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metadata: mp3: Reduce size of is_cuesheet function

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Saves 80 bytes on Sansa E200V2 (176 -> 96)

Change-Id: I976e47f74641110ef37049101b9eb0db0afe512b
This commit is contained in:
Roman Artiukhin 2024-12-13 12:09:20 +02:00
parent 23d185b7fe
commit 11fbbc7826
1 changed files with 22 additions and 27 deletions
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49
lib/rbcodec/metadata/id3tags.c
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@ -725,54 +725,49 @@ bool setid3v1title(int fd, struct mp3entry *entry)
static bool is_cuesheet(char *tag, unsigned char *char_enc, unsigned char *cuesheet_offset)
{
*char_enc = 0;
*char_enc = CHAR_ENC_ISO_8859_1;
/* [enc type]+"CUESHEET\0" = 10 */
*cuesheet_offset = 10;
unsigned char utf16 = 0;
switch (tag[0])
const char* key = "CUESHEET";
const int key_size = 8;
// check and skip encoding type
switch (*(tag++))
{
case 0x00:
*char_enc = CHAR_ENC_ISO_8859_1;
break;
case 0x01:
if (!memcmp(tag + 1, BOM_UTF_16_BE, BOM_UTF_16_SIZE))
utf16 = CHAR_ENC_UTF_16_BE;
else if (!memcmp(tag + 1, BOM_UTF_16_LE, BOM_UTF_16_SIZE))
utf16 = CHAR_ENC_UTF_16_LE;
if (!memcmp(tag, BOM_UTF_16_BE, BOM_UTF_16_SIZE))
*char_enc = CHAR_ENC_UTF_16_BE;
else if (!memcmp(tag, BOM_UTF_16_LE, BOM_UTF_16_SIZE))
*char_enc = CHAR_ENC_UTF_16_LE;
else
return false;
tag+= BOM_UTF_16_SIZE;
*char_enc = utf16;
/* \1 + BOM(2) + C0U0E0S0H0E0E0T000 = 21 */
*cuesheet_offset = 21;
break;
case 0x02:
utf16 = *char_enc = CHAR_ENC_UTF_16_BE;
*char_enc = CHAR_ENC_UTF_16_BE;
/* \2 + 0C0U0E0S0H0E0E0T00 = 19 */
*cuesheet_offset = 19;
break;
case 0x03:
*char_enc = CHAR_ENC_UTF_8;
break;
//fallthrough
case 0x00:
return !strncmp(tag, key, key_size);
default:
return false;
}
++tag; //skip encoding type
const char* key = "CUESHEET";
if (!utf16)
return !strncmp(tag, key, 8);
int tag_index;
for (int i =0; i < 8; ++i)
// check if UTF-16 string is variation of C0U0E0S0H0E0E0T or 0C0U0E0S0H0E0E0T
for (int i =0; i < key_size; ++i)
{
tag_index = i<<1;
if ( (utf16 == CHAR_ENC_UTF_16_BE && tag[tag_index] == 0 && tag[tag_index + 1] == key[i] )
|| (tag[tag_index] == key[i] && tag[tag_index + 1] == 0 ))
continue;
return false;
const char* utf16_char = &tag[(i << 1)];
if (*utf16_char + *(utf16_char + 1) != key[i])
return false;
}
return true;
}
@ -1093,7 +1088,7 @@ retry_with_limit:
aren't binary */
if(!tr->binary) {
if ( /* Is it an embedded cuesheet? */
(tr->offset == 0 && tr->tag_length == 4 && !memcmp(header, "TXXX", 4)) &&
(ptag == NULL && tr->tag_length == 4 && !memcmp(header, "TXXX", 4)) &&
(bytesread >= 14)
) {
unsigned char char_enc;