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authorDan McGee <dan@archlinux.org>2011-09-28 00:37:27 +0200
committerDan McGee <dan@archlinux.org>2011-10-12 21:22:48 +0200
commita27bdcfe51e0c6eac30d8fbc5dcc2a67a1c1b929 (patch)
tree6cbd1ebd1a903e845abba9ab2452227ab17e5a3c
parent89fe19f3e102dae379c00e5b45dd1d42a6963962 (diff)
downloadpacman-a27bdcfe51e0c6eac30d8fbc5dcc2a67a1c1b929.tar.gz
pacman-a27bdcfe51e0c6eac30d8fbc5dcc2a67a1c1b929.tar.xz
_alpm_archive_fgets: optimize EOL search
Instead of iterating character by character, use memchr() calls to hopefully speed up the search. A newline is the most likely culprit, so search for that first followed by a NULL byte if there was no newline in the buffer. Signed-off-by: Dan McGee <dan@archlinux.org>
-rw-r--r--lib/libalpm/util.c34
1 files changed, 17 insertions, 17 deletions
diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c
index d723aee2..43f6cd52 100644
--- a/lib/libalpm/util.c
+++ b/lib/libalpm/util.c
@@ -918,16 +918,16 @@ int _alpm_test_checksum(const char *filepath, const char *expected,
/* Note: does NOT handle sparse files on purpose for speed. */
int _alpm_archive_fgets(struct archive *a, struct archive_read_buffer *b)
{
- char *i = NULL;
- int64_t offset;
- int done = 0;
-
/* ensure we start populating our line buffer at the beginning */
b->line_offset = b->line;
while(1) {
+ size_t block_remaining;
+ char *eol;
+
/* have we processed this entire block? */
if(b->block + b->block_size == b->block_offset) {
+ int64_t offset;
if(b->ret == ARCHIVE_EOF) {
/* reached end of archive on the last read, now we are out of data */
goto cleanup;
@@ -937,20 +937,20 @@ int _alpm_archive_fgets(struct archive *a, struct archive_read_buffer *b)
b->ret = archive_read_data_block(a, (void *)&b->block,
&b->block_size, &offset);
b->block_offset = b->block;
+ block_remaining = b->block_size;
/* error, cleanup */
if(b->ret < ARCHIVE_OK) {
goto cleanup;
}
+ } else {
+ block_remaining = b->block + b->block_size - b->block_offset;
}
- /* loop through the block looking for EOL characters */
- for(i = b->block_offset; i < (b->block + b->block_size); i++) {
- /* check if read value was null or newline */
- if(*i == '\0' || *i == '\n') {
- done = 1;
- break;
- }
+ /* look through the block looking for EOL characters */
+ eol = memchr(b->block_offset, '\n', block_remaining);
+ if(!eol) {
+ eol = memchr(b->block_offset, '\0', block_remaining);
}
/* allocate our buffer, or ensure our existing one is big enough */
@@ -960,8 +960,8 @@ int _alpm_archive_fgets(struct archive *a, struct archive_read_buffer *b)
b->line_size = b->block_size + 1;
b->line_offset = b->line;
} else {
- size_t needed = (size_t)((b->line_offset - b->line)
- + (i - b->block_offset) + 1);
+ size_t new = eol ? (eol - b->block_offset) : block_remaining;
+ size_t needed = (size_t)((b->line_offset - b->line) + new + 1);
if(needed > b->max_line_size) {
b->ret = -ERANGE;
goto cleanup;
@@ -978,11 +978,11 @@ int _alpm_archive_fgets(struct archive *a, struct archive_read_buffer *b)
}
}
- if(done) {
- size_t len = (size_t)(i - b->block_offset);
+ if(eol) {
+ size_t len = (size_t)(eol - b->block_offset);
memcpy(b->line_offset, b->block_offset, len);
b->line_offset[len] = '\0';
- b->block_offset = ++i;
+ b->block_offset = eol + 1;
/* this is the main return point; from here you can read b->line */
return ARCHIVE_OK;
} else {
@@ -990,7 +990,7 @@ int _alpm_archive_fgets(struct archive *a, struct archive_read_buffer *b)
size_t len = (size_t)(b->block + b->block_size - b->block_offset);
memcpy(b->line_offset, b->block_offset, len);
b->line_offset += len;
- b->block_offset = i;
+ b->block_offset = b->block + b->block_size;
/* there was no new data, return what is left; saved ARCHIVE_EOF will be
* returned on next call */
if(len == 0) {