Convert v2.2 PIC to v2.4 APIC

* libid3tag/compat.gperf (translate_APIC): New function. Use it
to translate PIC to APIC.

1 files changed, 95 insertions, 2 deletions

diff --git a/libid3tag/compat.gperf b/libid3tag/compat.gperf
index 6fa1d4e..71e28d0 100644
--- a/libid3tag/compat.gperf
+++ b/libid3tag/compat.gperf
@@ -28,6 +28,7 @@
 
 # include <stdlib.h>
 # include <string.h>
+# include <ctype.h>
 
 # ifdef HAVE_ASSERT_H
 #  include <assert.h>
@@ -44,7 +45,7 @@
 # define OBSOLETE    0, 0
 # define TX(id)    #id, translate_##id
 
-static id3_compat_func_t translate_TCON;
+static id3_compat_func_t translate_TCON, translate_APIC;
 %}
 struct id3_compat;
 %%
@@ -72,7 +73,7 @@ IPLS, EQ(TIPL)  /* Involved people list */
 LNK,  EQ(LINK)  /* Linked information */
 MCI,  EQ(MCDI)  /* Music CD identifier */
 MLL,  EQ(MLLT)  /* MPEG location lookup table */
-PIC,  EQ(APIC)  /* Attached picture */
+PIC,  TX(APIC)  /* Attached picture */
 POP,  EQ(POPM)  /* Popularimeter */
 REV,  EQ(RVRB)  /* Reverb */
 RVA,  OBSOLETE  /* Relative volume adjustment [obsolete] */
@@ -190,6 +191,98 @@ translate_TCON(struct id3_frame *frame, char const *oldid,
 	return result;
 }
 
+static const char *
+translate_subtype(const id3_byte_t *in)
+{
+	static char lcin[4];
+	static struct inout {
+		char *in;
+		char *out;
+	} subtype_trans[] = {
+		{ "jpg", "jpeg" },
+		{ NULL }
+	};
+	struct inout *p;
+
+	lcin[0] = tolower(in[0]);
+	lcin[1] = tolower(in[1]);
+	lcin[2] = tolower(in[2]);
+	lcin[3] = 0;
+	for (p = subtype_trans; p->in; p++)
+		if (memcmp(p->in, in, 3) == 0)
+			return p->out;
+	return lcin;
+}
+
+static id3_latin1_t *
+str_to_mime_type(const id3_byte_t *str)
+{
+	const char *subtype = translate_subtype(str);
+	static const char prefix[] = "image/";
+	char *ret;
+
+	ret = malloc(sizeof(prefix) + strlen(subtype));
+	if (ret)
+		strcat(strcpy(ret, prefix), subtype);
+	return (id3_latin1_t *) ret;
+}
+
+static int
+translate_APIC(struct id3_frame *frame, char const *oldid,
+	       id3_byte_t const *data, id3_length_t length)
+{
+	id3_byte_t const *end;
+	enum id3_field_textencoding encoding =
+		ID3_FIELD_TEXTENCODING_ISO_8859_1;
+	int rc = 0;
+
+	/* translate old PIC into APIC */
+
+	assert(frame->nfields == 5);
+
+	end = data + length;
+
+	do {
+		/* Encoding */
+		if ((rc = id3_field_parse(&frame->fields[0], &data,
+					  end - data, &encoding)) == -1)
+			break;
+
+                /* MIME type: a 3-byte string in v2.2, as pointed out
+		   in https://bugs.kde.org/show_bug.cgi?id=167786#c2 */
+		if ((end - data) < 3) {
+			rc = -1;
+			break;
+		}
+		id3_field_finish(&frame->fields[1]);
+		frame->fields[1].latin1.ptr = str_to_mime_type(data);
+		if (!frame->fields[1].latin1.ptr) {
+			rc = -1;
+			break;
+		}
+		data += 3;
+		
+		/* Picture type */
+		if ((rc = id3_field_parse(&frame->fields[2], &data,
+					  end - data, &encoding)) == -1)
+			break;
+		/* Description */
+		if ((rc = id3_field_parse(&frame->fields[3], &data,
+					  end - data, &encoding)) == -1)
+			break;
+		/* Picture date */
+		if ((rc = id3_field_parse(&frame->fields[4], &data,
+					  end - data, &encoding)) == -1)
+			break;
+	} while (0);
+
+	if (rc) {
+		/* FIXME: cleanup */
+		;
+	}
+	return rc;
+}
+
 /*
  * NAME:	compat->fixup()
  * DESCRIPTION:	finish compatibility translations