/* * Have fun reading the following: * * http://id3.org/id3v2.4.0-structure * http://id3.org/id3v2.4.0-frames * http://id3.org/d3v2.3.0 * http://id3.org/id3v2-00 * http://mpgedit.org/mpgedit/mpeg_format/mpeghdr.htm * http://wiki.hydrogenaud.io/index.php?title=MP3#VBRI.2C_XING.2C_and_LAME_headers * http://www.codeproject.com/Articles/8295/MPEG-Audio-Frame-Header#VBRIHeader */#include "tagspriv.h" #define synchsafe(d) (uint32_t)(((d)[0]&127)<<21 | ((d)[1]&127)<<14 | ((d)[2]&127)<<7 | ((d)[3]&127)<<0) static intv2cb(Tagctx *ctx, char *k, char *v){	k++;	if(strcmp(k, "AL") == 0 || strcmp(k, "ALB") == 0)		txtcb(ctx, Talbum, k-1, v);	else if(strcmp(k, "PE1") == 0 || strcmp(k, "P1") == 0)		txtcb(ctx, Tartist, k-1, v);	else if(strcmp(k, "PE2") == 0 || strcmp(k, "P2") == 0)		txtcb(ctx, Talbumartist, k-1, v);	else if(strcmp(k, "IT2") == 0 || strcmp(k, "T2") == 0)		txtcb(ctx, Ttitle, k-1, v);	else if(strcmp(k, "YE") == 0 || strcmp(k, "YER") == 0 || strcmp(k, "DRC") == 0)		txtcb(ctx, Tdate, k-1, v);	else if(strcmp(k, "RK") == 0 || strcmp(k, "RCK") == 0)		txtcb(ctx, Ttrack, k-1, v);	else if(strcmp(k, "LEN") == 0)		ctx->duration = atoi(v);	else if(strcmp(k, "CM") == 0 || strcmp(k, "COM") == 0)		txtcb(ctx, Tcomposer, k-1, v);	else if(strcmp(k, "CO") == 0 || strcmp(k, "CON") == 0){		for(; v[0]; v++){			if(v[0] == '(' && v[1] <= '9' && v[1] >= '0'){				int i = atoi(&v[1]);				if(i >= 0 && i < Numgenre)					txtcb(ctx, Tgenre, k-1, id3genres[i]);				for(v++; v[0] && v[0] != ')'; v++);				v--;			}else if(v[0] != '(' && v[0] != ')'){				txtcb(ctx, Tgenre, k-1, v);				break;			}		}	}else if(strcmp(k, "XXX") == 0 && strncmp(v, "REPLAYGAIN_", 11) == 0){		int type = -1;		v += 11;		if(strncmp(v, "TRACK_", 6) == 0){			v += 6;			if(strcmp(v, "GAIN") == 0)				type = Ttrackgain;			else if(strcmp(v, "PEAK") == 0)				type = Ttrackpeak;		}else if(strncmp(v, "ALBUM_", 6) == 0){			v += 6;			if(strcmp(v, "GAIN") == 0)				type = Talbumgain;			else if(strcmp(v, "PEAK") == 0)				type = Talbumpeak;		}		if(type >= 0)			txtcb(ctx, type, k-1, v+5);		else			return 0;	}else if(strcmp(k-1, "COM") == 0 || strcmp(k-1, "COMM") == 0){		txtcb(ctx, Tcomment, k-1, v);	}else{		txtcb(ctx, Tunknown, k-1, v);	}	return 1;} static intrva2(Tagctx *ctx, char *tag, int sz){	uint8_t *b, *end; 	if((b = memchr(tag, 0, sz)) == nil)		return -1;	b++;	for(end = (uint8_t*)tag+sz; b+4 < end; b += 5){		int type = b[0];		float peak;		float va = (float)(b[1]<<8 | b[2]) / 512.0f; 		if(b[3] == 24){			peak = (float)(b[4]<<16 | b[5]<<8 | b[6]) / 32768.0f;			b += 2;		}else if(b[3] == 16){			peak = (float)(b[4]<<8 | b[5]) / 32768.0f;			b += 1;		}else if(b[3] == 8){			peak = (float)b[4] / 32768.0f;		}else			return -1; 		if(type == 1){ /* master volume */			char vas[16], peaks[8];			snprintf(vas, sizeof(vas), "%+.5f dB", va);			snprintf(peaks, sizeof(peaks), "%.5f", peak);			vas[sizeof(vas)-1] = 0;			peaks[sizeof(peaks)-1] = 0; 			if(strcmp((char*)tag, "track") == 0){				txtcb(ctx, Ttrackgain, "RVA2", vas);				txtcb(ctx, Ttrackpeak, "RVA2", peaks);			}else if(strcmp((char*)tag, "album") == 0){				txtcb(ctx, Talbumgain, "RVA2", vas);				txtcb(ctx, Talbumpeak, "RVA2", peaks);			}			break;		}	}	return 0;} static intresync(uint8_t *b, int sz){	int i; 	if(sz < 4)		return sz;	for(i = 0; i < sz-2; i++){		if(b[i] == 0xff && b[i+1] == 0x00 && (b[i+2] & 0xe0) == 0xe0){			memmove(&b[i+1], &b[i+2], sz-i-2);			sz--;		}	}	return sz;} static intunsyncread(void *buf, int *sz){	int i;	uint8_t *b; 	b = buf;	for(i = 0; i < *sz; i++){		if(b[i] == 0xff){			if(i+1 >= *sz || (b[i+1] == 0x00 && i+2 >= *sz))				break;			if(b[i+1] == 0x00 && (b[i+2] & 0xe0) == 0xe0){				memmove(&b[i+1], &b[i+2], *sz-i-2);				(*sz)--;			}		}	}	return i;} static intnontext(Tagctx *ctx, uint8_t *d, int tsz, int unsync){	int n, offset;	char *b, *tag;	Tagdecode decf; 	tag = ctx->buf;	n = 0;	decf = unsync ? unsyncread : nil;	if(strcmp((char*)d, "APIC") == 0){		offset = ctx->seek(ctx, 0, 1);		if((n = ctx->read(ctx, tag, 255)) == 255){ /* APIC mime and description should fit */			tag[255] = 0;			b = tag + 1; /* mime type */			for(n = 1 + strlen(b) + 2; n < 253; n++){				if(tag[0] == 0 || tag[0] == 3){ /* one zero byte */					if(tag[n] == 0){						n++;						break;					}				}else if(tag[n] == 0 && tag[n+1] == 0 && tag[n+2] == 0){					n += 3;					break;				}			}			if(tsz > n){				tagscallcb(ctx, Timage, &(Tag){.image = {					.type = b[strlen(b)+1],					.mime = b,					.offset = offset+n,					.size = tsz-n,					.decode = decf,				}});			}			n = 255;		}	}else if(strcmp((char*)d, "PIC") == 0){		offset = ctx->seek(ctx, 0, 1);		if((n = ctx->read(ctx, tag, 255)) == 255){ /* PIC description should fit */			b = tag + 1; /* mime type */			for(n = 5; n < 253; n++){				if(tag[0] == 0 || tag[0] == 3){ /* one zero byte */					if(tag[n] == 0){						n++;						break;					}				}else if(tag[n] == 0 && tag[n+1] == 0 && tag[n+2] == 0){					n += 3;					break;				}			}			if(tsz > n){				tagscallcb(ctx, Timage, &(Tag){.image = {					.type = b[strlen(b)+1],					.mime = strcmp(b, "JPG") == 0 ? "image/jpeg" : "image/png",					.offset = offset+n,					.size = tsz-n,					.decode = decf,				}});			}			n = 255;		}	}else if(strcmp((char*)d, "RVA2") == 0 && tsz >= 6+5){		/* replay gain. 6 = "track\0", 5 = other */		if(ctx->bufsz >= tsz && (n = ctx->read(ctx, tag, tsz)) == tsz)			rva2(ctx, tag, unsync ? resync((uint8_t*)tag, n) : n);	} 	return ctx->seek(ctx, tsz-n, 1) < 0 ? -1 : 0;} static inttext(Tagctx *ctx, uint8_t *d, int tsz, int unsync){	char *b, *tag; 	if(tsz < 0)		return -1;	if(ctx->bufsz > tsz){		/* place the data at the end to make best effort at charset conversion */		tag = &ctx->buf[ctx->bufsz - tsz - 1];		if(ctx->read(ctx, tag, tsz) != tsz)			return -1;	}else{		ctx->seek(ctx, tsz, 1);		return 0;	} 	if(unsync)		tsz = resync((uint8_t*)tag, tsz); 	tag[tsz] = 0;	b = &tag[1]; 	switch(tag[0]){	case 0: /* iso-8859-1 */		if(iso88591toutf8((uint8_t*)ctx->buf, ctx->bufsz, (uint8_t*)b, tsz) > 0)			v2cb(ctx, (char*)d, ctx->buf);		break;	case 1: /* utf-16 */	case 2:		if(utf16to8((uint8_t*)ctx->buf, ctx->bufsz, (uint8_t*)b, tsz) > 0)			v2cb(ctx, (char*)d, ctx->buf);		break;	case 3: /* utf-8 */		if(*b)			v2cb(ctx, (char*)d, b);		break;	} 	return 0;} static intisid3(uint8_t *d){	/* "ID3" version[2] flags[1] size[4] */	return (		d[0] == 'I' && d[1] == 'D' && d[2] == '3' &&		d[3] < 0xff && d[4] < 0xff &&		d[6] < 0x80 && d[7] < 0x80 && d[8] < 0x80 && d[9] < 0x80	);} static const uint8_t bitrates[4][4][16] = {	{		{0},		{0,  4,  8, 12, 16, 20, 24, 28, 32, 40, 48, 56, 64,  72,  80, 0}, /* v2.5 III */		{0,  4,  8, 12, 16, 20, 24, 28, 32, 40, 48, 56, 64,  72,  80, 0}, /* v2.5 II */		{0, 16, 24, 28, 32, 40, 48, 56, 64, 72, 80, 88, 96, 112, 128, 0}, /* v2.5 I */	},	{ {0}, {0}, {0}, {0} },	{		{0},		{0,  4,  8, 12, 16, 20, 24, 28, 32, 40, 48, 56, 64,  72,  80, 0}, /* v2 III */		{0,  4,  8, 12, 16, 20, 24, 28, 32, 40, 48, 56, 64,  72,  80, 0}, /* v2 II */		{0, 16, 24, 28, 32, 40, 48, 56, 64, 72, 80, 88, 96, 112, 128, 0}, /* v2 I */	},	{		{0},		{0, 16, 20, 24, 28, 32, 40,  48,  56,  64,  80,  96, 112, 128, 160, 0}, /* v1 III */		{0, 16, 24, 28, 32, 40, 48,  56,  64,  80,  96, 112, 128, 160, 192, 0}, /* v1 II */		{0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 0}, /* v1 I */	}}; static const uint32_t samplerates[4][4] = {	{11025, 12000,  8000, 0},	{    0,     0,     0, 0},	{22050, 24000, 16000, 0},	{44100, 48000, 32000, 0},}; static const int chans[] = {2, 2, 2, 1}; static const int samplesframe[4][4] = {	{0,    0,    0,   0},	{0,  576, 1152, 384},	{0,  576, 1152, 384},	{0, 1152, 1152, 384},}; static voidgetduration(Tagctx *ctx, int offset){	uint64_t n, framelen, samplespf, toc;	uint8_t *b;	uint32_t x;	int xversion, xlayer, xbitrate, i; 	if(ctx->duration != 0 || ctx->read(ctx, ctx->buf, 256) != 256)		return; 	x = beuint((uint8_t*)ctx->buf);	xversion = x >> 19 & 3;	xlayer = x >> 17 & 3;	xbitrate = x >> 12 & 0xf;	ctx->bitrate = 2000*(int)bitrates[xversion][xlayer][xbitrate];	samplespf = samplesframe[xversion][xlayer]; 	ctx->samplerate = samplerates[xversion][x >> 10 & 3];	ctx->channels = chans[x >> 6 & 3]; 	if(ctx->samplerate > 0){		framelen = (uint64_t)144*ctx->bitrate / ctx->samplerate;		if((x & (1<<9)) != 0) /* padding */			framelen += xlayer == 3 ? 4 : 1; /* for I it's 4 bytes */ 		if(memcmp(&ctx->buf[0x24], "Info", 4) == 0 || memcmp(&ctx->buf[0x24], "Xing", 4) == 0){			b = (uint8_t*)ctx->buf + 0x28;			x = beuint(b); b += 4;			if((x & 1) != 0){ /* number of frames is set */				n = beuint(b); b += 4;				ctx->duration = n * samplespf * 1000 / ctx->samplerate;			} 			if((x & 2) != 0){ /* file size is set */				n = beuint(b); b += 4;				if(ctx->duration == 0 && framelen > 0)					ctx->duration = n * samplespf * 1000 / framelen / ctx->samplerate; 				if((x & 4) != 0 && ctx->toc != nil){ /* TOC is set */					toc = offset + 100 + (char*)b - ctx->buf;					if((x & 8) != 0) /* VBR scale */						toc += 4;					for(i = 0; i < 100; i++){						/*						 * offset = n * b[i] / 256						 * ms = i * duration / 100						 */						ctx->toc(ctx, i * ctx->duration / 100, toc + (n * b[i]) / 256);					}					b += 100;					if((x & 8) != 0) /* VBR scale */						b += 4;				}			}			offset += (char*)b - ctx->buf;		}else if(memcmp(&ctx->buf[0x24], "VBRI", 4) == 0){			n = beuint((uint8_t*)&ctx->buf[0x32]);			ctx->duration = n * samplespf * 1000 / ctx->samplerate; 			if(ctx->duration == 0 && framelen > 0){				n = beuint((uint8_t*)&ctx->buf[0x28]); /* file size */				ctx->duration = n * samplespf * 1000 / framelen / ctx->samplerate;			}		}	} 	if(ctx->bitrate > 0 && ctx->duration == 0) /* worst case -- use real file size instead */		ctx->duration = (ctx->seek(ctx, 0, 2) - offset)/(ctx->bitrate / 1000) * 8;} inttagid3v2(Tagctx *ctx){	int sz, exsz, framesz;	int ver, unsync, offset;	int newpos, oldpos;	uint8_t d[10], *b, *e; 	if(ctx->read(ctx, d, sizeof(d)) != sizeof(d))		return -1;	if(!isid3(d)){ /* no tags, but the stream information is there */		if(d[0] != 0xff || (d[1] & 0xfe) != 0xfa)			return -1;		ctx->seek(ctx, -(int)sizeof(d), 1);		getduration(ctx, 0);		return 0;	} 	oldpos = 0;header:	ver = d[3];	unsync = d[5] & (1<<7);	sz = synchsafe(&d[6]); 	if(ver == 2 && (d[5] & (1<<6)) != 0) /* compression */		return -1; 	ctx->restart = sizeof(d)+sz; 	if(ver > 2){		if((d[5] & (1<<4)) != 0) /* footer */			sz -= 10;		if((d[5] & (1<<6)) != 0){ /* skip extended header */			if(ctx->read(ctx, d, 4) != 4)				return -1;			exsz = (ver >= 3) ? beuint(d) : synchsafe(d);			if(exsz < 6 || ctx->seek(ctx, exsz-4, 1) < 0)				return -1;			sz -= exsz;		}	} 	framesz = (ver >= 3) ? 10 : 6;	for(; sz > framesz;){		int tsz, frameunsync; 		if(ctx->read(ctx, d, framesz) != framesz)			return -1;		sz -= framesz; 		/* return on padding */		if(memcmp(d, "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", framesz) == 0)			break;		if(ver >= 3){			tsz = (ver == 3) ? beuint(&d[4]) : synchsafe(&d[4]);			if(tsz < 0 || tsz > sz)				break;			frameunsync = d[9] & (1<<1);			d[4] = 0; 			if((d[9] & 0x0c) != 0){ /* compression & encryption */				ctx->seek(ctx, tsz, 1);				sz -= tsz;				continue;			}			if(ver == 4 && (d[9] & 1<<0) != 0){ /* skip data length indicator */				ctx->seek(ctx, 4, 1);				sz -= 4;				tsz -= 4;			}		}else{			tsz = beuint(&d[3]) >> 8;			if(tsz > sz)				return -1;			frameunsync = 0;			d[3] = 0;		}		sz -= tsz; 		if(d[0] == 'T' && text(ctx, d, tsz, unsync || frameunsync) != 0)			return -1;		else if(d[0] != 'T' && nontext(ctx, d, tsz, unsync || frameunsync) != 0)			return -1;	} 	offset = ctx->seek(ctx, sz, 1);	sz = ctx->bufsz <= 2048 ? ctx->bufsz : 2048;	e = (uint8_t*)ctx->buf + sz - 3;	b = nil;	for(exsz = 0; exsz < 2048; exsz += sz){		if(ctx->read(ctx, ctx->buf, sz) != sz)			break;		for(b = (uint8_t*)ctx->buf; (b = memchr(b, 'I', sz - 1 - ((char*)b - ctx->buf))) != nil; b++){			newpos = ctx->seek(ctx, (char*)b - ctx->buf + offset + exsz, 0);			if(ctx->read(ctx, d, sizeof(d)) != sizeof(d))				return 0;			if(isid3(d) && newpos > oldpos){				oldpos = newpos;				goto header;			}		}		for(b = (uint8_t*)ctx->buf; b < e && (b = memchr(b, 0xff, e-b)) != nil; b++){			if((b[1] & 0xe0) == 0xe0){				offset = ctx->seek(ctx, (char*)b - ctx->buf + offset + exsz, 0);				exsz = 2048;				break;			}		}	} 

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