From a27bdcfe51e0c6eac30d8fbc5dcc2a67a1c1b929 Mon Sep 17 00:00:00 2001 From: Dan McGee Date: Tue, 27 Sep 2011 17:37:27 -0500 Subject: _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 --- lib/libalpm/util.c | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) (limited to 'lib') 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) { -- cgit v1.2.3-24-g4f1b