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)
* 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)
} while (--n);
}
crc = c;
- return c ^ 0xffffffffL; /* (instead of ~c for 64-bit machines) */
+ return ~c;
}
/* bits.c -- output variable-length bit strings
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;
*/
-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)
/* 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;
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;
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';
/* 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 */
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) */
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
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);
int inflate_gunzip(int in, int out)
{
- unsigned int stored_crc = 0;
+ uint32_t stored_crc = 0;
unsigned int count;
inflate_unzip(in, out);
}
/* Validate decompression - crc */
- if (stored_crc != (gunzip_crc ^ 0xffffffffL)) {
+ if (stored_crc != (~gunzip_crc)) {
bb_error_msg("crc error");
return -1;
}
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>
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 \
--- /dev/null
+/* 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;
+}
projects / oweals / busybox.git / commitdiff