libbb: introduce and use common crc32 routine

function                                             old     new   delta
crc32_block_endian1                                    -      37     +37
crc32_block_endian0                                    -      34     +34
global_crc32_table                                     -       8      +8
file_read                                             82      87      +5
gzip_main                                            211     214      +3
xz_crc32                                              40      35      -5
crc32_table                                            8       -      -8
calculate_gunzip_crc                                  54      34     -20
lzo_crc32                                             54      25     -29
cksum_main                                           298     211     -87
------------------------------------------------------------------------------
(add/remove: 3/1 grow/shrink: 2/4 up/down: 87/-149)           Total: -62 bytes

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

2 files changed, 4 insertions, 15 deletions

diff --git a/archival/libunarchive/decompress_unxz.c b/archival/libunarchive/decompress_unxz.c
index faba9ca82..ca427231e 100644
--- a/archival/libunarchive/decompress_unxz.c
+++ b/archival/libunarchive/decompress_unxz.c
@@ -22,17 +22,9 @@
 
 /* We use our own crc32 function */
 #define XZ_INTERNAL_CRC32 0
-static uint32_t *crc32_table;
 static uint32_t xz_crc32(const uint8_t *buf, size_t size, uint32_t crc)
 {
-        crc = ~crc;
-
-        while (size != 0) {
-                crc = crc32_table[*buf++ ^ (crc & 0xFF)] ^ (crc >> 8);
-                --size;
-        }
-
-        return ~crc;
+        return ~crc32_block_endian0(~crc, buf, size, global_crc32_table);
 }
 
 /* We use arch-optimized unaligned accessors */
@@ -53,8 +45,8 @@ unpack_xz_stream(int src_fd, int dst_fd)
         unsigned char *membuf;
         IF_DESKTOP(long long) int total = 0;
 
-        if (!crc32_table)
-                crc32_table = crc32_filltable(NULL, /*endian:*/ 0);
+        if (!global_crc32_table)
+                global_crc32_table = crc32_filltable(NULL, /*endian:*/ 0);
 
         memset(&iobuf, 0, sizeof(iobuf));
         /* Preload XZ file signature */
diff --git a/archival/libunarchive/decompress_unzip.c b/archival/libunarchive/decompress_unzip.c
index 20fda9d26..cb8a3d737 100644
--- a/archival/libunarchive/decompress_unzip.c
+++ b/archival/libunarchive/decompress_unzip.c
@@ -925,10 +925,7 @@ static int inflate_block(STATE_PARAM smallint *e)
 /* Two callsites, both in inflate_get_next_window */
 static void calculate_gunzip_crc(STATE_PARAM_ONLY)
 {
-        unsigned n;
-        for (n = 0; n < gunzip_outbuf_count; n++) {
-                gunzip_crc = gunzip_crc_table[((int) gunzip_crc ^ (gunzip_window[n])) & 0xff] ^ (gunzip_crc >> 8);
-        }
+        gunzip_crc = crc32_block_endian0(gunzip_crc, gunzip_window, gunzip_outbuf_count, gunzip_crc_table);
         gunzip_bytes_out += gunzip_outbuf_count;
 }