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cog/Frameworks/mpg123/mpg123/parse.c

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/*
parse: spawned from common; clustering around stream/frame parsing
copyright ?-2012 by the mpg123 project - free software under the terms of the LGPL 2.1
see COPYING and AUTHORS files in distribution or http://mpg123.org
initially written by Michael Hipp & Thomas Orgis
*/
#include "mpg123lib_intern.h"
#include <sys/stat.h>
#include <fcntl.h>
#include "getbits.h"
#if defined (WANT_WIN32_SOCKETS)
#include <winsock2.h>
#include <ws2tcpip.h>
#endif
/* a limit for number of frames in a track; beyond that unsigned long may not be enough to hold byte addresses */
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif
#ifndef ULONG_MAX
/* hm, is this portable across preprocessors? */
#define ULONG_MAX ((unsigned long)-1)
#endif
#define TRACK_MAX_FRAMES ULONG_MAX/4/1152
#include "mpeghead.h"
#include "debug.h"
#define bsbufid(fr) (fr)->bsbuf==(fr)->bsspace[0] ? 0 : ((fr)->bsbuf==fr->bsspace[1] ? 1 : ( (fr)->bsbuf==(fr)->bsspace[0]+512 ? 2 : ((fr)->bsbuf==fr->bsspace[1]+512 ? 3 : -1) ) )
/* PARSE_GOOD and PARSE_BAD have to be 1 and 0 (TRUE and FALSE), others can vary. */
enum parse_codes
{
PARSE_MORE = MPG123_NEED_MORE
,PARSE_ERR = MPG123_ERR
,PARSE_END = 10 /* No more audio data to find. */
,PARSE_GOOD = 1 /* Everything's fine. */
,PARSE_BAD = 0 /* Not fine (invalid data). */
,PARSE_RESYNC = 2 /* Header not good, go into resync. */
,PARSE_AGAIN = 3 /* Really start over, throw away and read a new header, again. */
};
/* bitrates for [mpeg1/2][layer] */
static const 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,}
}
};
static const long freqs[9] = { 44100, 48000, 32000, 22050, 24000, 16000 , 11025 , 12000 , 8000 };
static int decode_header(mpg123_handle *fr,unsigned long newhead, int *freeformat_count);
static int skip_junk(mpg123_handle *fr, unsigned long *newheadp, long *headcount);
static int do_readahead(mpg123_handle *fr, unsigned long newhead);
static int wetwork(mpg123_handle *fr, unsigned long *newheadp);
/* These two are to be replaced by one function that gives all the frame parameters (for outsiders).*/
/* Those functions are unsafe regarding bad arguments (inside the mpg123_handle), but just returning anything would also be unsafe, the caller code has to be trusted. */
int frame_bitrate(mpg123_handle *fr)
{
return tabsel_123[fr->lsf][fr->lay-1][fr->bitrate_index];
}
long frame_freq(mpg123_handle *fr)
{
return freqs[fr->sampling_frequency];
}
/* compiler is smart enought to inline this one or should I really do it as macro...? */
static int head_check(unsigned long head)
{
if
(
((head & HDR_SYNC) != HDR_SYNC)
||
/* layer: 01,10,11 is 1,2,3; 00 is reserved */
(!(HDR_LAYER_VAL(head)))
||
/* 1111 means bad bitrate */
(HDR_BITRATE_VAL(head) == 0xf)
||
/* sampling freq: 11 is reserved */
(HDR_SAMPLERATE_VAL(head) == 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;
}
}
static int check_lame_tag(mpg123_handle *fr)
{
/*
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.
*/
int lame_offset = (fr->stereo == 2) ? (fr->lsf ? 17 : 32 ) : (fr->lsf ? 9 : 17);
if(fr->p.flags & MPG123_IGNORE_INFOFRAME) return 0;
/* Note: CRC or not, that does not matter here. */
if(fr->framesize >= 120+lame_offset) /* traditional Xing header is 120 bytes */
{
int i;
int lame_type = 0;
debug("do we have lame tag?");
/* only search for tag when all zero before it (apart from checksum) */
for(i=2; i < lame_offset; ++i) if(fr->bsbuf[i] != 0) break;
if(i == lame_offset)
{
debug("possibly...");
if
(
(fr->bsbuf[lame_offset] == 'I')
&& (fr->bsbuf[lame_offset+1] == 'n')
&& (fr->bsbuf[lame_offset+2] == 'f')
&& (fr->bsbuf[lame_offset+3] == 'o')
)
{
lame_type = 1; /* We still have to see what there is */
}
else if
(
(fr->bsbuf[lame_offset] == 'X')
&& (fr->bsbuf[lame_offset+1] == 'i')
&& (fr->bsbuf[lame_offset+2] == 'n')
&& (fr->bsbuf[lame_offset+3] == 'g')
)
{
lame_type = 2;
fr->vbr = MPG123_VBR; /* Xing header means always VBR */
}
if(lame_type)
{
unsigned long xing_flags;
/* we have one of these headers... */
if(VERBOSE2) 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(fr->bsbuf, lame_offset);
lame_offset += 4;
debug1("Xing: flags 0x%08lx", xing_flags);
if(xing_flags & 1) /* frames */
{
if(fr->p.flags & MPG123_IGNORE_STREAMLENGTH)
{
if(VERBOSE3)
fprintf(stderr, "Note: Ignoring Xing frames because of MPG123_IGNORE_STREAMLENGTH\n");
}
else
{
fr->track_frames = (off_t) make_long(fr->bsbuf, lame_offset);
if(fr->track_frames > TRACK_MAX_FRAMES) fr->track_frames = 0; /* endless stream? */
#ifdef GAPLESS
/* All or nothing: Only if encoder delay/padding is known we'll cut samples for gapless. */
if(fr->p.flags & MPG123_GAPLESS)
frame_gapless_init(fr, fr->track_frames, 0, 0);
#endif
if(VERBOSE3) fprintf(stderr, "Note: Xing: %lu frames\n", (long unsigned)fr->track_frames);
}
lame_offset += 4;
}
if(xing_flags & 0x2) /* bytes */
{
if(fr->p.flags & MPG123_IGNORE_STREAMLENGTH)
{
if(VERBOSE3)
fprintf(stderr, "Note: Ignoring Xing bytes because of MPG123_IGNORE_STREAMLENGTH\n");
}
else
{
unsigned long xing_bytes = make_long(fr->bsbuf, lame_offset); /* We assume that this is the _total_ size of the file, including Xing frame ... and ID3 frames...
It's not that clearly documented... */
if(fr->rdat.filelen < 1)
fr->rdat.filelen = (off_t) xing_bytes; /* One could start caring for overflow here. */
else
{
if((off_t) xing_bytes != fr->rdat.filelen && NOQUIET)
{
double diff = 1.0/fr->rdat.filelen * (fr->rdat.filelen - (off_t)xing_bytes);
if(diff < 0.) diff = -diff;
if(VERBOSE3)
fprintf(stderr, "Note: Xing stream size %lu differs by %f%% from determined/given file size!\n", xing_bytes, diff);
if(diff > 1.)
fprintf(stderr, "Warning: Xing stream size off by more than 1%%, fuzzy seeking may be even more fuzzy than by design!\n");
}
}
if(VERBOSE3)
fprintf(stderr, "Note: Xing: %lu bytes\n", (long unsigned)xing_bytes);
}
lame_offset += 4;
}
if(xing_flags & 0x4) /* TOC */
{
frame_fill_toc(fr, fr->bsbuf+lame_offset);
lame_offset += 100; /* just skip */
}
if(xing_flags & 0x8) /* VBR quality */
{
if(VERBOSE3)
{
unsigned long xing_quality = make_long(fr->bsbuf, lame_offset);
fprintf(stderr, "Note: Xing: quality = %lu\n", (long unsigned)xing_quality);
}
lame_offset += 4;
}
/* I guess that either 0 or LAME extra data follows */
if(fr->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, fr->bsbuf+lame_offset, 9);
nb[9] = 0;
if(VERBOSE3) fprintf(stderr, "Note: Info: Encoder: %s\n", nb);
if(!strncmp("LAME", nb, 4))
{
/* Lame versions before 3.95.1 used 83 dB reference level, later versions 89 dB.
We stick with 89 dB as being "normal", adding 6 dB. */
unsigned int major, minor;
char rest[6];
rest[0] = 0;
if(sscanf(nb+4, "%u.%u%s", &major, &minor, rest) >= 2)
{
debug3("LAME: %u/%u/%s", major, minor, rest);
/* We cannot detect LAME 3.95 reliably (same version string as 3.95.1), so this is a blind spot.
Everything < 3.95 is safe, though. */
if(major < 3 || (major == 3 && minor < 95)) /* || (major == 3 && minor == 95 && rest[0] == 0)) */
{
gain_offset = 6;
if(VERBOSE3) fprintf(stderr, "Note: Info: Old LAME detected, using ReplayGain preamp of %f dB.\n", gain_offset);
}
}
else if(VERBOSE3) fprintf(stderr, "Note: Info: Cannot determine LAME version.\n");
}
lame_offset += 9;
/* the 4 big bits are tag revision, the small bits vbr method */
lame_vbr = fr->bsbuf[lame_offset] & 15;
if(VERBOSE3)
{
fprintf(stderr, "Note: Info: rev %u\n", fr->bsbuf[lame_offset] >> 4);
fprintf(stderr, "Note: Info: vbr mode %u\n", lame_vbr);
}
lame_offset += 1;
switch(lame_vbr)
{
/* from rev1 proposal... not sure if all good in practice */
case 1:
case 8: fr->vbr = MPG123_CBR; break;
case 2:
case 9: fr->vbr = MPG123_ABR; break;
default: fr->vbr = MPG123_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
(
(fr->bsbuf[lame_offset] != 0)
|| (fr->bsbuf[lame_offset+1] != 0)
|| (fr->bsbuf[lame_offset+2] != 0)
|| (fr->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?");
/* byte*peak_bytes = (byte*) &peak;
... endianess ... just copy bytes to avoid floating point operation on unaligned memory?
peak_bytes[0] = ...
peak = *(float*) (fr->bsbuf+lame_offset); */
}
if(VERBOSE3) fprintf(stderr, "Note: Info: peak = %f (I won't use this)\n", 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 = (fr->bsbuf[lame_offset] >> 2) & 0x7; /* the 3 bits after that... */
if(origin != 0)
{
unsigned char gt = fr->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[gt] = (float) ((fr->bsbuf[lame_offset] & 0x2) ? -0.1 : 0.1) * (make_short(fr->bsbuf, lame_offset) & 0x1ff);
/* If this is an automatic value from LAME (or whatever), the automatic gain offset applies.
If a user or whoever set the value, do not touch it! 011 is automatic origin. */
if(origin == 3) replay_gain[gt] += gain_offset;
}
lame_offset += 2;
}
if(VERBOSE3)
{
fprintf(stderr, "Note: Info: Radio Gain = %03.1fdB\n", replay_gain[0]);
fprintf(stderr, "Note: Info: Audiophile Gain = %03.1fdB\n", replay_gain[1]);
}
for(i=0; i < 2; ++i)
{
if(fr->rva.level[i] <= 0)
{
fr->rva.peak[i] = 0; /* at some time the parsed peak should be used */
fr->rva.gain[i] = replay_gain[i];
fr->rva.level[i] = 0;
}
}
lame_offset += 1; /* skipping encoding flags byte */
if(fr->vbr == MPG123_ABR)
{
fr->abr_rate = fr->bsbuf[lame_offset];
if(VERBOSE3) fprintf(stderr, "Note: Info: ABR rate = %u\n", fr->abr_rate);
}
lame_offset += 1;
/* encoder delay and padding, two 12 bit values... lame does write them from int ...*/
if(VERBOSE3)
fprintf(stderr, "Note: Encoder delay = %i; padding = %i\n",
((((int) fr->bsbuf[lame_offset]) << 4) | (((int) fr->bsbuf[lame_offset+1]) >> 4)),
(((((int) fr->bsbuf[lame_offset+1]) << 8) | (((int) fr->bsbuf[lame_offset+2]))) & 0xfff) );
#ifdef GAPLESS
if(fr->p.flags & MPG123_GAPLESS)
{
off_t skipbegin = ((((int) fr->bsbuf[lame_offset]) << 4) | (((int) fr->bsbuf[lame_offset+1]) >> 4));
off_t skipend = (((((int) fr->bsbuf[lame_offset+1]) << 8) | (((int) fr->bsbuf[lame_offset+2]))) & 0xfff);
frame_gapless_init(fr, fr->track_frames, skipbegin, skipend);
}
#endif
}
/* switch buffer back ... */
fr->bsbuf = fr->bsspace[fr->bsnum]+512;
fr->bsnum = (fr->bsnum + 1) & 1;
return 1; /* got it! */
}
}
}
return 0; /* no lame tag */
}
/* Just tell if the header is some mono. */
static int header_mono(unsigned long newhead)
{
return HDR_CHANNEL_VAL(newhead) == MPG_MD_MONO ? TRUE : FALSE;
}
/* true if the two headers will work with the same decoding routines */
static int head_compatible(unsigned long fred, unsigned long bret)
{
return ( (fred & HDR_CMPMASK) == (bret & HDR_CMPMASK)
&& header_mono(fred) == header_mono(bret) );
}
static void halfspeed_prepare(mpg123_handle *fr)
{
/* save for repetition */
if(fr->p.halfspeed && fr->lay == 3)
{
debug("halfspeed - reusing old bsbuf ");
memcpy (fr->ssave, fr->bsbuf, fr->ssize);
}
}
/* If this returns 1, the next frame is the repetition. */
static int halfspeed_do(mpg123_handle *fr)
{
/* Speed-down hack: Play it again, Sam (the frame, I mean). */
if (fr->p.halfspeed)
{
if(fr->halfphase) /* repeat last frame */
{
debug("repeat!");
fr->to_decode = fr->to_ignore = TRUE;
--fr->halfphase;
fr->bitindex = 0;
fr->wordpointer = (unsigned char *) fr->bsbuf;
if(fr->lay == 3) memcpy (fr->bsbuf, fr->ssave, fr->ssize);
if(fr->error_protection) fr->crc = getbits(fr, 16); /* skip crc */
return 1;
}
else
{
fr->halfphase = (int)(fr->p.halfspeed - 1);
}
}
return 0;
}
/*
Temporary macro until we got this worked out.
Idea is to filter out special return values that shall trigger direct jumps to end / resync / read again.
Particularily, the generic ret==PARSE_BAD==0 and ret==PARSE_GOOD==1 are not affected.
*/
#define JUMP_CONCLUSION(ret) \
{ \
if(ret < 0){ debug1("%s", ret == MPG123_NEED_MORE ? "need more" : "read error"); goto read_frame_bad; } \
else if(ret == PARSE_AGAIN) goto read_again; \
else if(ret == PARSE_RESYNC) goto init_resync; \
else if(ret == PARSE_END) goto read_frame_bad; \
}
/*
That's a big one: read the next frame. 1 is success, <= 0 is some error
Special error READER_MORE means: Please feed more data and try again.
*/
int read_frame(mpg123_handle *fr)
{
/* TODO: rework this thing */
int freeformat_count = 0;
unsigned long newhead;
off_t framepos;
int ret;
/* stuff that needs resetting if complete frame reading fails */
int oldsize = fr->framesize;
int oldphase = fr->halfphase;
/* The counter for the search-first-header loop.
It is persistent outside the loop to prevent seemingly endless loops
when repeatedly headers are found that do not have valid followup headers. */
long headcount = 0;
fr->fsizeold=fr->framesize; /* for Layer3 */
if(halfspeed_do(fr) == 1) return 1;
read_again:
/* In case we are looping to find a valid frame, discard any buffered data before the current position.
This is essential to prevent endless looping, always going back to the beginning when feeder buffer is exhausted. */
if(fr->rd->forget != NULL) fr->rd->forget(fr);
debug2("trying to get frame %"OFF_P" at %"OFF_P, (off_p)fr->num+1, (off_p)fr->rd->tell(fr));
if((ret = fr->rd->head_read(fr,&newhead)) <= 0){ debug1("need more? (%i)", ret); goto read_frame_bad;}
init_resync:
fr->header_change = 2; /* output format change is possible... */
if(fr->oldhead) /* check a following header for change */
{
if(fr->oldhead == newhead) fr->header_change = 0;
else
/* Headers that match in this test behave the same for the outside world.
namely: same decoding routines, same amount of decoded data. */
if(head_compatible(fr->oldhead, newhead))
fr->header_change = 1;
}
#ifdef SKIP_JUNK
if(!fr->firsthead && !head_check(newhead))
{
ret = skip_junk(fr, &newhead, &headcount);
JUMP_CONCLUSION(ret);
}
#endif
ret = head_check(newhead);
if(ret) ret = decode_header(fr, newhead, &freeformat_count);
JUMP_CONCLUSION(ret); /* That only continues for ret == PARSE_BAD or PARSE_GOOD. */
if(ret == PARSE_BAD)
{ /* Header was not good. */
ret = wetwork(fr, &newhead); /* Messy stuff, handle junk, resync ... */
JUMP_CONCLUSION(ret);
/* Normally, we jumped already. If for some reason everything's fine to continue, do continue. */
if(ret != PARSE_GOOD) goto read_frame_bad;
}
if(!fr->firsthead)
{
ret = do_readahead(fr, newhead);
/* readahead can fail mit NEED_MORE, in which case we must also make the just read header available again for next go */
if(ret < 0) fr->rd->back_bytes(fr, 4);
JUMP_CONCLUSION(ret);
}
/* Now we should have our valid header and proceed to reading the frame. */
/* if filepos is invalid, so is framepos */
framepos = fr->rd->tell(fr) - 4;
/* flip/init buffer for Layer 3 */
{
unsigned char *newbuf = fr->bsspace[fr->bsnum]+512;
/* read main data into memory */
if((ret=fr->rd->read_frame_body(fr,newbuf,fr->framesize))<0)
{
/* if failed: flip back */
debug("need more?");
goto read_frame_bad;
}
fr->bsbufold = fr->bsbuf;
fr->bsbuf = newbuf;
}
fr->bsnum = (fr->bsnum + 1) & 1;
if(!fr->firsthead)
{
fr->firsthead = newhead; /* _now_ it's time to store it... the first real header */
/* This is the first header of our current stream segment.
It is only the actual first header of the whole stream when fr->num is still below zero!
Think of resyncs where firsthead has been reset for format flexibility. */
if(fr->num < 0)
{
fr->audio_start = framepos;
/* Only check for LAME tag at beginning of whole stream
... when there indeed is one in between, it's the user's problem. */
if(fr->lay == 3 && check_lame_tag(fr) == 1)
{ /* ...in practice, Xing/LAME tags are layer 3 only. */
if(fr->rd->forget != NULL) fr->rd->forget(fr);
fr->oldhead = 0;
goto read_again;
}
/* now adjust volume */
do_rva(fr);
}
debug2("fr->firsthead: %08lx, audio_start: %li", fr->firsthead, (long int)fr->audio_start);
}
fr->bitindex = 0;
fr->wordpointer = (unsigned char *) fr->bsbuf;
/* Question: How bad does the floating point value get with repeated recomputation?
Also, considering that we can play the file or parts of many times. */
if(++fr->mean_frames != 0)
{
fr->mean_framesize = ((fr->mean_frames-1)*fr->mean_framesize+compute_bpf(fr)) / fr->mean_frames ;
}
++fr->num; /* 0 for first frame! */
debug4("Frame %"OFF_P" %08lx %i, next filepos=%"OFF_P,
(off_p)fr->num, newhead, fr->framesize, (off_p)fr->rd->tell(fr));
if(!(fr->state_flags & FRAME_FRANKENSTEIN) && (
(fr->track_frames > 0 && fr->num >= fr->track_frames)
#ifdef GAPLESS
|| (fr->gapless_frames > 0 && fr->num >= fr->gapless_frames)
#endif
))
{
fr->state_flags |= FRAME_FRANKENSTEIN;
if(NOQUIET) fprintf(stderr, "\nWarning: Encountered more data after announced end of track (frame %"OFF_P"/%"OFF_P"). Frankenstein!\n", (off_p)fr->num,
#ifdef GAPLESS
fr->gapless_frames > 0 ? (off_p)fr->gapless_frames :
#endif
(off_p)fr->track_frames);
}
halfspeed_prepare(fr);
/* index the position */
fr->input_offset = framepos;
#ifdef FRAME_INDEX
/* Keep track of true frame positions in our frame index.
but only do so when we are sure that the frame number is accurate... */
if((fr->state_flags & FRAME_ACCURATE) && FI_NEXT(fr->index, fr->num))
fi_add(&fr->index, framepos);
#endif
if(fr->silent_resync > 0) --fr->silent_resync;
if(fr->rd->forget != NULL) fr->rd->forget(fr);
fr->to_decode = fr->to_ignore = TRUE;
if(fr->error_protection) fr->crc = getbits(fr, 16); /* skip crc */
fr->oldhead = newhead;
return 1;
read_frame_bad:
/* Also if we searched for valid data in vein, we can forget skipped data.
Otherwise, the feeder would hold every dead old byte in memory until the first valid frame! */
if(fr->rd->forget != NULL) fr->rd->forget(fr);
fr->silent_resync = 0;
if(fr->err == MPG123_OK) fr->err = MPG123_ERR_READER;
fr->framesize = oldsize;
fr->halfphase = oldphase;
/* That return code might be inherited from some feeder action, or reader error. */
return ret;
}
/*
* read ahead and find the next MPEG header, to guess framesize
* return value: success code
* PARSE_GOOD: found a valid frame size (stored in the handle).
* <0: error codes, possibly from feeder buffer (NEED_MORE)
* PARSE_BAD: cannot get the framesize for some reason and shall silentry try the next possible header (if this is no free format stream after all...)
*/
static int guess_freeformat_framesize(mpg123_handle *fr)
{
long i;
int ret;
unsigned long head;
if(!(fr->rdat.flags & (READER_SEEKABLE|READER_BUFFERED)))
{
if(NOQUIET) error("Cannot look for freeformat frame size with non-seekable and non-buffered stream!");
return PARSE_BAD;
}
if((ret=fr->rd->head_read(fr,&head))<=0)
return ret;
/* We are already 4 bytes into it */
for(i=4;i<MAXFRAMESIZE+4;i++)
{
if((ret=fr->rd->head_shift(fr,&head))<=0) return ret;
/* No head_check needed, the mask contains all relevant bits. */
if((head & HDR_SAMEMASK) == (fr->oldhead & HDR_SAMEMASK))
{
fr->rd->back_bytes(fr,i+1);
fr->framesize = (int)(i-3);
return PARSE_GOOD; /* Success! */
}
}
fr->rd->back_bytes(fr,i);
return PARSE_BAD;
}
/*
* decode a header and write the information
* into the frame structure
* Return values are compatible with those of read_frame, namely:
* 1: success
* 0: no valid header
* <0: some error
* You are required to do a head_check() before calling!
*/
static int decode_header(mpg123_handle *fr,unsigned long newhead, int *freeformat_count)
{
#ifdef DEBUG /* Do not waste cycles checking the header twice all the time. */
if(!head_check(newhead))
{
error1("trying to decode obviously invalid header 0x%08lx", newhead);
}
#endif
if(HDR_VERSION_VAL(newhead) & 0x2)
{
fr->lsf = (HDR_VERSION_VAL(newhead) & 0x1) ? 0 : 1;
fr->mpeg25 = 0;
}
else
{
fr->lsf = 1;
fr->mpeg25 = 1;
}
if( (fr->p.flags & MPG123_NO_RESYNC) || !fr->oldhead
|| (HDR_VERSION_VAL(fr->oldhead) != HDR_VERSION_VAL(newhead)) )
{
/* If "tryresync" is false, assume that certain
parameters do not change within the stream!
Force an update if lsf or mpeg25 settings
have changed. */
fr->lay = 4 - HDR_LAYER_VAL(newhead);
if(fr->mpeg25)
fr->sampling_frequency = 6 + HDR_SAMPLERATE_VAL(newhead);
else
fr->sampling_frequency = HDR_SAMPLERATE_VAL(newhead) + (fr->lsf*3);
}
#ifdef DEBUG
/* seen a file where this varies (old lame tag without crc, track with crc) */
if((HDR_CRC_VAL(newhead)^0x1) != fr->error_protection) debug("changed crc bit!");
#endif
fr->error_protection = HDR_CRC_VAL(newhead)^0x1;
fr->bitrate_index = HDR_BITRATE_VAL(newhead);
fr->padding = HDR_PADDING_VAL(newhead);
fr->extension = HDR_PRIVATE_VAL(newhead);
fr->mode = HDR_CHANNEL_VAL(newhead);
fr->mode_ext = HDR_CHANEX_VAL(newhead);
fr->copyright = HDR_COPYRIGHT_VAL(newhead);
fr->original = HDR_ORIGINAL_VAL(newhead);
fr->emphasis = HDR_EMPHASIS_VAL(newhead);
fr->freeformat = !(newhead & HDR_BITRATE);
fr->stereo = (fr->mode == MPG_MD_MONO) ? 1 : 2;
/* we can't use tabsel_123 for freeformat, so trying to guess framesize... */
if(fr->freeformat)
{
/* when we first encounter the frame with freeformat, guess framesize */
if(fr->freeformat_framesize < 0)
{
int ret;
*freeformat_count += 1;
if(*freeformat_count > 5)
{
if(VERBOSE3) error("You fooled me too often. Refusing to guess free format frame size _again_.");
return PARSE_BAD;
}
ret = guess_freeformat_framesize(fr);
if(ret == PARSE_GOOD)
{
fr->freeformat_framesize = fr->framesize - fr->padding;
if(VERBOSE2)
fprintf(stderr, "Note: free format frame size %li\n", fr->freeformat_framesize);
}
else
{
if(ret == MPG123_NEED_MORE)
debug("Need more data to guess free format frame size.");
else if(VERBOSE3)
error("Encountered free format header, but failed to guess frame size.");
return ret;
}
}
/* freeformat should be CBR, so the same framesize can be used at the 2nd reading or later */
else
{
fr->framesize = (int)(fr->freeformat_framesize + fr->padding);
}
}
switch(fr->lay)
{
#ifndef NO_LAYER1
case 1:
fr->do_layer = do_layer1;
if(!fr->freeformat)
{
fr->framesize = (int) tabsel_123[fr->lsf][0][fr->bitrate_index] * 12000;
fr->framesize /= freqs[fr->sampling_frequency];
fr->framesize = ((fr->framesize+fr->padding)<<2)-4;
}
break;
#endif
#ifndef NO_LAYER2
case 2:
fr->do_layer = do_layer2;
if(!fr->freeformat)
{
debug2("bitrate index: %i (%i)", fr->bitrate_index, tabsel_123[fr->lsf][1][fr->bitrate_index] );
fr->framesize = (int) tabsel_123[fr->lsf][1][fr->bitrate_index] * 144000;
fr->framesize /= freqs[fr->sampling_frequency];
fr->framesize += fr->padding - 4;
}
break;
#endif
#ifndef NO_LAYER3
case 3:
fr->do_layer = do_layer3;
if(fr->lsf)
fr->ssize = (fr->stereo == 1) ? 9 : 17;
else
fr->ssize = (fr->stereo == 1) ? 17 : 32;
if(fr->error_protection)
fr->ssize += 2;
if(!fr->freeformat)
{
fr->framesize = (int) 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;
#endif
default:
if(NOQUIET) error1("Layer type %i not supported in this build!", fr->lay);
return PARSE_BAD;
}
if (fr->framesize > MAXFRAMESIZE)
{
if(NOQUIET) error1("Frame size too big: %d", fr->framesize+4-fr->padding);
return PARSE_BAD;
}
return PARSE_GOOD;
}
void set_pointer(mpg123_handle *fr, long backstep)
{
fr->wordpointer = fr->bsbuf + fr->ssize - backstep;
if (backstep)
memcpy(fr->wordpointer,fr->bsbufold+fr->fsizeold-backstep,backstep);
fr->bitindex = 0;
}
/********************************/
double compute_bpf(mpg123_handle *fr)
{
double bpf;
switch(fr->lay)
{
case 1:
bpf = tabsel_123[fr->lsf][0][fr->bitrate_index];
bpf *= 12000.0 * 4.0;
bpf /= freqs[fr->sampling_frequency] <<(fr->lsf);
break;
case 2:
case 3:
bpf = tabsel_123[fr->lsf][fr->lay-1][fr->bitrate_index];
bpf *= 144000;
bpf /= freqs[fr->sampling_frequency] << (fr->lsf);
break;
default:
bpf = 1.0;
}
return bpf;
}
int attribute_align_arg mpg123_spf(mpg123_handle *mh)
{
if(mh == NULL) return MPG123_ERR;
return spf(mh);
}
double attribute_align_arg mpg123_tpf(mpg123_handle *fr)
{
static int bs[4] = { 0,384,1152,1152 };
double tpf;
if(fr == NULL) return -1;
tpf = (double) bs[fr->lay];
tpf /= freqs[fr->sampling_frequency] << (fr->lsf);
return tpf;
}
int attribute_align_arg mpg123_position(mpg123_handle *fr, off_t no, off_t buffsize,
off_t *current_frame, off_t *frames_left,
double *current_seconds, double *seconds_left)
{
double tpf;
double dt = 0.0;
off_t cur, left;
double curs, lefts;
if(!fr || !fr->rd) /* Isn't this too paranoid? */
{
debug("reader troubles!");
return MPG123_ERR;
}
no += fr->num; /* no starts out as offset */
cur = no;
tpf = mpg123_tpf(fr);
if(buffsize > 0 && fr->af.rate > 0 && fr->af.channels > 0)
{
dt = (double) buffsize / fr->af.rate / fr->af.channels;
if(fr->af.encoding & MPG123_ENC_16) dt *= 0.5;
}
left = 0;
if((fr->track_frames != 0) && (fr->track_frames >= fr->num)) left = no < fr->track_frames ? fr->track_frames - no : 0;
else
if(fr->rdat.filelen >= 0)
{
double bpf;
off_t t = fr->rd->tell(fr);
bpf = fr->mean_framesize ? fr->mean_framesize : compute_bpf(fr);
left = (off_t)((double)(fr->rdat.filelen-t)/bpf);
/* no can be different for prophetic purposes, file pointer is always associated with fr->num! */
if(fr->num != no)
{
if(fr->num > no) left += fr->num - no;
else
{
if(left >= (no - fr->num)) left -= no - fr->num;
else left = 0; /* uh, oh! */
}
}
/* I totally don't understand why we should re-estimate the given correct(?) value */
/* fr->num = (unsigned long)((double)t/bpf); */
}
/* beginning with 0 or 1?*/
curs = (double) no*tpf-dt;
lefts = (double)left*tpf+dt;
#if 0
curs = curs < 0 ? 0.0 : curs;
#endif
if(left < 0 || lefts < 0)
{ /* That is the case for non-seekable streams. */
left = 0;
lefts = 0.0;
}
if(current_frame != NULL) *current_frame = cur;
if(frames_left != NULL) *frames_left = left;
if(current_seconds != NULL) *current_seconds = curs;
if(seconds_left != NULL) *seconds_left = lefts;
return MPG123_OK;
}
int get_songlen(mpg123_handle *fr,int no)
{
double tpf;
if(!fr)
return 0;
if(no < 0) {
if(!fr->rd || fr->rdat.filelen < 0)
return 0;
no = (int) ((double) fr->rdat.filelen / compute_bpf(fr));
}
tpf = mpg123_tpf(fr);
return (int) (no*tpf);
}
/* first attempt of read ahead check to find the real first header; cannot believe what junk is out there! */
static int do_readahead(mpg123_handle *fr, unsigned long newhead)
{
unsigned long nexthead = 0;
int hd = 0;
off_t start, oret;
int ret;
if( ! (!fr->firsthead && fr->rdat.flags & (READER_SEEKABLE|READER_BUFFERED)) )
return PARSE_GOOD;
start = fr->rd->tell(fr);
debug2("doing ahead check with BPF %d at %"OFF_P, fr->framesize+4, (off_p)start);
/* step framesize bytes forward and read next possible header*/
if((oret=fr->rd->skip_bytes(fr, fr->framesize))<0)
{
if(oret==READER_ERROR && NOQUIET) error("cannot seek!");
return oret == MPG123_NEED_MORE ? PARSE_MORE : PARSE_ERR;
}
/* Read header, seek back. */
hd = fr->rd->head_read(fr,&nexthead);
if( fr->rd->back_bytes(fr, fr->rd->tell(fr)-start) < 0 )
{
if(NOQUIET) error("Cannot seek back!");
return PARSE_ERR;
}
if(hd == MPG123_NEED_MORE) return PARSE_MORE;
debug1("After fetching next header, at %"OFF_P, (off_p)fr->rd->tell(fr));
if(!hd)
{
if(NOQUIET) warning("Cannot read next header, a one-frame stream? Duh...");
return PARSE_END;
}
debug2("does next header 0x%08lx match first 0x%08lx?", nexthead, newhead);
if(!head_check(nexthead) || !head_compatible(newhead, nexthead))
{
debug("No, the header was not valid, start from beginning...");
fr->oldhead = 0; /* start over */
/* try next byte for valid header */
if((ret=fr->rd->back_bytes(fr, 3))<0)
{
if(NOQUIET) error("Cannot seek 3 bytes back!");
return PARSE_ERR;
}
return PARSE_AGAIN;
}
else return PARSE_GOOD;
}
static int handle_id3v2(mpg123_handle *fr, unsigned long newhead)
{
int ret;
fr->oldhead = 0; /* Think about that. Used to be present only for skipping of junk, not resync-style wetwork. */
ret = parse_new_id3(fr, newhead);
if (ret < 0) return ret;
#ifndef NO_ID3V2
else if(ret > 0){ debug("got ID3v2"); fr->metaflags |= MPG123_NEW_ID3|MPG123_ID3; }
else debug("no useful ID3v2");
#endif
return PARSE_AGAIN;
}
/* watch out for junk/tags on beginning of stream by invalid header */
static int skip_junk(mpg123_handle *fr, unsigned long *newheadp, long *headcount)
{
int ret;
int freeformat_count = 0;
long limit = 65536;
unsigned long newhead = *newheadp;
/* check for id3v2; first three bytes (of 4) are "ID3" */
if((newhead & (unsigned long) 0xffffff00) == (unsigned long) 0x49443300)
{
return handle_id3v2(fr, newhead);
}
else if(VERBOSE2 && fr->silent_resync == 0) 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(VERBOSE2 && fr->silent_resync == 0) fprintf(stderr, "Note: Looks like a RIFF header.\n");
if((ret=fr->rd->head_read(fr,&newhead))<=0) return ret;
while(newhead != ('d'<<24)+('a'<<16)+('t'<<8)+'a')
{
if((ret=fr->rd->head_shift(fr,&newhead))<=0) return ret;
}
if((ret=fr->rd->head_read(fr,&newhead))<=0) return ret;
if(VERBOSE2 && fr->silent_resync == 0) fprintf(stderr,"Note: Skipped RIFF header!\n");
fr->oldhead = 0;
*newheadp = newhead;
return PARSE_AGAIN;
}
/*
Unhandled junk... just continue search for a header, stepping in single bytes through next 64K.
This is rather identical to the resync loop.
*/
debug("searching for header...");
*newheadp = 0; /* Invalidate the external value. */
ret = 0; /* We will check the value after the loop. */
/* We prepare for at least the 64K bytes as usual, unless
user explicitly wanted more (even infinity). Never less. */
if(fr->p.resync_limit < 0 || fr->p.resync_limit > limit)
limit = fr->p.resync_limit;
do
{
++(*headcount);
if(limit >= 0 && *headcount >= limit) break;
if((ret=fr->rd->head_shift(fr,&newhead))<=0) return ret;
if(head_check(newhead) && (ret=decode_header(fr, newhead, &freeformat_count))) break;
} while(1);
if(ret<0) return ret;
if(limit >= 0 && *headcount >= limit)
{
if(NOQUIET) error1("Giving up searching valid MPEG header after %li bytes of junk.", *headcount);
return PARSE_END;
}
else debug1("hopefully found one at %"OFF_P, (off_p)fr->rd->tell(fr));
/* If the new header ist good, it is already decoded. */
*newheadp = newhead;
return PARSE_GOOD;
}
/* The newhead is bad, so let's check if it is something special, otherwise just resync. */
static int wetwork(mpg123_handle *fr, unsigned long *newheadp)
{
int ret = PARSE_ERR;
unsigned long newhead = *newheadp;
*newheadp = 0;
/* Classic ID3 tags. Read, then start parsing again. */
if((newhead & 0xffffff00) == ('T'<<24)+('A'<<16)+('G'<<8))
{
fr->id3buf[0] = (unsigned char) ((newhead >> 24) & 0xff);
fr->id3buf[1] = (unsigned char) ((newhead >> 16) & 0xff);
fr->id3buf[2] = (unsigned char) ((newhead >> 8) & 0xff);
fr->id3buf[3] = (unsigned char) ( newhead & 0xff);
if((ret=(int)fr->rd->fullread(fr,fr->id3buf+4,124)) < 0) return ret;
fr->metaflags |= MPG123_NEW_ID3|MPG123_ID3;
fr->rdat.flags |= READER_ID3TAG; /* that marks id3v1 */
if(VERBOSE3) fprintf(stderr,"Note: Skipped ID3v1 tag.\n");
return PARSE_AGAIN;
}
/* This is similar to initial junk skipping code... */
/* Check for id3v2; first three bytes (of 4) are "ID3" */
if((newhead & (unsigned long) 0xffffff00) == (unsigned long) 0x49443300)
{
return handle_id3v2(fr, newhead);
}
else if(NOQUIET && fr->silent_resync == 0)
{
fprintf(stderr,"Note: Illegal Audio-MPEG-Header 0x%08lx at offset %"OFF_P".\n",
newhead, (off_p)fr->rd->tell(fr)-4);
}
/* Now we got something bad at hand, try to recover. */
if(NOQUIET && (newhead & 0xffffff00) == ('b'<<24)+('m'<<16)+('p'<<8)) fprintf(stderr,"Note: Could be a BMP album art.\n");
if( !(fr->p.flags & MPG123_NO_RESYNC) )
{
long try = 0;
long limit = fr->p.resync_limit;
/* If a resync is needed the bitreservoir of previous frames is no longer valid */
fr->bitreservoir = 0;
if(NOQUIET && fr->silent_resync == 0) fprintf(stderr, "Note: Trying to resync...\n");
do /* ... shift the header with additional single bytes until be found something that could be a header. */
{
++try;
if(limit >= 0 && try >= limit) break;
if((ret=fr->rd->head_shift(fr,&newhead)) <= 0)
{
*newheadp = newhead;
if(NOQUIET) fprintf (stderr, "Note: Hit end of (available) data during resync.\n");
return ret ? ret : PARSE_END;
}
if(VERBOSE3) debug3("resync try %li at %"OFF_P", got newhead 0x%08lx", try, (off_p)fr->rd->tell(fr), newhead);
} while(!head_check(newhead));
*newheadp = newhead;
if(NOQUIET && fr->silent_resync == 0) fprintf (stderr, "Note: Skipped %li bytes in input.\n", try);
/* Now we either got something that could be a header, or we gave up. */
if(limit >= 0 && try >= limit)
{
if(NOQUIET)
error1("Giving up resync after %li bytes - your stream is not nice... (maybe increasing resync limit could help).", try);
fr->err = MPG123_RESYNC_FAIL;
return PARSE_ERR;
}
else
{
debug1("Found possibly valid header 0x%lx... unsetting firsthead to reinit stream.", newhead);
fr->firsthead = 0;
fr->oldhead = 0;
return PARSE_RESYNC;
}
}
else
{
if(NOQUIET) error("not attempting to resync...");
fr->err = MPG123_OUT_OF_SYNC;
return PARSE_ERR;
}
/* Control never goes here... we return before that. */
}
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