shithub: libtags

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add opus support

--- a/README.md

+++ b/README.md

@@ -11,6 +11,7 @@

 | Ogg/Vorbis     | yes             | no               | yes              |

 | FLAC           | yes             | no               | yes              |

 | m4a            | yes             | no               | yes              |

+| opus           | yes             | no               | yes              |

 | replay gain    | yes             | no               | ???              |

 | size           | tiny            | bloated          | more bloated     |

 | license        | PPL             | LGPL             | LGPL/MPL         |

--- a/mkfile

+++ b/mkfile

@@ -8,6 +8,7 @@

 	id3v1.$O\

 	id3v2.$O\

 	m4a.$O\

+	opus.$O\

 	tags.$O\

 	utf16.$O\

 	vorbis.$O\

--- /dev/null

+++ b/opus.c

@@ -1,0 +1,93 @@

+#include "tagspriv.h"

+

+#define leuint(d) (uint)(((uchar*)(d))[3]<<24 | ((uchar*)(d))[2]<<16 | ((uchar*)(d))[1]<<8 | ((uchar*)(d))[0]<<0)

+

+int

+tagopus(Tagctx *ctx)

+{

+	char *v;

+	uchar *d, h[4];

+	int sz, numtags, i, npages;

+

+	d = (uchar*)ctx->buf;

+	/* need to find vorbis frame with type=3 */

+	for(npages = 0; npages < 2; npages++){ /* vorbis comment is the second header */

+		int nsegs;

+		if(ctx->read(ctx, d, 27) != 27)

+			return -1;

+		if(memcmp(d, "OggS", 4) != 0)

+			return -1;

+

+		/* calculate the size of the packet */

+		nsegs = d[26];

+		if(ctx->read(ctx, d, nsegs+8) != nsegs+8)

+			return -1;

+		for(sz = i = 0; i < nsegs; sz += d[i++]);

+

+		if(memcmp(&d[nsegs], "OpusHead", 8) == 0){

+			if(ctx->read(ctx, d, 8) != 8 || d[0] != 1)

+				return -1;

+			sz -= 8;

+			ctx->channels = d[1];

+			ctx->samplerate = leuint(&d[4]);

+		}else if(memcmp(&d[nsegs], "OpusTags", 8) == 0){

+			break;

+		}

+

+		ctx->seek(ctx, sz-8, 1);

+	}

+

+	if(npages < 3){

+		if(ctx->read(ctx, d, 4) != 4)

+			return -1;

+		sz = leuint(d);

+		if(ctx->seek(ctx, sz, 1) < 0 || ctx->read(ctx, h, 4) != 4)

+			return -1;

+		numtags = leuint(h);

+

+		for(i = 0; i < numtags; i++){

+			if(ctx->read(ctx, h, 4) != 4)

+				return -1;

+			if((sz = leuint(h)) < 0)

+				return -1;

+

+			if(ctx->bufsz < sz+1){

+				if(ctx->seek(ctx, sz, 1) < 0)

+					return -1;

+				continue;

+			}

+			if(ctx->read(ctx, ctx->buf, sz) != sz)

+				return -1;

+			ctx->buf[sz] = 0;

+

+			if((v = strchr(ctx->buf, '=')) == nil)

+				return -1;

+			*v++ = 0;

+			cbvorbiscomment(ctx, ctx->buf, v);

+		}

+	}

+

+	/* calculate the duration */

+	if(ctx->samplerate > 0){

+		sz = ctx->bufsz <= 4096 ? ctx->bufsz : 4096;

+		for(i = sz; i < 65536+16; i += sz - 16){

+			if(ctx->seek(ctx, -i, 2) <= 0)

+				break;

+			v = ctx->buf;

+			if(ctx->read(ctx, v, sz) != sz)

+				break;

+			for(; v != nil && v < ctx->buf+sz;){

+				v = memchr(v, 'O', ctx->buf+sz - v - 14);

+				if(v != nil && v[1] == 'g' && v[2] == 'g' && v[3] == 'S' && (v[5] & 4) == 4){ /* last page */

+					uvlong g = leuint(v+6) | (uvlong)leuint(v+10)<<32;

+					ctx->duration = g * 1000 / ctx->samplerate;

+					return 0;

+				}

+				if(v != nil)

+					v++;

+			}

+		}

+	}

+

+	return 0;

+}

--- a/tags.c

+++ b/tags.c

@@ -13,6 +13,7 @@

 extern int tagid3v2(Tagctx *ctx);

 extern int tagid3v1(Tagctx *ctx);

 extern int tagm4a(Tagctx *ctx);

+extern int tagopus(Tagctx *ctx);

 static const Getter g[] =

 {

@@ -21,6 +22,7 @@

 	{tagvorbis, Fogg},

 	{tagflac, Fflac},

 	{tagm4a, Fm4a},

+	{tagopus, Fopus},

 };

 void

--- a/tags.h

+++ b/tags.h

@@ -30,6 +30,7 @@

 	Fogg,

 	Fflac,

 	Fm4a,

+	Fopus,

 };

 /* Tag parser context. You need to set it properly before parsing an audio file using libtags. */