
rd->buffer = buffer;
rd->stream = buffer;
rd->strpos = 0;
rd->strremain = 0;
rd->filepos = 0;
return 1;
};
int __stdcall init_reader(struct reader *rd, char *file)
{ FILEINFO fileinfo;
int retval;
int bytes;
rd->hFile = file;
get_fileinfo(file, &fileinfo);
rd->filelen = fileinfo.size;
rd->strpos = 0;
retval=read_file (file,rd->buffer,0,0x10000,&bytes);
if (retval) return 0;
rd->strremain = bytes;
rd->filepos = bytes;
return 1;
};
static int fill_reader(struct reader *rd)
{ int retval;
int bytes;
mem_cpy(rd->buffer,rd->stream,rd->strremain);
rd->stream = rd->buffer;
retval=read_file (rd->hFile,rd->buffer+rd->strremain,rd->filepos,
0x10000-rd->strremain,&bytes);
if (retval) return 0;
if(!bytes) return 0;
rd->strremain+=bytes;
rd->filepos+=bytes;
rd->strpos = 0;
return 1;
};
int __stdcall set_reader(struct reader *rd, unsigned int filepos)
{ int retval;
unsigned int bytes;
retval=read_file (rd->hFile,rd->buffer,filepos,0x10000,&bytes);
if (retval) return 0;
rd->stream = rd->buffer;
rd->strremain=bytes;
rd->filepos=filepos+bytes;
rd->strpos = 0;
fsizeold=0;
firsthead=0;
bsbufold = 0;
bsbuf = bsspace[1];
bsnum = 0;
ssize=0;
oldhead=0;
memset(bsspace,0,sizeof(bsspace));
return 1;
};
static int stream_head_read(struct reader *rd,unsigned long *newhead)
{
if(rd->strremain < 4)
if( !fill_reader(rd))
return 0;
*newhead = (rd->stream[0]<<24)|(rd->stream[1] << 16)|
(rd->stream[2] << 8)| rd->stream[3];
rd->strpos+=4;
rd->stream+=4;
rd->strremain-=4;
return TRUE;
};
int stream_read_raw(struct reader *rd,unsigned char *buf, int size)
{
if(rd->strremain < size)
if( !fill_reader(rd))
return 0;
mem_cpy(buf,rd->stream,size);
rd->strpos+=size;
rd->stream+=size;
rd->strremain-=size;
return 1;
};
void set_pointer(long backstep)
{
bsi.wordpointer = bsbuf + ssize - backstep;
if (backstep)
mem_cpy(bsi.wordpointer,bsbufold+fsizeold-backstep,backstep);
bsi.bitindex = 0;
}
int head_check(unsigned long head)
{ if
(
/* first 11 bits are set to 1 for frame sync */
((head & 0xffe00000) != 0xffe00000)
||
/* layer: 01,10,11 is 1,2,3; 00 is reserved */
(!((head>>17)&3))
||
/* 1111 means bad bitrate */
(((head>>12)&0xf) == 0xf)
||
/* 0000 means free format... */
(((head>>12)&0xf) == 0x0)
||
/* sampling freq: 11 is reserved */
(((head>>10)&0x3) == 0x3 )
/* here used to be a mpeg 2.5 check... re-enabled 2.5 decoding due to lack of evidence that it is really not good */
)
{
return FALSE;
}
/* if no check failed, the header is valid (hopefully)*/
else
{
return TRUE;
}
}
int __stdcall decode_header(struct frame *fr,unsigned long newhead)
{
if(!head_check(newhead))
return 0;
if( newhead & (1<<20) )
{ fr->lsf = (newhead & (1<<19)) ? 0x0 : 0x1;
fr->mpeg25 = 0;
}
else
{ fr->lsf = 1;
fr->mpeg25 = 1;
};
fr->lay = 4-((newhead>>17)&3);
if(fr->mpeg25)
fr->sampling_frequency = 6 + ((newhead>>10)&0x3);
else
fr->sampling_frequency = ((newhead>>10)&0x3) + (fr->lsf*3);
fr->error_protection = ((newhead>>16)&0x1)^0x1;
fr->bitrate_index = ((newhead>>12)&0xf);
fr->padding = ((newhead>>9)&0x1);
fr->extension = ((newhead>>8)&0x1);
fr->mode = ((newhead>>6)&0x3);
fr->mode_ext = ((newhead>>4)&0x3);
fr->copyright = ((newhead>>3)&0x1);
fr->original = ((newhead>>2)&0x1);
fr->emphasis = newhead & 0x3;
fr->stereo = (fr->mode == MPG_MD_MONO) ? 1 : 2;
oldhead = newhead;
if(!fr->bitrate_index)
return (0);
switch(fr->lay)
{ case 1:
fr->do_layer = do_layer1;
#ifdef VARMODESUPPORT
if (varmode) {
error("Sorry, layer-1 not supported in varmode.");
return (0);
}
#endif
fr->framesize = (long) tabsel_123[fr->lsf][0][fr->bitrate_index] * 12000;
fr->framesize /= freqs[fr->sampling_frequency];
fr->framesize = ((fr->framesize+fr->padding)<<2)-4;
break;
case 2:
fr->do_layer = do_layer2;
#ifdef VARMODESUPPORT
if (varmode) {
error("Sorry, layer-2 not supported in varmode.");
return (0);
}
#endif
fr->framesize = (long) tabsel_123[fr->lsf][1][fr->bitrate_index] * 144000;
fr->framesize /= freqs[fr->sampling_frequency];
fr->framesize += fr->padding - 4;
break;
case 3:
fr->do_layer = do_layer3;
if(fr->lsf)
ssize = (fr->stereo == 1) ? 9 : 17;
else
ssize = (fr->stereo == 1) ? 17 : 32;
if(fr->error_protection)
ssize += 2;
fr->framesize = (long) tabsel_123[fr->lsf][2][fr->bitrate_index] * 144000;
fr->framesize /= freqs[fr->sampling_frequency]<<(fr->lsf);
fr->framesize = fr->framesize + fr->padding - 4;
break;
default:
return (0);
}
if (fr->framesize > MAXFRAMESIZE)
return (0);
return 1;
}
int read_frame(struct reader *rd, struct frame *fr)
{ unsigned long newhead;
static unsigned char ssave[34];
//off_t framepos;
fsizeold=fr->framesize; /* for Layer3 */
read_again:
if(!rd->head_read(rd,&newhead))
return FALSE;
if(!decode_header(fr,newhead))
{ rd->strpos-=3;
rd->stream-=3;
rd->strremain+=3;
goto read_again;
};
#if 0
if(1 || oldhead != newhead || !oldhead)
{
init_resync:
#ifdef SKIP_JUNK
/* watch out for junk/tags on beginning of stream by invalid header */
if(!firsthead && !head_check(newhead) && !free_format_header(newhead)) {
int i;
/* check for id3v2; first three bytes (of 4) are "ID3" */
if((newhead & (unsigned long) 0xffffff00) == (unsigned long) 0x49443300)
{
int id3length = 0;
id3length = parse_new_id3(newhead, rd);
goto read_again;
}
else if(param.verbose > 1) fprintf(stderr,"Note: Junk at the beginning (0x%08lx)\n",newhead);
/* I even saw RIFF headers at the beginning of MPEG streams ;( */
if(newhead == ('R'<<24)+('I'<<16)+('F'<<8)+'F') {
if(param.verbose > 1) fprintf(stderr, "Note: Looks like a RIFF header.\n");
if(!rd->head_read(rd,&newhead))
return 0;
while(newhead != ('d'<<24)+('a'<<16)+('t'<<8)+'a') {
if(!rd->head_shift(rd,&newhead))
return 0;
}
if(!rd->head_read(rd,&newhead))
return 0;
if(param.verbose > 1) fprintf(stderr,"Note: Skipped RIFF header!\n");
goto read_again;
}
/* unhandled junk... just continue search for a header */
/* step in byte steps through next 64K */
for(i=0;i<65536;i++) {
if(!rd->head_shift(rd,&newhead))
return 0;
/* if(head_check(newhead)) */
if(head_check(newhead) && decode_header(fr, newhead))
break;
}
if(i == 65536) {
if(!param.quiet) error("Giving up searching valid MPEG header after 64K of junk.");
return 0;
}
/*
* should we additionaly check, whether a new frame starts at
* the next expected position? (some kind of read ahead)
* We could implement this easily, at least for files.
*/
}
#endif
/* first attempt of read ahead check to find the real first header; cannot believe what junk is out there! */
/* for now, a spurious first free format header screws up here; need free format support for detecting false free format headers... */
if(!firsthead && rd->flags & READER_SEEKABLE && head_check(newhead) && decode_header(fr, newhead))
{
unsigned long nexthead = 0;
int hd = 0;
off_t start = rd->tell(rd);
debug1("doing ahead check with BPF %d", fr->framesize+4);
/* step framesize bytes forward and read next possible header*/
if(rd->back_bytes(rd, -fr->framesize))
{
error("cannot seek!");
return 0;
}
hd = rd->head_read(rd,&nexthead);
if(rd->back_bytes(rd, rd->tell(rd)-start))
{
error("cannot seek!");
return 0;
}
if(!hd)
{
warning("cannot read next header, a one-frame stream? Duh...");
}
else
{
debug2("does next header 0x%08lx match first 0x%08lx?", nexthead, newhead);
/* not allowing free format yet */
if(!head_check(nexthead) || (nexthead & HDRCMPMASK) != (newhead & HDRCMPMASK))
{
debug("No, the header was not valid, start from beginning...");
/* try next byte for valid header */
if(rd->back_bytes(rd, 3))
{
error("cannot seek!");
return 0;
}
goto read_again;
}
}
}
/* why has this head check been avoided here before? */
if(!head_check(newhead))
{
if(!firsthead && free_format_header(newhead))
{
error1("Header 0x%08lx seems to indicate a free format stream; I do not handle that yet", newhead);
goto read_again;
return 0;
}
/* and those ugly ID3 tags */
if((newhead & 0xffffff00) == ('T'<<24)+('A'<<16)+('G'<<8)) {
rd->skip_bytes(rd,124);
if (param.verbose > 1) fprintf(stderr,"Note: Skipped ID3 Tag!\n");
goto read_again;
}
/* duplicated code from above! */
/* check for id3v2; first three bytes (of 4) are "ID3" */
if((newhead & (unsigned long) 0xffffff00) == (unsigned long) 0x49443300)
{
int id3length = 0;
id3length = parse_new_id3(newhead, rd);
goto read_again;
}
else if (give_note)
{
fprintf(stderr,"Note: Illegal Audio-MPEG-Header 0x%08lx at offset 0x%lx.\n", newhead,rd->tell(rd)-4);
}
if(give_note && (newhead & 0xffffff00) == ('b'<<24)+('m'<<16)+('p'<<8)) fprintf(stderr,"Note: Could be a BMP album art.\n");
if (param.tryresync || do_recover) {
int try = 0;
/* TODO: make this more robust, I'd like to cat two mp3 fragments together (in a dirty way) and still have mpg123 beign able to decode all it somehow. */
if(give_note) fprintf(stderr, "Note: Trying to resync...\n");
/* Read more bytes until we find something that looks
reasonably like a valid header. This is not a
perfect strategy, but it should get us back on the
track within a short time (and hopefully without
too much distortion in the audio output). */
do {
if(!rd->head_shift(rd,&newhead))
return 0;
/* debug2("resync try %i, got newhead 0x%08lx", try, newhead); */
if (!oldhead)
{
debug("going to init_resync...");
goto init_resync; /* "considered harmful", eh? */
}
/* we should perhaps collect a list of valid headers that occured in file... there can be more */
/* Michael's new resync routine seems to work better with the one frame readahead (and some input buffering?) */
} while
(
++try < RESYNC_LIMIT
&& (newhead & HDRCMPMASK) != (oldhead & HDRCMPMASK)
&& (newhead & HDRCMPMASK) != (firsthead & HDRCMPMASK)
);
/* too many false positives
}while (!(head_check(newhead) && decode_header(fr, newhead))); */
if(try == RESYNC_LIMIT)
{
error("giving up resync - your stream is not nice... perhaps an improved routine could catch up");
return 0;
}
if (give_note)
fprintf (stderr, "Note: Skipped %d bytes in input.\n", try);
}
else
{
error("not attempting to resync...");
return (0);
}
}
if (!firsthead) {
if(!decode_header(fr,newhead))
{
error("decode header failed before first valid one, going to read again");
goto read_again;
}
}
else
if(!decode_header(fr,newhead))
{
error("decode header failed - goto resync");
/* return 0; */
goto init_resync;
}
}
else
fr->header_change = 0;
#endif
bsbufold = bsbuf;
bsbuf = bsspace[bsnum]+512;
bsnum = (bsnum + 1) & 1;
/* if filepos is invalid, so is framepos */
//framepos = rd->filepos - 4;
/* read main data into memory */
/* 0 is error! */
if(!rd->read_frame_body(rd,bsbuf,fr->framesize))
return 0;
#if 0
if(!firsthead)
{
/* following stuff is actually layer3 specific (in practice, not in theory) */
if(fr->lay == 3)
{
/*
going to look for Xing or Info at some position after the header
MPEG 1 MPEG 2/2.5 (LSF)
Stereo, Joint Stereo, Dual Channel 32 17
Mono 17 9
Also, how to avoid false positives? I guess I should interpret more of the header to rule that out(?).
I hope that ensuring all zeros until tag start is enough.
*/
size_t lame_offset = (fr->stereo == 2) ? (fr->lsf ? 17 : 32 ) : (fr->lsf ? 9 : 17);
if(fr->framesize >= 120+lame_offset) /* traditional Xing header is 120 bytes */
{
size_t i;
int lame_type = 0;
/* only search for tag when all zero before it (apart from checksum) */
for(i=2; i < lame_offset; ++i) if(bsbuf[i] != 0) break;
if(i == lame_offset)
{
if
(
(bsbuf[lame_offset] == 'I')
&& (bsbuf[lame_offset+1] == 'n')
&& (bsbuf[lame_offset+2] == 'f')
&& (bsbuf[lame_offset+3] == 'o')
)
{
lame_type = 1; /* We still have to see what there is */
}
else if
(
(bsbuf[lame_offset] == 'X')
&& (bsbuf[lame_offset+1] == 'i')
&& (bsbuf[lame_offset+2] == 'n')
&& (bsbuf[lame_offset+3] == 'g')
)
{
lame_type = 2;
vbr = VBR; /* Xing header means always VBR */
}
if(lame_type)
{
unsigned long xing_flags;
/* we have one of these headers... */
if(param.verbose > 1) fprintf(stderr, "Note: Xing/Lame/Info header detected\n");
/* now interpret the Xing part, I have 120 bytes total for sure */
/* there are 4 bytes for flags, but only the last byte contains known ones */
lame_offset += 4; /* now first byte after Xing/Name */
/* 4 bytes dword for flags */
#define make_long(a, o) ((((unsigned long) a[o]) << 24) | (((unsigned long) a[o+1]) << 16) | (((unsigned long) a[o+2]) << 8) | ((unsigned long) a[o+3]))
/* 16 bit */
#define make_short(a,o) ((((unsigned short) a[o]) << 8) | ((unsigned short) a[o+1]))
xing_flags = make_long(bsbuf, lame_offset);
lame_offset += 4;
debug1("Xing: flags 0x%08lx", xing_flags);
if(xing_flags & 1) /* frames */
{
/*
In theory, one should use that value for skipping...
When I know the exact number of samples I could simply count in audio_flush,
but that's problematic with seeking and such.
I still miss the real solution for detecting the end.
*/
track_frames = make_long(bsbuf, lame_offset);
if(track_frames > TRACK_MAX_FRAMES) track_frames = 0; /* endless stream? */
#ifdef GAPLESS
/* if no further info there, remove/add at least the decoder delay */
if(param.gapless)
{
unsigned long length = track_frames * spf(fr);
if(length > 1)
layer3_gapless_init(DECODER_DELAY+GAP_SHIFT, length+DECODER_DELAY+GAP_SHIFT);
}
#endif
debug1("Xing: %lu frames", track_frames);
lame_offset += 4;
}
if(xing_flags & 0x2) /* bytes */
{
#ifdef DEBUG
unsigned long xing_bytes = make_long(bsbuf, lame_offset);
debug1("Xing: %lu bytes", xing_bytes);
#endif
lame_offset += 4;
}
if(xing_flags & 0x4) /* TOC */
{
lame_offset += 100; /* just skip */
}
if(xing_flags & 0x8) /* VBR quality */
{
#ifdef DEBUG
unsigned long xing_quality = make_long(bsbuf, lame_offset);
debug1("Xing: quality = %lu", xing_quality);
#endif
lame_offset += 4;
}
/* I guess that either 0 or LAME extra data follows */
/* there may this crc16 be floating around... (?) */
if(bsbuf[lame_offset] != 0)
{
unsigned char lame_vbr;
float replay_gain[2] = {0,0};
float peak = 0;
float gain_offset = 0; /* going to be +6 for old lame that used 83dB */
char nb[10];
memcpy(nb, bsbuf+lame_offset, 9);
nb[9] = 0;
debug1("Info: Encoder: %s", nb);
if(!strncmp("LAME", nb, 4))
{
gain_offset = 6;
debug("TODO: finish lame detetcion...");
}
lame_offset += 9;
/* the 4 big bits are tag revision, the small bits vbr method */
lame_vbr = bsbuf[lame_offset] & 15;
debug1("Info: rev %u", bsbuf[lame_offset] >> 4);
debug1("Info: vbr mode %u", lame_vbr);
lame_offset += 1;
switch(lame_vbr)
{
/* from rev1 proposal... not sure if all good in practice */
case 1:
case 8: vbr = CBR; break;
case 2:
case 9: vbr = ABR; break;
default: vbr = VBR; /* 00==unknown is taken as VBR */
}
/* skipping: lowpass filter value */
lame_offset += 1;
/* replaygain */
/* 32bit float: peak amplitude -- why did I parse it as int before??*/
/* Ah, yes, lame seems to store it as int since some day in 2003; I've only seen zeros anyway until now, bah! */
if
(
(bsbuf[lame_offset] != 0)
|| (bsbuf[lame_offset+1] != 0)
|| (bsbuf[lame_offset+2] != 0)
|| (bsbuf[lame_offset+3] != 0)
)
{
debug("Wow! Is there _really_ a non-zero peak value? Now is it stored as float or int - how should I know?");
peak = *(float*) (bsbuf+lame_offset);
}
debug1("Info: peak = %f (I won't use this)", peak);
peak = 0; /* until better times arrived */
lame_offset += 4;
/*
ReplayGain values - lame only writes radio mode gain...
16bit gain, 3 bits name, 3 bits originator, sign (1=-, 0=+), dB value*10 in 9 bits (fixed point)
ignore the setting if name or originator == 000!
radio 0 0 1 0 1 1 1 0 0 1 1 1 1 1 0 1
audiophile 0 1 0 0 1 0 0 0 0 0 0 1 0 1 0 0
*/
for(i =0; i < 2; ++i)
{
unsigned char origin = (bsbuf[lame_offset] >> 2) & 0x7; /* the 3 bits after that... */
if(origin != 0)
{
unsigned char gt = bsbuf[lame_offset] >> 5; /* only first 3 bits */
if(gt == 1) gt = 0; /* radio */
else if(gt == 2) gt = 1; /* audiophile */
else continue;
/* get the 9 bits into a number, divide by 10, multiply sign... happy bit banging */
replay_gain[0] = ((bsbuf[lame_offset] & 0x2) ? -0.1 : 0.1) * (make_short(bsbuf, lame_offset) & 0x1f);
}
lame_offset += 2;
}
debug1("Info: Radio Gain = %03.1fdB", replay_gain[0]);
debug1("Info: Audiophile Gain = %03.1fdB", replay_gain[1]);
for(i=0; i < 2; ++i)
{
if(rva_level[i] <= 0)
{
rva_peak[i] = 0; /* at some time the parsed peak should be used */
rva_gain[i] = replay_gain[i];
rva_level[i] = 0;
}
}
lame_offset += 1; /* skipping encoding flags byte */
if(vbr == ABR)
{
abr_rate = bsbuf[lame_offset];
debug1("Info: ABR rate = %u", abr_rate);
}
lame_offset += 1;
/* encoder delay and padding, two 12 bit values... lame does write them from int ...*/
#ifdef GAPLESS
if(param.gapless)
{
/*
Temporary hack that doesn't work with seeking and also is not waterproof but works most of the time;
in future the lame delay/padding and frame number info should be passed to layer3.c and the junk samples avoided at the source.
*/
unsigned long length = track_frames * spf(fr);
unsigned long skipbegin = DECODER_DELAY + ((((int) bsbuf[lame_offset]) << 4) | (((int) bsbuf[lame_offset+1]) >> 4));
unsigned long skipend = -DECODER_DELAY + (((((int) bsbuf[lame_offset+1]) << 8) | (((int) bsbuf[lame_offset+2]))) & 0xfff);
debug3("preparing gapless mode for layer3: length %lu, skipbegin %lu, skipend %lu", length, skipbegin, skipend);
if(length > 1)
layer3_gapless_init(skipbegin+GAP_SHIFT, (skipend < length) ? length-skipend+GAP_SHIFT : length+GAP_SHIFT);
}
#endif
}
/* switch buffer back ... */
bsbuf = bsspace[bsnum]+512;
bsnum = (bsnum + 1) & 1;
goto read_again;
}
}
}
} /* end block for Xing/Lame/Info tag */
firsthead = newhead; /* _now_ it's time to store it... the first real header */
debug1("firsthead: %08lx", firsthead);
/* now adjust volume */
do_rva();
/* and print id3 info */
if(!param.quiet) print_id3_tag(rd->flags & READER_ID3TAG ? rd->id3buf : NULL);
}
#endif
bsi.bitindex = 0;
bsi.wordpointer = (unsigned char *) bsbuf;
set_synth_functions(fr);
if (fr->error_protection)
getbits(16);
return 1;
}
#if 0
static int stream_back_bytes(struct reader *rds, off_t bytes)
{
if(stream_lseek(rds,-bytes,SEEK_CUR) < 0)
return -1;
/* you sure you want the buffer to resync here? */
if(param.usebuffer)
buffer_resync();
return 0;
}
/* this function strangely is define to seek num frames _back_ (and is called with -offset - duh!) */
/* also... let that int be a long in future! */
static int stream_back_frame(struct reader *rds,struct frame *fr,long num)
{
if(rds->flags & READER_SEEKABLE)
{
unsigned long newframe, preframe;
if(num > 0) /* back! */
{
if(num > fr->num) newframe = 0;
else newframe = fr->num-num;
}
else newframe = fr->num-num;
/* two leading frames? hm, doesn't seem to be really needed... */
/*if(newframe > 1) newframe -= 2;
else newframe = 0;*/
/* now seek to nearest leading index position and read from there until newframe is reached */
if(stream_lseek(rds,frame_index_find(newframe, &preframe),SEEK_SET) < 0)
return -1;
debug2("going to %lu; just got %lu", newframe, preframe);
fr->num = preframe;
while(fr->num < newframe)
{
/* try to be non-fatal now... frameNum only gets advanced on success anyway */
if(!read_frame(fr)) break;
}
/* this is not needed at last? */
/*read_frame(fr);
read_frame(fr);*/
if(fr->lay == 3) {
set_pointer(512);
}
debug1("arrived at %lu", fr->num);
if(param.usebuffer)
buffer_resync();
return 0;
}
else return -1; /* invalid, no seek happened */
}
static int stream_head_read(struct reader *rds,unsigned long *newhead)
{
unsigned char hbuf[4];
if(fullread(rds,hbuf,4) != 4)
return FALSE;
*newhead = ((unsigned long) hbuf[0] << 24) |
((unsigned long) hbuf[1] << 16) |
((unsigned long) hbuf[2] << 8) |
(unsigned long) hbuf[3];
return TRUE;
}
static int stream_head_shift(struct reader *rds,unsigned long *head)
{
unsigned char hbuf;
if(fullread(rds,&hbuf,1) != 1)
return 0;
*head <<= 8;
*head |= hbuf;
*head &= 0xffffffff;
return 1;
}
static off_t stream_skip_bytes(struct reader *rds,off_t len)
{
if (rds->filelen >= 0) {
off_t ret = stream_lseek(rds, len, SEEK_CUR);
if (param.usebuffer)
buffer_resync();
return ret;
} else if (len >= 0) {
unsigned char buf[1024]; /* ThOr: Compaq cxx complained and it makes sense to me... or should one do a cast? What for? */
off_t ret;
while (len > 0) {
off_t num = len < sizeof(buf) ? len : sizeof(buf);
ret = fullread(rds, buf, num);
if (ret < 0)
return ret;
len -= ret;
}
return rds->filepos;
} else
return -1;
}
static int stream_read_frame_body(struct reader *rds,unsigned char *buf,
int size)
{
long l;
if( (l=fullread(rds,buf,size)) != size)
{
if(l <= 0)
return 0;
memset(buf+l,0,size-l);
}
return 1;
}
static off_t stream_tell(struct reader *rds)
{
return rds->filepos;
}
static void stream_rewind(struct reader *rds)
{
stream_lseek(rds,0,SEEK_SET);
if(param.usebuffer)
buffer_resync();
}
static off_t get_fileinfo(struct reader *rds,char *buf)
{
off_t len;
if((len=lseek(rds->filept,0,SEEK_END)) < 0) {
return -1;
}
if(lseek(rds->filept,-128,SEEK_END) < 0)
return -1;
if(fullread(rds,(unsigned char *)buf,128) != 128) {
return -1;
}
if(!strncmp(buf,"TAG",3)) {
len -= 128;
}
if(lseek(rds->filept,0,SEEK_SET) < 0)
return -1;
if(len <= 0)
return -1;
return len;
}
#endif