libbb: commonalize a bit of little-endian CRC32 table generation code

function                                             old     new   delta
global_crc32_new_table_le                              -      11     +11
crc32_new_table_le                                     -       9      +9
inflate_unzip_internal                               560     556      -4
flash_eraseall_main                                  823     819      -4
unpack_xz_stream                                    2403    2394      -9
lzop_main                                            121     112      -9
gzip_main                                            187     178      -9
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 0/5 up/down: 20/-35)            Total: -15 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

8 files changed, 18 insertions, 6 deletions

diff --git a/archival/gzip.c b/archival/gzip.c
index e3dd79291..c5a1fe9b4 100644
--- a/archival/gzip.c
+++ b/archival/gzip.c
@@ -2239,7 +2239,7 @@ int gzip_main(int argc UNUSED_PARAM, char **argv)
 	ALLOC(ush, G1.prev, 1L << BITS);
 
 	/* Initialize the CRC32 table */
-	global_crc32_table = crc32_filltable(NULL, 0);
+	global_crc32_new_table_le();
 
 	argv += optind;
 	return bbunpack(argv, pack_gzip, append_ext, "gz");
diff --git a/archival/libarchive/decompress_gunzip.c b/archival/libarchive/decompress_gunzip.c
index c8245d736..edff7e0e5 100644
--- a/archival/libarchive/decompress_gunzip.c
+++ b/archival/libarchive/decompress_gunzip.c
@@ -1000,7 +1000,7 @@ inflate_unzip_internal(STATE_PARAM transformer_state_t *xstate)
 	gunzip_bb = 0;
 
 	/* Create the crc table */
-	gunzip_crc_table = crc32_filltable(NULL, 0);
+	gunzip_crc_table = crc32_new_table_le();
 	gunzip_crc = ~0;
 
 	error_msg = "corrupted data";
diff --git a/archival/libarchive/decompress_unxz.c b/archival/libarchive/decompress_unxz.c
index 0be85500c..8ae7a275b 100644
--- a/archival/libarchive/decompress_unxz.c
+++ b/archival/libarchive/decompress_unxz.c
@@ -52,7 +52,7 @@ unpack_xz_stream(transformer_state_t *xstate)
 	IF_DESKTOP(long long) int total = 0;
 
 	if (!global_crc32_table)
-		global_crc32_table = crc32_filltable(NULL, /*endian:*/ 0);
+		global_crc32_new_table_le();
 
 	memset(&iobuf, 0, sizeof(iobuf));
 	membuf = xmalloc(2 * BUFSIZ);
diff --git a/archival/lzop.c b/archival/lzop.c
index ba27aeff0..fef8cdba3 100644
--- a/archival/lzop.c
+++ b/archival/lzop.c
@@ -1148,6 +1148,6 @@ int lzop_main(int argc UNUSED_PARAM, char **argv)
 	if (ENABLE_UNLZOP && applet_name[4] == 'o')
 		option_mask32 |= OPT_DECOMPRESS;
 
-	global_crc32_table = crc32_filltable(NULL, 0);
+	global_crc32_new_table_le();
 	return bbunpack(argv, pack_lzop, make_new_name_lzop, /*unused:*/ NULL);
 }
diff --git a/include/libbb.h b/include/libbb.h
index a93864020..2bb364366 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1928,6 +1928,8 @@ typedef struct md5_ctx_t md5sha_ctx_t;
 
 extern uint32_t *global_crc32_table;
 uint32_t *crc32_filltable(uint32_t *tbl256, int endian) FAST_FUNC;
+uint32_t *crc32_new_table_le(void) FAST_FUNC;
+uint32_t *global_crc32_new_table_le(void) FAST_FUNC;
 uint32_t crc32_block_endian1(uint32_t val, const void *buf, unsigned len, uint32_t *crc_table) FAST_FUNC;
 uint32_t crc32_block_endian0(uint32_t val, const void *buf, unsigned len, uint32_t *crc_table) FAST_FUNC;
 
diff --git a/libbb/crc32.c b/libbb/crc32.c
index b00b580d0..728bcb736 100644
--- a/libbb/crc32.c
+++ b/libbb/crc32.c
@@ -41,6 +41,16 @@ uint32_t* FAST_FUNC crc32_filltable(uint32_t *crc_table, int endian)
 
 	return crc_table - 256;
 }
+/* Common uses: */
+uint32_t* FAST_FUNC crc32_new_table_le(void)
+{
+	return crc32_filltable(NULL, 0);
+}
+uint32_t* FAST_FUNC global_crc32_new_table_le(void)
+{
+	global_crc32_table = crc32_new_table_le();
+	return global_crc32_table;
+}
 
 uint32_t FAST_FUNC crc32_block_endian1(uint32_t val, const void *buf, unsigned len, uint32_t *crc_table)
 {
diff --git a/miscutils/flash_eraseall.c b/miscutils/flash_eraseall.c
index fab21291c..8e93060ca 100644
--- a/miscutils/flash_eraseall.c
+++ b/miscutils/flash_eraseall.c
@@ -101,7 +101,7 @@ int flash_eraseall_main(int argc UNUSED_PARAM, char **argv)
 	if (flags & OPTION_J) {
 		uint32_t *crc32_table;
 
-		crc32_table = crc32_filltable(NULL, 0);
+		crc32_table = crc32_new_table_le();
 
 		cleanmarker.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 		cleanmarker.nodetype = cpu_to_je16(JFFS2_NODETYPE_CLEANMARKER);
diff --git a/util-linux/fdisk_gpt.c b/util-linux/fdisk_gpt.c
index 45d2aa6e7..cdb90627d 100644
--- a/util-linux/fdisk_gpt.c
+++ b/util-linux/fdisk_gpt.c
@@ -177,7 +177,7 @@ check_gpt_label(void)
 
 	init_unicode();
 	if (!global_crc32_table) {
-		global_crc32_table = crc32_filltable(NULL, 0);
+		global_crc32_new_table_le();
 	}
 
 	crc = SWAP_LE32(gpt_hdr->hdr_crc32);