Replace update_crc32 helper function with crc32 from zlib

It is optimized to the maximum and if we already use zlib anyway,
why not use zlib crc32? This also makes zlib a hard dependency which
also means the whole "do we have a compressor" sanity check in the
build system can be removed.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

4 files changed, 10 insertions, 39 deletions

diff --git a/lib/Makemodule.am b/lib/Makemodule.am
index 3c206d6..6301435 100644
--- a/lib/Makemodule.am
+++ b/lib/Makemodule.am
@@ -47,8 +47,10 @@ libutil_a_SOURCES += lib/util/read_data.c include/util.h
 libutil_a_SOURCES += lib/util/print_version.c lib/util/mkdir_p.c
 libutil_a_SOURCES += lib/util/str_table.c include/str_table.h
 libutil_a_SOURCES += lib/util/dirstack.c lib/util/padd_file.c
-libutil_a_SOURCES += lib/util/read_data_at.c lib/util/crc32.c
+libutil_a_SOURCES += lib/util/read_data_at.c
 libutil_a_SOURCES += lib/util/source_date_epoch.c
+libutil_a_CFLAGS = $(AM_CFLAGS)
+libutil_a_CPPFLAGS = $(AM_CPPFLAGS)
 
 if HAVE_PTHREAD
 libcompress_a_SOURCES += lib/comp/block_processor_parallel.c
@@ -62,6 +64,9 @@ libcompress_a_SOURCES += lib/comp/gzip.c
 
 libcompress_a_CFLAGS += $(ZLIB_CFLAGS)
 libcompress_a_CPPFLAGS += -DWITH_GZIP
+
+libutil_a_CFLAGS += $(ZLIB_CFLAGS)
+libutil_a_CPPFLAGS += -DWITH_GZIP
 endif
 
 if WITH_XZ
diff --git a/lib/comp/process_block.c b/lib/comp/process_block.c
index 76cd07d..0fcbae0 100644
--- a/lib/comp/process_block.c
+++ b/lib/comp/process_block.c
@@ -10,6 +10,7 @@
 #include "util.h"
 
 #include <string.h>
+#include <zlib.h>
 
 int process_block(block_t *block, compressor_t *cmp,
 		  uint8_t *scratch, size_t scratch_size)
@@ -17,7 +18,7 @@ int process_block(block_t *block, compressor_t *cmp,
 	ssize_t ret;
 
 	if (!(block->flags & BLK_DONT_CHECKSUM))
-		block->checksum = update_crc32(0, block->data, block->size);
+		block->checksum = crc32(0, block->data, block->size);
 
 	if (!(block->flags & BLK_DONT_COMPRESS)) {
 		ret = cmp->do_block(cmp, block->data, block->size,
diff --git a/lib/sqfs/data_writer.c b/lib/sqfs/data_writer.c
index 55c92ad..c584f1e 100644
--- a/lib/sqfs/data_writer.c
+++ b/lib/sqfs/data_writer.c
@@ -16,6 +16,7 @@
 #include <unistd.h>
 #include <stdio.h>
 #include <errno.h>
+#include <zlib.h>
 
 struct data_writer_t {
 	block_t *frag_block;
@@ -229,7 +230,7 @@ static int handle_fragment(data_writer_t *data, block_t *blk)
 {
 	file_info_t *fi = blk->user, *ref;
 
-	fi->fragment_chksum = update_crc32(0, blk->data, blk->size);
+	fi->fragment_chksum = crc32(0, blk->data, blk->size);
 
 	ref = fragment_by_chksum(fi, fi->fragment_chksum, blk->size,
 				 data->list, data->super->block_size);
diff --git a/lib/util/crc32.c b/lib/util/crc32.c
deleted file mode 100644
index 27c5b85..0000000
--- a/lib/util/crc32.c
+++ /dev/null
@@ -1,36 +0,0 @@
-/* SPDX-License-Identifier: GPL-3.0-or-later */
-/*
- * crc32.c
- *
- * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
- */
-#include "config.h"
-#include "util.h"
-
-/*
-  Karl Malbrain's compact CRC-32. See "A compact CCITT crc16 and crc32 C
-  implementation that balances processor cache usage against speed"
- */
-static const uint32_t s_crc32[16] = {
-	0x00000000, 0x1DB71064, 0x3B6E20C8, 0x26D930AC,
-	0x76DC4190, 0x6B6B51F4, 0x4DB26158, 0x5005713C,
-	0xEDB88320, 0xF00F9344, 0xD6D6A3E8, 0xCB61B38C,
-	0x9B64C2B0, 0x86D3D2D4, 0xA00AE278, 0xBDBDF21C
-};
-
-uint32_t update_crc32(uint32_t crc, const void *data, size_t size)
-{
-	const uint8_t *ptr = data;
-	uint8_t b;
-
-	crc = ~crc;
-
-	while (size--) {
-		b = *ptr++;
-
-		crc = (crc >> 4) ^ s_crc32[(crc & 0x0F) ^ (b & 0x0F)];
-		crc = (crc >> 4) ^ s_crc32[(crc & 0x0F) ^ (b >> 4)];
-	}
-
-	return ~crc;
-}