Patch from Rob Sullivan to consolidate crc32 table generation.

1 files changed, 10 insertions, 25 deletions

diff --git a/archival/gzip.c b/archival/gzip.c
index fa6e85b66..41ed3a2c7 100644
--- a/archival/gzip.c
+++ b/archival/gzip.c
@@ -293,6 +293,7 @@ static int ofd;			/* output file descriptor */
 static unsigned insize; /* valid bytes in inbuf */
 static unsigned outcnt; /* bytes in output buffer */
 
+static uint32_t *crc_32_tab;
 
 /* Output a 16 bit value, lsb first */
 static void put_short(ush w)
@@ -344,32 +345,13 @@ static void write_buf(int fd, void *buf, unsigned cnt)
  * pointer, then initialize the crc shift register contents instead.
  * Return the current crc in either case.
  */
-static ulg updcrc(uch * s, unsigned n)
+static uint32_t updcrc(uch * s, unsigned n)
 {
-        static ulg crc = (ulg) 0xffffffffL;     /* shift register contents */
-        register ulg c;         /* temporary variable */
-        static unsigned long crc_32_tab[256];
-
-        if (crc_32_tab[1] == 0x00000000L) {
-                unsigned long csr;      /* crc shift register */
-                const unsigned long e = 0xedb88320L;    /* polynomial exclusive-or pattern */
-                int i;                  /* counter for all possible eight bit values */
-                int k;                  /* byte being shifted into crc apparatus */
-
-                /* Compute table of CRC's. */
-                for (i = 1; i < 256; i++) {
-                        csr = i;
-                        /* The idea to initialize the register with the byte instead of
-                           * zero was stolen from Haruhiko Okumura's ar002
-                         */
-                        for (k = 8; k; k--)
-                                csr = csr & 1 ? (csr >> 1) ^ e : csr >> 1;
-                        crc_32_tab[i] = csr;
-                }
-        }
+        static uint32_t crc = ~0;       /* shift register contents */
+        uint32_t c;             /* temporary variable */
 
         if (s == NULL) {
-                c = 0xffffffffL;
+                c = ~0;
         } else {
                 c = crc;
                 if (n)
@@ -378,7 +360,7 @@ static ulg updcrc(uch * s, unsigned n)
                         } while (--n);
         }
         crc = c;
-        return c ^ 0xffffffffL; /* (instead of ~c for 64-bit machines) */
+        return ~c;
 }
 
 /* bits.c -- output variable-length bit strings
@@ -1223,6 +1205,9 @@ int gzip_main(int argc, char **argv)
         ALLOC(uch, window, 2L * WSIZE);
         ALLOC(ush, tab_prefix, 1L << BITS);
 
+        /* Initialise the CRC32 table */
+        crc_32_tab = bb_crc32_filltable(0);
+        
         clear_bufs();
         part_nb = 0;
 
@@ -2416,7 +2401,7 @@ static void set_file_type(void)
  */
 
 
-static ulg crc;                 /* crc on uncompressed file data */
+static uint32_t crc;                    /* crc on uncompressed file data */
 static long header_bytes;       /* number of bytes in gzip header */
 
 static void put_long(ulg n)