id3.c

mips上编译过的mpg 运行正常 环境：AU12

	if(VERBOSE3) fprintf(stderr, "Ignoring untranslated ID3v2.2 frame %c%c%c\n", id[0], id[1], id[2]);
	return -1;
}

/*
	trying to parse ID3v2.3 and ID3v2.4 tags...

	returns:  0: bad or just unparseable tag
	          1: good, (possibly) new tag info
	         <0: reader error (may need more data feed, try again)
*/
int parse_new_id3(mpg123_handle *fr, unsigned long first4bytes)
{
	#define UNSYNC_FLAG 128
	#define EXTHEAD_FLAG 64
	#define EXP_FLAG 32
	#define FOOTER_FLAG 16
	#define UNKNOWN_FLAGS 15 /* 00001111*/
	unsigned char buf[6];
	unsigned long length=0;
	unsigned char flags = 0;
	int ret = 1;
	int ret2;
	unsigned char* tagdata = NULL;
	unsigned char major = first4bytes & 0xff;
	debug1("ID3v2: major tag version: %i", major);
	if(major == 0xff) return 0; /* Invalid... */
	if((ret2 = fr->rd->read_frame_body(fr, buf, 6)) < 0) /* read more header information */
	return ret2;

	if(buf[0] == 0xff) return 0; /* Revision, will never be 0xff. */

	/* second new byte are some nice flags, if these are invalid skip the whole thing */
	flags = buf[1];
	debug1("ID3v2: flags 0x%08x", flags);
	/* use 4 bytes from buf to construct 28bit uint value and return 1; return 0 if bytes are not synchsafe */
	#define synchsafe_to_long(buf,res) \
	( \
		(((buf)[0]|(buf)[1]|(buf)[2]|(buf)[3]) & 0x80) ? 0 : \
		(res =  (((unsigned long) (buf)[0]) << 21) \
		     | (((unsigned long) (buf)[1]) << 14) \
		     | (((unsigned long) (buf)[2]) << 7) \
		     |  ((unsigned long) (buf)[3]) \
		,1) \
	)
	/* id3v2.3 does not store synchsafe frame sizes, but synchsafe tag size - doh! */
	#define bytes_to_long(buf,res) \
	( \
		major == 3 ? \
		(res =  (((unsigned long) (buf)[0]) << 24) \
		     | (((unsigned long) (buf)[1]) << 16) \
		     | (((unsigned long) (buf)[2]) << 8) \
		     |  ((unsigned long) (buf)[3]) \
		,1) : synchsafe_to_long(buf,res) \
	)
	/* for id3v2.2 only */
	#define threebytes_to_long(buf,res) \
	( \
		res =  (((unsigned long) (buf)[0]) << 16) \
		     | (((unsigned long) (buf)[1]) << 8) \
		     |  ((unsigned long) (buf)[2]) \
		,1 \
	)

	/* length-10 or length-20 (footer present); 4 synchsafe integers == 28 bit number  */
	/* we have already read 10 bytes, so left are length or length+10 bytes belonging to tag */
	if(!synchsafe_to_long(buf+2,length))
	{
		if(NOQUIET) error4("Bad tag length (not synchsafe): 0x%02x%02x%02x%02x; You got a bad ID3 tag here.", buf[2],buf[3],buf[4],buf[5]);
		return 0;
	}
	debug1("ID3v2: tag data length %lu", length);
	if(VERBOSE2) fprintf(stderr,"Note: ID3v2.%i rev %i tag of %lu bytes\n", major, buf[0], length);
	/* skip if unknown version/scary flags, parse otherwise */
	if((flags & UNKNOWN_FLAGS) || (major > 4) || (major < 2))
	{
		/* going to skip because there are unknown flags set */
		if(NOQUIET) warning2("ID3v2: Won't parse the ID3v2 tag with major version %u and flags 0x%xu - some extra code may be needed", major, flags);
		if((ret2 = fr->rd->skip_bytes(fr,length)) < 0) /* will not store data in backbuff! */
		ret = ret2;
	}
	else
	{
		fr->id3v2.version = major;
		/* try to interpret that beast */
		if((tagdata = (unsigned char*) malloc(length+1)) != NULL)
		{
			debug("ID3v2: analysing frames...");
			if((ret2 = fr->rd->read_frame_body(fr,tagdata,length)) > 0)
			{
				unsigned long tagpos = 0;
				debug1("ID3v2: have read at all %lu bytes for the tag now", (unsigned long)length+6);
				/* going to apply strlen for strings inside frames, make sure that it doesn't overflow! */
				tagdata[length] = 0;
				if(flags & EXTHEAD_FLAG)
				{
					debug("ID3v2: skipping extended header");
					if(!bytes_to_long(tagdata, tagpos))
					{
						ret = 0;
						if(NOQUIET) error4("Bad (non-synchsafe) tag offset: 0x%02x%02x%02x%02x", tagdata[0], tagdata[1], tagdata[2], tagdata[3]);
					}
				}
				if(ret > 0)
				{
					char id[5];
					unsigned long framesize;
					unsigned long fflags; /* need 16 bits, actually */
					id[4] = 0;
					/* pos now advanced after ext head, now a frame has to follow */
					while(tagpos < length-10) /* I want to read at least a full header */
					{
						int i = 0;
						unsigned long pos = tagpos;
						int head_part = fr->id3v2.version == 2 ? 3 : 4; /* bytes of frame title and of framesize value */
						/* level 1,2,3 - 0 is info from lame/info tag! */
						/* rva tags with ascending significance, then general frames */
						#define KNOWN_FRAMES 3
						const char frame_type[KNOWN_FRAMES][5] = { "COMM", "TXXX", "RVA2" }; /* plus all text frames... */
						enum { unknown = -2, text = -1, comment, extra, rva2 } tt = unknown;
						/* we may have entered the padding zone or any other strangeness: check if we have valid frame id characters */
						for(i=0; i< head_part; ++i)
						if( !( ((tagdata[tagpos+i] > 47) && (tagdata[tagpos+i] < 58))
						    || ((tagdata[tagpos+i] > 64) && (tagdata[tagpos+i] < 91)) ) )
						{
							debug5("ID3v2: real tag data apparently ended after %lu bytes with 0x%02x%02x%02x%02x", tagpos, tagdata[tagpos], tagdata[tagpos+1], tagdata[tagpos+2], tagdata[tagpos+3]);
							/* This is no hard error... let's just hope that we got something meaningful already (ret==1 in that case). */
							goto tagparse_cleanup; /* Need to escape two loops here. */
						}
						if(ret > 0)
						{
							/* 4 or 3 bytes id */
							strncpy(id, (char*) tagdata+pos, head_part);
							pos += head_part;
							tagpos += head_part;
							/* size as 32 bits or 28 bits */
							if(fr->id3v2.version == 2) threebytes_to_long(tagdata+pos, framesize);
							else
							if(!bytes_to_long(tagdata+pos, framesize))
							{
								/* Just assume that up to now there was some good data. */
								if(NOQUIET) error1("ID3v2: non-syncsafe size of %s frame, skipping the remainder of tag", id);
								break;
							}
							if(VERBOSE3) fprintf(stderr, "Note: ID3v2 %s frame of size %lu\n", id, framesize);
							tagpos += head_part + framesize; /* the important advancement in whole tag */
							if(tagpos > length)
							{
								if(NOQUIET) error("Whoa! ID3v2 frame claims to be larger than the whole rest of the tag.");
								break;
							}
							pos += head_part;
							if(fr->id3v2.version > 2)
							{
								fflags  = (((unsigned long) tagdata[pos]) << 8) | ((unsigned long) tagdata[pos+1]);
								pos    += 2;
								tagpos += 2;
							}
							else fflags = 0;
							/* for sanity, after full parsing tagpos should be == pos */
							/* debug4("ID3v2: found %s frame, size %lu (as bytes: 0x%08lx), flags 0x%016lx", id, framesize, framesize, fflags); */
							/* %0abc0000 %0h00kmnp */
							#define BAD_FFLAGS (unsigned long) 36784
							#define PRES_TAG_FFLAG 16384
							#define PRES_FILE_FFLAG 8192
							#define READ_ONLY_FFLAG 4096
							#define GROUP_FFLAG 64
							#define COMPR_FFLAG 8
							#define ENCR_FFLAG 4
							#define UNSYNC_FFLAG 2
							#define DATLEN_FFLAG 1
							if(head_part < 4 && promote_framename(fr, id) != 0) continue;

							/* shall not or want not handle these */
							if(fflags & (BAD_FFLAGS | COMPR_FFLAG | ENCR_FFLAG))
							{
								if(NOQUIET) warning("ID3v2: skipping invalid/unsupported frame");
								continue;
							}
							
							for(i = 0; i < KNOWN_FRAMES; ++i)
							if(!strncmp(frame_type[i], id, 4)){ tt = i; break; }

							if(id[0] == 'T' && tt != extra) tt = text;

							if(tt != unknown)
							{
								int rva_mode = -1; /* mix / album */
								unsigned long realsize = framesize;
								unsigned char* realdata = tagdata+pos;
								if((flags & UNSYNC_FLAG) || (fflags & UNSYNC_FFLAG))
								{
									unsigned long ipos = 0;
									unsigned long opos = 0;
									debug("Id3v2: going to de-unsync the frame data");
									/* de-unsync: FF00 -> FF; real FF00 is simply represented as FF0000 ... */
									/* damn, that means I have to delete bytes from withing the data block... thus need temporal storage */
									/* standard mandates that de-unsync should always be safe if flag is set */
									realdata = (unsigned char*) malloc(framesize); /* will need <= bytes */
									if(realdata == NULL)
									{
										if(NOQUIET) error("ID3v2: unable to allocate working buffer for de-unsync");
										continue;
									}
									/* now going byte per byte through the data... */
									realdata[0] = tagdata[pos];
									opos = 1;
									for(ipos = pos+1; ipos < pos+framesize; ++ipos)
									{
										if(!((tagdata[ipos] == 0) && (tagdata[ipos-1] == 0xff)))
										{
											realdata[opos++] = tagdata[ipos];
										}
									}
									realsize = opos;
									debug2("ID3v2: de-unsync made %lu out of %lu bytes", realsize, framesize);
								}
								pos = 0; /* now at the beginning again... */
								switch(tt)
								{
									case comment:
										process_comment(fr, (char*)realdata, realsize, comment+1, id);
									break;
									case extra: /* perhaps foobar2000's work */
										process_extra(fr, (char*)realdata, realsize, extra+1, id);
									break;
									case rva2: /* "the" RVA tag */
									{
										#ifdef HAVE_INTTYPES_H
										/* starts with null-terminated identification */
										if(VERBOSE3) fprintf(stderr, "Note: RVA2 identification \"%s\"\n", realdata);
										/* default: some individual value, mix mode */
										rva_mode = 0;
										if( !strncasecmp((char*)realdata, "album", 5)
										    || !strncasecmp((char*)realdata, "audiophile", 10)
										    || !strncasecmp((char*)realdata, "user", 4))
										rva_mode = 1;
										if(fr->rva.level[rva_mode] <= rva2+1)
										{
											pos += strlen((char*) realdata) + 1;
											if(realdata[pos] == 1)
											{
												++pos;
												/* only handle master channel */
												debug("ID3v2: it is for the master channel");
												/* two bytes adjustment, one byte for bits representing peak - n bytes for peak */
												/* 16 bit signed integer = dB * 512 */
												/* we already assume short being 16 bit */
												fr->rva.gain[rva_mode] = (float) ((((short) realdata[pos]) << 8) | ((short) realdata[pos+1])) / 512;
												pos += 2;
												if(VERBOSE3) fprintf(stderr, "Note: RVA value %fdB\n", fr->rva.gain[rva_mode]);
												/* heh, the peak value is represented by a number of bits - but in what manner? Skipping that part */
												fr->rva.peak[rva_mode] = 0;
												fr->rva.level[rva_mode] = rva2+1;
											}
										}
										#else
										if(NOQUIET) warning("ID3v2: Cannot parse RVA2 value because I don't have a guaranteed 16 bit signed integer type");
										#endif
									}
									break;
									/* non-rva metainfo, simply store... */
									case text:
										process_text(fr, (char*)realdata, realsize, id);
									break;
									default: if(NOQUIET) error1("ID3v2: unknown frame type %i", tt);
								}
								if((flags & UNSYNC_FLAG) || (fflags & UNSYNC_FFLAG)) free(realdata);
							}
							#undef BAD_FFLAGS
							#undef PRES_TAG_FFLAG
							#undef PRES_FILE_FFLAG
							#undef READ_ONLY_FFLAG
							#undef GROUP_FFLAG
							#undef COMPR_FFLAG
							#undef ENCR_FFLAG
							#undef UNSYNC_FFLAG
							#undef DATLEN_FFLAG
						}
						else break;
						#undef KNOWN_FRAMES
					}
				}
			}
			else
			{
				if(NOQUIET) error("ID3v2: Duh, not able to read ID3v2 tag data.");
				ret = ret2;
			}
tagparse_cleanup:
			free(tagdata);
		}
		else
		{
			if(NOQUIET) error1("ID3v2: Arrg! Unable to allocate %lu bytes for interpreting ID3v2 data - trying to skip instead.", length);
			if((ret2 = fr->rd->skip_bytes(fr,length)) < 0) ret = ret2; /* will not store data in backbuff! */
			else ret = 0;
		}
	}
	/* skip footer if present */
	if((ret > 0) && (flags & FOOTER_FLAG) && ((ret2 = fr->rd->skip_bytes(fr,length)) < 0)) ret = ret2;

	return ret;
	#undef UNSYNC_FLAG
	#undef EXTHEAD_FLAG
	#undef EXP_FLAG
	#undef FOOTER_FLAG
	#undef UNKOWN_FLAGS
}

static void convert_latin1(mpg123_string *sb, unsigned char* s, size_t l)
{
	size_t length = l;
	size_t i;
	unsigned char *p;
	/* determine real length, a latin1 character can at most take 2  in UTF8 */
	for(i=0; i<l; ++i)
	if(s[i] >= 0x80) ++length;

	debug1("UTF-8 length: %lu", (unsigned long)length);
	/* one extra zero byte for paranoia */
	if(!mpg123_resize_string(sb, length+1)){ mpg123_free_string(sb); return ; }

	p = (unsigned char*) sb->p; /* Signedness doesn't matter but it shows I thought about the non-issue */
	for(i=0; i<l; ++i)
	if(s[i] < 0x80){ *p = s[i]; ++p; }
	else /* two-byte encoding */
	{
		*p     = 0xc0 | (s[i]>>6);
		*(p+1) = 0x80 | (s[i] & 0x3f);
		p+=2;
	}

	sb->p[length] = 0;
	sb->fill = length+1;
}

#define FULLPOINT(f,s) ( (((f)&0x3ff)<<10) + ((s)&0x3ff) + 0x10000 )
/* Remember: There's a limit at 0x1ffff. */
#define UTF8LEN(x) ( (x)<0x80 ? 1 : ((x)<0x800 ? 2 : ((x)<0x10000 ? 3 : 4)))
static void convert_utf16(mpg123_string *sb, unsigned char* s, size_t l, int str_be)
{
	size_t i;
	unsigned char *p;
	size_t length = 0; /* the resulting UTF-8 length */
	/* Determine real length... extreme case can be more than utf-16 length. */
	size_t high = 0;
	size_t low  = 1;
	debug1("convert_utf16 with length %lu", (unsigned long)l);
	if(!str_be) /* little-endian */
	{
		high = 1; /* The second byte is the high byte. */
		low  = 0; /* The first byte is the low byte. */
	}
	/* first: get length, check for errors -- stop at first one */
	for(i=0; i < l-1; i+=2)
	{
		unsigned long point = ((unsigned long) s[i+high]<<8) + s[i+low];
		if((point & 0xd800) == 0xd800) /* lead surrogate */
		{
			unsigned short second = (i+3 < l) ? (s[i+2+high]<<8) + s[i+2+low] : 0;
			if((second & 0xdc00) == 0xdc00) /* good... */
			{
				point = FULLPOINT(point,second);
				length += UTF8LEN(point); /* possibly 4 bytes */
				i+=2; /* We overstepped one word. */
			}
			else /* if no valid pair, break here */
			{
				debug1("Invalid UTF16 surrogate pair at %li.", (unsigned long)i);
				l = i; /* Forget the half pair, END! */
				break;
			}
		}
		else length += UTF8LEN(point); /* 1,2 or 3 bytes */
	}

	if(l < 1){ mpg123_set_string(sb, ""); return; }

	if(!mpg123_resize_string(sb, length+1)){ mpg123_free_string(sb); return ; }

	/* Now really convert, skip checks as these have been done just before. */
	p = (unsigned char*) sb->p; /* Signedness doesn't matter but it shows I thought about the non-issue */
	for(i=0; i < l-1; i+=2)
	{
		unsigned long codepoint = ((unsigned long) s[i+high]<<8) + s[i+low];
		if((codepoint & 0xd800) == 0xd800) /* lead surrogate */
		{
			unsigned short second = (s[i+2+high]<<8) + s[i+2+low];
			codepoint = FULLPOINT(codepoint,second);
			i+=2; /* We overstepped one word. */
		}
		if(codepoint < 0x80) *p++ = (unsigned char) codepoint;
		else if(codepoint < 0x800)
		{
			*p++ = 0xc0 | (codepoint>>6);
			*p++ = 0x80 | (codepoint & 0x3f);
		}
		else if(codepoint < 0x10000)
		{
			*p++ = 0xe0 | (codepoint>>12);
			*p++ = 0x80 | ((codepoint>>6) & 0x3f);
			*p++ = 0x80 | (codepoint & 0x3f);
		}
		else if (codepoint < 0x200000) 
		{
			*p++ = 0xf0 | codepoint>>18;
			*p++ = 0x80 | ((codepoint>>12) & 0x3f);
			*p++ = 0x80 | ((codepoint>>6) & 0x3f);
			*p++ = 0x80 | (codepoint & 0x3f);
		} /* ignore bigger ones (that are not possible here anyway) */
	}
	sb->p[sb->size-1] = 0; /* paranoia... */
	sb->fill = sb->size;
}
#undef UTF8LEN
#undef FULLPOINT

static void convert_utf16be(mpg123_string *sb, unsigned char* source, size_t len)
{
	convert_utf16(sb, source, len, 1);
}

static void convert_utf16bom(mpg123_string *sb, unsigned char* source, size_t len)
{
	if(len < 2){ mpg123_free_string(sb); return; }

	if(source[0] == 0xff && source[1] == 0xfe) /* Little-endian */
	convert_utf16(sb, source + 2, len - 2, 0);
	else /* Big-endian */
	convert_utf16(sb, source + 2, len - 2, 1);
}

static void convert_utf8(mpg123_string *sb, unsigned char* source, size_t len)
{
	if(mpg123_resize_string(sb, len+1))
	{
		memcpy(sb->p, source, len);
		sb->p[len] = 0;
		sb->fill = len+1;
	}
	else mpg123_free_string(sb);
}