tag/Id3Load: don't seek twice in tag_id3_read()

Copy the query buffer to the allocated buffer, and read only the
remaining data.
This commit is contained in:
Max Kellermann 2016-02-19 19:42:44 +01:00
parent 2ef8403bfa
commit 84fe3bfa87

View File

@ -30,6 +30,8 @@
#include <id3tag.h>
#include <algorithm>
#include <stdio.h>
static constexpr Domain id3_domain("id3");
@ -77,12 +79,19 @@ tag_id3_read(FILE *stream, long offset, int whence)
return UniqueId3Tag(id3_tag_parse(query_buffer, tag_size));
std::unique_ptr<id3_byte_t[]> tag_buffer(new id3_byte_t[tag_size]);
int tag_buffer_size = fill_buffer(tag_buffer.get(), tag_size,
stream, offset, whence);
if (tag_buffer_size < tag_size)
/* copy the start of the tag we already have to the allocated
buffer */
id3_byte_t *end = std::copy_n(query_buffer, query_buffer_size,
tag_buffer.get());
/* now read the remaining bytes */
const size_t remaining = tag_size - query_buffer_size;
const size_t nbytes = fread(end, 1, remaining, stream);
if (nbytes != remaining)
return nullptr;
return UniqueId3Tag(id3_tag_parse(tag_buffer.get(), tag_buffer_size));
return UniqueId3Tag(id3_tag_parse(tag_buffer.get(), tag_size));
}
static UniqueId3Tag