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Patch from Rob Sullivan to consolidate crc32 table generation.
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@ -293,6 +293,7 @@ static int ofd; /* output file descriptor */
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static unsigned insize; /* valid bytes in inbuf */
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static unsigned outcnt; /* bytes in output buffer */
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static uint32_t *crc_32_tab;
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/* Output a 16 bit value, lsb first */
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static void put_short(ush w)
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@ -344,32 +345,13 @@ static void write_buf(int fd, void *buf, unsigned cnt)
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* pointer, then initialize the crc shift register contents instead.
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* Return the current crc in either case.
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*/
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static ulg updcrc(uch * s, unsigned n)
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static uint32_t updcrc(uch * s, unsigned n)
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{
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static ulg crc = (ulg) 0xffffffffL; /* shift register contents */
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register ulg c; /* temporary variable */
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static unsigned long crc_32_tab[256];
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if (crc_32_tab[1] == 0x00000000L) {
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unsigned long csr; /* crc shift register */
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const unsigned long e = 0xedb88320L; /* polynomial exclusive-or pattern */
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int i; /* counter for all possible eight bit values */
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int k; /* byte being shifted into crc apparatus */
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/* Compute table of CRC's. */
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for (i = 1; i < 256; i++) {
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csr = i;
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/* The idea to initialize the register with the byte instead of
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* zero was stolen from Haruhiko Okumura's ar002
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*/
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for (k = 8; k; k--)
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csr = csr & 1 ? (csr >> 1) ^ e : csr >> 1;
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crc_32_tab[i] = csr;
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}
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}
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static uint32_t crc = ~0; /* shift register contents */
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uint32_t c; /* temporary variable */
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if (s == NULL) {
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c = 0xffffffffL;
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c = ~0;
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} else {
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c = crc;
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if (n)
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@ -378,7 +360,7 @@ static ulg updcrc(uch * s, unsigned n)
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} while (--n);
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}
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crc = c;
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return c ^ 0xffffffffL; /* (instead of ~c for 64-bit machines) */
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return ~c;
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}
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/* bits.c -- output variable-length bit strings
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@ -1223,6 +1205,9 @@ int gzip_main(int argc, char **argv)
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ALLOC(uch, window, 2L * WSIZE);
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ALLOC(ush, tab_prefix, 1L << BITS);
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/* Initialise the CRC32 table */
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crc_32_tab = bb_crc32_filltable(0);
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clear_bufs();
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part_nb = 0;
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@ -2416,7 +2401,7 @@ static void set_file_type(void)
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*/
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static ulg crc; /* crc on uncompressed file data */
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static uint32_t crc; /* crc on uncompressed file data */
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static long header_bytes; /* number of bytes in gzip header */
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static void put_long(ulg n)
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@ -84,8 +84,8 @@ typedef struct {
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/* The CRC values stored in the block header and calculated from the data */
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unsigned int crc32Table[256],headerCRC, totalCRC, writeCRC;
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uint32_t headerCRC, totalCRC, writeCRC;
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uint32_t *crc32Table;
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/* Intermediate buffer and its size (in bytes) */
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unsigned int *dbuf, dbufSize;
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@ -620,7 +620,7 @@ decode_next_byte:
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bd->writeCount=previous;
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return (previous!=RETVAL_LAST_BLOCK) ? previous : gotcount;
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}
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bd->writeCRC=0xffffffffUL;
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bd->writeCRC=~0;
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pos=bd->writePos;
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current=bd->writeCurrent;
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goto decode_next_byte;
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@ -634,7 +634,7 @@ static int start_bunzip(bunzip_data **bdp, int in_fd, unsigned char *inbuf,
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int len)
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{
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bunzip_data *bd;
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unsigned int i,j,c;
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unsigned int i;
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const unsigned int BZh0=(((unsigned int)'B')<<24)+(((unsigned int)'Z')<<16)
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+(((unsigned int)'h')<<8)+(unsigned int)'0';
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@ -657,12 +657,7 @@ static int start_bunzip(bunzip_data **bdp, int in_fd, unsigned char *inbuf,
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/* Init the CRC32 table (big endian) */
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for(i=0;i<256;i++) {
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c=i<<24;
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for(j=8;j;j--)
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c=c&0x80000000 ? (c<<1)^0x04c11db7 : (c<<1);
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bd->crc32Table[i]=c;
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}
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bd->crc32Table = bb_crc32_filltable(1);
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/* Setup for I/O error handling via longjmp */
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@ -95,8 +95,8 @@ static unsigned int gunzip_outbuf_count; /* bytes in output buffer */
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enum { gunzip_wsize = 0x8000 };
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static unsigned char *gunzip_window;
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static unsigned int *gunzip_crc_table;
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unsigned int gunzip_crc;
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static uint32_t *gunzip_crc_table;
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uint32_t gunzip_crc;
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/* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
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#define BMAX 16 /* maximum bit length of any code (16 for explode) */
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@ -168,35 +168,6 @@ static unsigned int fill_bitbuffer(unsigned int bitbuffer, unsigned int *current
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return(bitbuffer);
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}
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static void make_gunzip_crc_table(void)
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{
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const unsigned int poly = 0xedb88320; /* polynomial exclusive-or pattern */
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unsigned short i; /* counter for all possible eight bit values */
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/* initial shift register value */
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gunzip_crc = 0xffffffffL;
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gunzip_crc_table = (unsigned int *) xmalloc(256 * sizeof(unsigned int));
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/* Compute and print table of CRC's, five per line */
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for (i = 0; i < 256; i++) {
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unsigned int table_entry; /* crc shift register */
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unsigned char k; /* byte being shifted into crc apparatus */
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table_entry = i;
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/* The idea to initialize the register with the byte instead of
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* zero was stolen from Haruhiko Okumura's ar002
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*/
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for (k = 8; k; k--) {
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if (table_entry & 1) {
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table_entry = (table_entry >> 1) ^ poly;
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} else {
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table_entry >>= 1;
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}
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}
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gunzip_crc_table[i] = table_entry;
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}
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}
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/*
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* Free the malloc'ed tables built by huft_build(), which makes a linked
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* list of the tables it made, with the links in a dummy first entry of
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@ -922,7 +893,8 @@ int inflate_unzip(int in, int out)
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gunzip_bb = 0;
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/* Create the crc table */
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make_gunzip_crc_table();
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gunzip_crc_table = bb_crc32_filltable(0);
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gunzip_crc = ~0;
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/* Allocate space for buffer */
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bytebuffer = xmalloc(bytebuffer_max);
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@ -955,7 +927,7 @@ int inflate_unzip(int in, int out)
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int inflate_gunzip(int in, int out)
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{
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unsigned int stored_crc = 0;
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uint32_t stored_crc = 0;
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unsigned int count;
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inflate_unzip(in, out);
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@ -972,7 +944,7 @@ int inflate_gunzip(int in, int out)
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}
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/* Validate decompression - crc */
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if (stored_crc != (gunzip_crc ^ 0xffffffffL)) {
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if (stored_crc != (~gunzip_crc)) {
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bb_error_msg("crc error");
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return -1;
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}
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@ -508,6 +508,8 @@ void md5_begin(md5_ctx_t *ctx);
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void md5_hash(const void *data, size_t length, md5_ctx_t *ctx);
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void *md5_end(void *resbuf, md5_ctx_t *ctx);
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extern uint32_t *bb_crc32_filltable (int endian);
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/* busybox.h will include dmalloc later for us, else include it here. */
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#if !defined _BB_INTERNAL_H_ && defined DMALLOC
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#include <dmalloc.h>
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@ -13,7 +13,7 @@ LIBBB-n:=
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LIBBB-y:= \
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bb_asprintf.c ask_confirmation.c change_identity.c chomp.c \
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compare_string_array.c concat_path_file.c copy_file.c copyfd.c \
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create_icmp_socket.c create_icmp6_socket.c \
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crc32.c create_icmp_socket.c create_icmp6_socket.c \
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device_open.c dump.c error_msg.c error_msg_and_die.c find_mount_point.c \
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find_pid_by_name.c find_root_device.c fgets_str.c full_read.c \
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full_write.c get_last_path_component.c get_line_from_file.c \
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40
libbb/crc32.c
Normal file
40
libbb/crc32.c
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@ -0,0 +1,40 @@
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/* vi: set sw=4 ts=4: */
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/*
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* CRC32 table fill function
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* Copyright (C) 2006 by Rob Sullivan <cogito.ergo.cogito@gmail.com>
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* (I can't really claim much credit however, as the algorithm is
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* very well-known)
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*
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* The following function creates a CRC32 table depending on whether
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* a big-endian (0x04c11db7) or little-endian (0xedb88320) CRC32 is
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* required. Admittedly, there are other CRC32 polynomials floating
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* around, but Busybox doesn't use them.
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*
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* endian = 1: big-endian
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* endian = 0: little-endian
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include "libbb.h"
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uint32_t *bb_crc32_filltable (int endian) {
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uint32_t *crc_table = xmalloc(256 * sizeof(uint32_t));
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uint32_t polynomial = endian ? 0x04c11db7 : 0xedb88320;
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uint32_t c;
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int i, j;
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for (i = 0; i < 256; i++) {
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c = endian ? (i << 24) : i;
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for (j = 8; j; j--) {
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if (endian)
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c = (c&0x80000000) ? ((c << 1) ^ polynomial) : (c << 1);
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else
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c = (c&1) ? ((c >> 1) ^ polynomial) : (c >> 1);
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}
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*crc_table++ = c;
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}
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return crc_table - 256;
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}
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