Patch from Rob Sullivan to consolidate crc32 table generation.

6 files changed, 65 insertions, 71 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)
diff --git a/archival/libunarchive/decompress_bunzip2.c b/archival/libunarchive/decompress_bunzip2.c
index 3d07d9e03..1879f7255 100644
--- a/archival/libunarchive/decompress_bunzip2.c
+++ b/archival/libunarchive/decompress_bunzip2.c
@@ -84,8 +84,8 @@ typedef struct {
 
         /* The CRC values stored in the block header and calculated from the data */
 
-        unsigned int crc32Table[256],headerCRC, totalCRC, writeCRC;
-
+        uint32_t headerCRC, totalCRC, writeCRC;
+        uint32_t *crc32Table;
         /* Intermediate buffer and its size (in bytes) */
 
         unsigned int *dbuf, dbufSize;
@@ -620,7 +620,7 @@ decode_next_byte:
                 bd->writeCount=previous;
                 return (previous!=RETVAL_LAST_BLOCK) ? previous : gotcount;
         }
-        bd->writeCRC=0xffffffffUL;
+        bd->writeCRC=~0;
         pos=bd->writePos;
         current=bd->writeCurrent;
         goto decode_next_byte;
@@ -634,7 +634,7 @@ static int start_bunzip(bunzip_data **bdp, int in_fd, unsigned char *inbuf,
                                                 int len)
 {
         bunzip_data *bd;
-        unsigned int i,j,c;
+        unsigned int i;
         const unsigned int BZh0=(((unsigned int)'B')<<24)+(((unsigned int)'Z')<<16)
                                                         +(((unsigned int)'h')<<8)+(unsigned int)'0';
 
@@ -657,12 +657,7 @@ static int start_bunzip(bunzip_data **bdp, int in_fd, unsigned char *inbuf,
 
         /* Init the CRC32 table (big endian) */
 
-        for(i=0;i<256;i++) {
-                c=i<<24;
-                for(j=8;j;j--)
-                        c=c&0x80000000 ? (c<<1)^0x04c11db7 : (c<<1);
-                bd->crc32Table[i]=c;
-        }
+        bd->crc32Table = bb_crc32_filltable(1);
 
         /* Setup for I/O error handling via longjmp */
 
diff --git a/archival/libunarchive/decompress_unzip.c b/archival/libunarchive/decompress_unzip.c
index 3215697aa..a589bdcd4 100644
--- a/archival/libunarchive/decompress_unzip.c
+++ b/archival/libunarchive/decompress_unzip.c
@@ -95,8 +95,8 @@ static unsigned int gunzip_outbuf_count;	/* bytes in output buffer */
 enum { gunzip_wsize = 0x8000 };
 static unsigned char *gunzip_window;
 
-static unsigned int *gunzip_crc_table;
-unsigned int gunzip_crc;
+static uint32_t *gunzip_crc_table;
+uint32_t gunzip_crc;
 
 /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
 #define BMAX 16 /* maximum bit length of any code (16 for explode) */
@@ -168,35 +168,6 @@ static unsigned int fill_bitbuffer(unsigned int bitbuffer, unsigned int *current
         return(bitbuffer);
 }
 
-static void make_gunzip_crc_table(void)
-{
-        const unsigned int poly = 0xedb88320;   /* polynomial exclusive-or pattern */
-        unsigned short i;       /* counter for all possible eight bit values */
-
-        /* initial shift register value */
-        gunzip_crc = 0xffffffffL;
-        gunzip_crc_table = (unsigned int *) xmalloc(256 * sizeof(unsigned int));
-
-        /* Compute and print table of CRC's, five per line */
-        for (i = 0; i < 256; i++) {
-                unsigned int table_entry;       /* crc shift register */
-                unsigned char k;        /* byte being shifted into crc apparatus */
-
-                table_entry = 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--) {
-                        if (table_entry & 1) {
-                                table_entry = (table_entry >> 1) ^ poly;
-                        } else {
-                                table_entry >>= 1;
-                        }
-                }
-                gunzip_crc_table[i] = table_entry;
-        }
-}
-
 /*
  * Free the malloc'ed tables built by huft_build(), which makes a linked
  * list of the tables it made, with the links in a dummy first entry of
@@ -922,8 +893,9 @@ int inflate_unzip(int in, int out)
         gunzip_bb = 0;
 
         /* Create the crc table */
-        make_gunzip_crc_table();
-
+        gunzip_crc_table = bb_crc32_filltable(0);
+        gunzip_crc = ~0;
+        
         /* Allocate space for buffer */
         bytebuffer = xmalloc(bytebuffer_max);
 
@@ -955,7 +927,7 @@ int inflate_unzip(int in, int out)
 
 int inflate_gunzip(int in, int out)
 {
-        unsigned int stored_crc = 0;
+        uint32_t stored_crc = 0;
         unsigned int count;
 
         inflate_unzip(in, out);
@@ -972,7 +944,7 @@ int inflate_gunzip(int in, int out)
         }
 
         /* Validate decompression - crc */
-        if (stored_crc != (gunzip_crc ^ 0xffffffffL)) {
+        if (stored_crc != (~gunzip_crc)) {
                 bb_error_msg("crc error");
                 return -1;
         }
diff --git a/include/libbb.h b/include/libbb.h
index 64a235a9f..edbc58206 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -508,6 +508,8 @@ void md5_begin(md5_ctx_t *ctx);
 void md5_hash(const void *data, size_t length, md5_ctx_t *ctx);
 void *md5_end(void *resbuf, md5_ctx_t *ctx);
 
+extern uint32_t *bb_crc32_filltable (int endian);
+
 /* busybox.h will include dmalloc later for us, else include it here.  */
 #if !defined _BB_INTERNAL_H_ && defined DMALLOC
 #include <dmalloc.h>
diff --git a/libbb/Makefile.in b/libbb/Makefile.in
index 338a5be97..2d9a1745d 100644
--- a/libbb/Makefile.in
+++ b/libbb/Makefile.in
@@ -13,7 +13,7 @@ LIBBB-n:=
 LIBBB-y:= \
         bb_asprintf.c ask_confirmation.c change_identity.c chomp.c \
         compare_string_array.c concat_path_file.c copy_file.c copyfd.c \
-        create_icmp_socket.c create_icmp6_socket.c \
+        crc32.c create_icmp_socket.c create_icmp6_socket.c \
         device_open.c dump.c error_msg.c error_msg_and_die.c find_mount_point.c \
         find_pid_by_name.c find_root_device.c fgets_str.c full_read.c \
         full_write.c get_last_path_component.c get_line_from_file.c \
diff --git a/libbb/crc32.c b/libbb/crc32.c
new file mode 100644
index 000000000..03609952d
--- /dev/null
+++ b/libbb/crc32.c
@@ -0,0 +1,40 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * CRC32 table fill function
+ * Copyright (C) 2006 by Rob Sullivan <cogito.ergo.cogito@gmail.com>
+ * (I can't really claim much credit however, as the algorithm is
+ * very well-known)
+ *
+ * The following function creates a CRC32 table depending on whether
+ * a big-endian (0x04c11db7) or little-endian (0xedb88320) CRC32 is 
+ * required. Admittedly, there are other CRC32 polynomials floating
+ * around, but Busybox doesn't use them.
+ *
+ * endian = 1: big-endian
+ * endian = 0: little-endian
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include "libbb.h"
+
+uint32_t *bb_crc32_filltable (int endian) {
+        
+        uint32_t *crc_table = xmalloc(256 * sizeof(uint32_t));
+        uint32_t polynomial = endian ? 0x04c11db7 : 0xedb88320;
+        uint32_t c;
+        int i, j;
+        
+        for (i = 0; i < 256; i++) {
+                c = endian ? (i << 24) : i;
+                for (j = 8; j; j--) {
+                        if (endian)
+                                c = (c&0x80000000) ? ((c << 1) ^ polynomial) : (c << 1);
+                        else
+                                c = (c&1) ? ((c >> 1) ^ polynomial) : (c >> 1);
+                }
+                *crc_table++ = c;
+        }
+
+        return crc_table - 256;
+}