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/*$Source: /usr/home/dhesi/zoo/RCS/io.c,v $*/
/*$Id: io.c,v 1.14 91/07/09 01:39:54 dhesi Exp $*/
/***********************************************************
io.c -- input/output
Adapted from "ar" archiver written by Haruhiko Okumura.
***********************************************************/
#ifdef ANSI_HDRS
# include <stdlib.h>
# include <string.h>
#endif
#include "options.h"
#include "zoo.h"
#include "ar.h"
#include "lzh.h"
#include "zooio.h" /* for NULLFILE */
#include "portable.h"
extern void prterror();
#include "errors.i"
#define JUST_LZH /* for stand-alone compression */
#if 0
# define CRCPOLY 0xA001 /* ANSI CRC-16 */ /* CCITT: 0x8408 */
# define UPDATE_CRC(c) \
crc = crctable[(crc ^ (c)) & 0xFF] ^ (crc >> CHAR_BIT)
static ushort crctable[UCHAR_MAX + 1];
t_uint16 crc;
#endif
extern FILE *arcfile, *lzh_outfile;
t_uint16 bitbuf;
int unpackable;
ulong compsize, origsize;
static uint subbitbuf;
static int bitcount;
#if 0
void make_crctable()
{
uint i, j, r;
for (i = 0; i <= UCHAR_MAX; i++) {
r = i;
for (j = 0; j < CHAR_BIT; j++)
if (r & 1) r = (r >> 1) ^ CRCPOLY;
else r >>= 1;
crctable[i] = r;
}
}
#endif
void fillbuf(n) /* Shift bitbuf n bits left, read n bits */
int n;
{
bitbuf <<= n;
while (n > bitcount) {
bitbuf |= subbitbuf << (n -= bitcount);
#ifdef JUST_LZH
if (feof(arcfile))
subbitbuf = 0;
else
subbitbuf = (uchar) zgetc(arcfile);
#else
if (compsize != 0) {
compsize--; subbitbuf = (uchar) zgetc(arcfile);
} else subbitbuf = 0;
#endif /* JUST_LZH */
bitcount = CHAR_BIT;
}
bitbuf |= subbitbuf >> (bitcount -= n);
}
uint getbits(n)
int n;
{
uint x;
x = bitbuf >> (BITBUFSIZ - n); fillbuf(n);
return x;
}
void putbits(n, x) /* Write rightmost n bits of x */
int n;
uint x;
{
if (n < bitcount) {
subbitbuf |= x << (bitcount -= n);
} else {
#ifdef JUST_LZH
(void) putc((int) (subbitbuf | (x >> (n -= bitcount))), lzh_outfile);
compsize++;
#else
if (compsize < origsize) {
(void) zputc((int) (subbitbuf | (x >> (n -= bitcount))), lzh_outfile);
compsize++;
} else unpackable = 1;
#endif /* JUST_LZH */
if (n < CHAR_BIT) {
subbitbuf = x << (bitcount = CHAR_BIT - n);
} else {
#ifdef JUST_LZH
(void) putc((int) (x >> (n - CHAR_BIT)), lzh_outfile);
compsize++;
#else
if (compsize < origsize) {
(void) zputc((int) (x >> (n - CHAR_BIT)), lzh_outfile);
compsize++;
} else unpackable = 1;
#endif /* JUST_LZH */
subbitbuf = x << (bitcount = 2 * CHAR_BIT - n);
}
}
}
extern void addbfcrc();
int fread_crc(p, n, f)
uchar *p;
int n;
FILE *f;
{
int i;
i = n = fread((char *) p, 1, n, f); origsize += n;
addbfcrc(p, i);
return n;
}
void fwrite_crc(p, n, f)
uchar *p;
int n;
FILE *f;
{
if (f != NULLFILE) {
if (fwrite((char *) p, 1, n, f) < n)
prterror('f', disk_full);
}
addbfcrc(p, n);
}
void init_getbits()
{
bitbuf = 0; subbitbuf = 0; bitcount = 0;
fillbuf(BITBUFSIZ);
}
void init_putbits()
{
bitcount = CHAR_BIT; subbitbuf = 0;
}
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