diff options
Diffstat (limited to 'gzip.c')
| -rw-r--r-- | gzip.c | 129 |
1 files changed, 122 insertions, 7 deletions
@@ -42,6 +42,7 @@ #include <stdio.h> #include <string.h> #include <unistd.h> +#include <errno.h> #include "busybox.h" #define BB_DECLARE_EXTERN #define bb_need_memory_exhausted @@ -72,7 +73,7 @@ typedef unsigned long ulg; /* methods 4 to 7 reserved */ #define DEFLATED 8 #define MAX_METHODS 9 -extern int method; /* compression method */ +static int method; /* compression method */ /* To save memory for 16 bit systems, some arrays are overlaid between * the various modules: @@ -143,7 +144,7 @@ EXTERN(ush, tab_prefix1); /* prefix for odd codes */ #endif extern unsigned insize; /* valid bytes in inbuf */ -extern unsigned inptr; /* index of next byte to be processed in inbuf */ +static unsigned inptr; /* index of next byte to be processed in inbuf */ extern unsigned outcnt; /* bytes in output buffer */ extern long bytes_in; /* number of input bytes */ @@ -308,16 +309,16 @@ extern int (*read_buf) (char *buf, unsigned size); /* in util.c: */ extern int copy (int in, int out); -extern ulg updcrc (uch * s, unsigned n); -extern void clear_bufs (void); +//extern ulg updcrc (uch * s, unsigned n); +//extern void clear_bufs (void); extern int fill_inbuf (int eof_ok); extern void flush_outbuf (void); extern void flush_window (void); -extern void write_buf (int fd, void * buf, unsigned cnt); +//extern void write_buf (int fd, void * buf, unsigned cnt); extern char *strlwr (char *s); extern char *add_envopt (int *argcp, char ***argvp, char *env); -extern void read_error_msg (void); -extern void write_error_msg (void); +//extern void read_error_msg (void); +//extern void write_error_msg (void); extern void display_ratio (long num, long den, FILE * file); /* in inflate.c */ @@ -704,6 +705,120 @@ extern void _expand_args(int *argc, char ***argv); #ifndef put_char # define put_char(c) put_byte(c) #endif + +int crc_table_empty = 1; + +/* ======================================================================== + * Signal and error handler. + */ +void abort_gzip() +{ + exit(ERROR); +} + +/* =========================================================================== + * Clear input and output buffers + */ +static void clear_bufs(void) +{ + outcnt = 0; + insize = inptr = 0; + bytes_in = bytes_out = 0L; +} + +static void write_error_msg() +{ + fprintf(stderr, "\n"); + perror(""); + abort_gzip(); +} + +/* =========================================================================== + * Does the same as write(), but also handles partial pipe writes and checks + * for error return. + */ +static void write_buf(fd, buf, cnt) +int fd; +void * buf; +unsigned cnt; +{ + unsigned n; + + while ((n = write(fd, buf, cnt)) != cnt) { + if (n == (unsigned) (-1)) { + write_error_msg(); + } + cnt -= n; + buf = (void *) ((char *) buf + n); + } +} + +/* ======================================================================== + * Error handlers. + */ +static void read_error_msg() +{ + fprintf(stderr, "\n"); + if (errno != 0) { + perror(""); + } else { + fprintf(stderr, "unexpected end of file\n"); + } + abort_gzip(); +} + +/* =========================================================================== + * Run a set of bytes through the crc shift register. If s is a NULL + * pointer, then initialize the crc shift register contents instead. + * Return the current crc in either case. + */ +static ulg updcrc(s, n) +uch *s; /* pointer to bytes to pump through */ +unsigned n; /* number of bytes in s[] */ +{ + static ulg crc = (ulg) 0xffffffffL; /* shift register contents */ + register ulg c; /* temporary variable */ + static unsigned long crc_32_tab[256]; + if (crc_table_empty) { + unsigned long csr; /* crc shift register */ + unsigned long e; /* polynomial exclusive-or pattern */ + int i; /* counter for all possible eight bit values */ + int k; /* byte being shifted into crc apparatus */ + + /* terms of polynomial defining this crc (except x^32): */ + static int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26}; + + /* Make exclusive-or pattern from polynomial (0xedb88320) */ + e = 0; + for (i = 0; i < sizeof(p)/sizeof(int); i++) + e |= 1L << (31 - p[i]); + + /* Compute and print table of CRC's, five per line */ + crc_32_tab[0] = 0x00000000L; + 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; + } + } + + if (s == NULL) { + c = 0xffffffffL; + } else { + c = crc; + if (n) + do { + c = crc_32_tab[((int) c ^ (*s++)) & 0xff] ^ (c >> 8); + } while (--n); + } + crc = c; + return c ^ 0xffffffffL; /* (instead of ~c for 64-bit machines) */ +} + /* bits.c -- output variable-length bit strings * Copyright (C) 1992-1993 Jean-loup Gailly * This is free software; you can redistribute it and/or modify it under the |