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tag_ape: move code to ape.c

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Generic library for scanning APE tags.  Eliminated one "goto"!
This commit is contained in:
Max Kellermann
2010-11-18 21:44:24 +01:00
parent 8f46f1520c
commit 11613347be
4 changed files with 176 additions and 93 deletions
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112
src/tag_ape.c
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@@ -21,11 +21,7 @@
#include "tag_ape.h"
#include "tag.h"
#include "tag_table.h"
#include <glib.h>
#include <assert.h>
#include <stdio.h>
#include "ape.h"
static const char *const ape_tag_names[TAG_NUM_OF_ITEM_TYPES] = {
[TAG_ALBUM_ARTIST] = "album artist",
@@ -61,96 +57,26 @@ tag_ape_import_item(struct tag *tag, unsigned long flags,
return tag;
}
struct tag_ape_ctx {
struct tag *tag;
};
static bool
tag_ape_callback(unsigned long flags, const char *key,
const char *value, size_t value_length, void *_ctx)
{
struct tag_ape_ctx *ctx = _ctx;
ctx->tag = tag_ape_import_item(ctx->tag, flags, key,
value, value_length);
return true;
}
struct tag *
tag_ape_load(const char *file)
{
struct tag *ret = NULL;
FILE *fp;
int tagCount;
char *buffer = NULL;
char *p;
size_t tagLen;
size_t size;
unsigned long flags;
char *key;
struct tag_ape_ctx ctx = { .tag = NULL };
struct {
unsigned char id[8];
uint32_t version;
uint32_t length;
uint32_t tagCount;
unsigned char flags[4];
unsigned char reserved[8];
} footer;
fp = fopen(file, "rb");
if (!fp)
return NULL;
/* determine if file has an apeV2 tag */
if (fseek(fp, 0, SEEK_END))
goto fail;
size = (size_t)ftell(fp);
if (fseek(fp, size - sizeof(footer), SEEK_SET))
goto fail;
if (fread(&footer, 1, sizeof(footer), fp) != sizeof(footer))
goto fail;
if (memcmp(footer.id, "APETAGEX", sizeof(footer.id)) != 0)
goto fail;
if (GUINT32_FROM_LE(footer.version) != 2000)
goto fail;
/* find beginning of ape tag */
tagLen = GUINT32_FROM_LE(footer.length);
if (tagLen <= sizeof(footer) + 10)
goto fail;
if (tagLen > 1024 * 1024)
/* refuse to load more than one megabyte of tag data */
goto fail;
if (fseek(fp, size - tagLen, SEEK_SET))
goto fail;
/* read tag into buffer */
tagLen -= sizeof(footer);
assert(tagLen > 10);
buffer = g_malloc(tagLen);
if (fread(buffer, 1, tagLen, fp) != tagLen)
goto fail;
/* read tags */
tagCount = GUINT32_FROM_LE(footer.tagCount);
p = buffer;
while (tagCount-- && tagLen > 10) {
size = GUINT32_FROM_LE(*(const uint32_t *)p);
p += 4;
tagLen -= 4;
flags = GUINT32_FROM_LE(*(const uint32_t *)p);
p += 4;
tagLen -= 4;
/* get the key */
key = p;
while (tagLen > size && *p != '\0') {
p++;
tagLen--;
}
p++;
tagLen--;
/* get the value */
if (tagLen < size)
goto fail;
ret = tag_ape_import_item(ret, flags, key, p, size);
p += size;
tagLen -= size;
}
fail:
if (fp)
fclose(fp);
g_free(buffer);
return ret;
tag_ape_scan(file, tag_ape_callback, &ctx);
return ctx.tag;
}