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OS/2 Shareware BBS: 9 Archive
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09-Archive.zip
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lha100bt.zip
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lha-1.00
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src
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crcio.c
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C/C++ Source or Header
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1992-04-04
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6KB
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341 lines
/***********************************************************
crcio.c -- input/output
***********************************************************/
#ifdef __STDC__
#include <stdlib.h>
#include <stdarg.h>
#endif
#include <errno.h>
#include "slidehuf.h"
#include "intrface.h"
extern int text_mode;
extern int prev_char;
extern int verify_mode;
#ifdef EUC
extern int euc_mode;
extern int generic_format;
#endif
long reading_size;
#define CRCPOLY 0xA001 /* CRC-16 */
#define UPDATE_CRC(c) \
crc = crctable[(crc ^ (c)) & 0xFF] ^ (crc >> CHAR_BIT)
FILE *infile, *outfile;
unsigned short crc, bitbuf;
static unsigned short crctable[UCHAR_MAX + 1];
static unsigned char subbitbuf, bitcount;
#ifdef EUC
static int putc_euc_cache;
#endif
static int getc_euc_cache;
void make_crctable(void)
{
unsigned int 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;
}
}
#ifdef NEED_INCREMENTAL_INDICATOR
extern int quiet;
extern int indicator_count;
extern int indicator_threshold;
static void
put_indicator( count )
long int count;
{
if (!quiet && indicator_threshold)
{
while ( count > indicator_count) {
putchar ('o');
fflush (stdout);
indicator_count += indicator_threshold;
}
}
}
#endif
unsigned short calccrc( p , n )
unsigned char *p;
unsigned int n;
{
reading_size += n;
#ifdef NEED_INCREMENTAL_INDICATOR
put_indicator( reading_size );
#endif
while (n-- > 0) UPDATE_CRC(*p++);
return crc;
}
void fillbuf(n) /* Shift bitbuf n bits left, read n bits */
unsigned char n;
{
while (n > bitcount) {
n -= bitcount;
bitbuf = (bitbuf << bitcount) + (subbitbuf >> (CHAR_BIT - bitcount));
if (compsize != 0) {
compsize--; subbitbuf = (unsigned char) getc(infile);
} else subbitbuf = 0;
bitcount = CHAR_BIT;
}
bitcount -= n;
bitbuf = (bitbuf << n) + (subbitbuf >> (CHAR_BIT - n));
subbitbuf <<= n;
}
unsigned short getbits(n)
unsigned char n;
{
unsigned short x;
x = bitbuf >> (2 * CHAR_BIT - n); fillbuf(n);
return x;
}
void putcode( n , x ) /* Write rightmost n bits of x */
unsigned char n;
unsigned short x;
{
while (n >= bitcount) {
n -= bitcount;
subbitbuf += x >> (USHRT_BIT - bitcount);
x <<= bitcount;
if (compsize < origsize) {
if (fwrite(&subbitbuf, 1, 1, outfile) == 0)
/* fileerror(WTERR, outfile); */
exit( errno );
compsize++;
} else unpackable = 1;
subbitbuf = 0; bitcount = CHAR_BIT;
}
subbitbuf += x >> (USHRT_BIT - bitcount);
bitcount -= n;
}
void putbits( n , x ) /* Write rightmost n bits of x */
unsigned char n;
unsigned short x;
{
x <<= USHRT_BIT - n;
while (n >= bitcount) {
n -= bitcount;
subbitbuf += x >> (USHRT_BIT - bitcount);
x <<= bitcount;
if (compsize < origsize) {
if (fwrite(&subbitbuf, 1, 1, outfile) == 0)
/* fileerror(WTERR, outfile); */
exit( errno );
compsize++;
} else unpackable = 1;
subbitbuf = 0; bitcount = CHAR_BIT;
}
subbitbuf += x >> (USHRT_BIT - bitcount);
bitcount -= n;
}
int fread_crc( p, n, fp )
unsigned char *p;
int n;
FILE *fp;
{
if ( text_mode )
n = fread_txt(p, n, fp);
else
n = fread(p, 1, n, fp);
calccrc(p, n);
return n;
}
void fwrite_crc( p, n, fp )
unsigned char *p;
int n;
FILE *fp;
{
calccrc(p,n);
if ( verify_mode ) return;
if ( fp )
{
if ( text_mode )
{
if ( fwrite_txt(p , n , fp) )
fatal_error("File write error\n");
}
else
{
if (fwrite(p, 1, n, fp) < n)
fatal_error("File write error\n");
}
}
}
void init_code_cache(void) /* called from copyfile() in util.c */
{
#ifdef EUC
putc_euc_cache = EOF;
#endif
getc_euc_cache = EOF;
}
void init_getbits(void)
{
bitbuf = 0; subbitbuf = 0; bitcount = 0;
fillbuf(2 * CHAR_BIT);
#ifdef EUC
putc_euc_cache = EOF;
#endif
}
void init_putbits(void)
{
bitcount = CHAR_BIT; subbitbuf = 0;
getc_euc_cache = EOF;
}
#ifdef EUC
void
putc_euc(c, fd)
int c;
FILE *fd;
{
int d;
if (putc_euc_cache == EOF)
{
if (!euc_mode || c < 0x81 || c > 0xFC)
{
putc(c, fd);
return;
}
if (c >= 0xA0 && c < 0xE0)
{
putc(0x8E, fd); /* single shift */
putc(c, fd);
return;
}
putc_euc_cache = c; /* save first byte */
return;
}
d = putc_euc_cache;
putc_euc_cache = EOF;
if (d >= 0xA0)
d -= 0xE0 - 0xA0;
if (c > 0x9E)
{
c = c - 0x9F + 0x21;
d = (d - 0x81) * 2 + 0x22;
}
else
{
if (c > 0x7E)
c --;
c -= 0x1F;
d = (d - 0x81) * 2 + 0x21;
}
putc(0x80 | d, fd);
putc(0x80 | c, fd);
}
#endif
int
fwrite_txt( p , n , fp )
unsigned char *p;
int n;
FILE *fp;
{
while ( --n>=0 )
{
if ( *p!='\015' && *p!='\032' )
{
#ifdef EUC
putc_euc( *p , fp );
#else
putc( *p , fp );
#endif
}
prev_char = *p++;
}
return ( ferror( fp ) );
}
int
fread_txt( p , n , fp )
unsigned char *p;
int n;
FILE *fp;
{
int c;
int cnt = 0;
while (cnt < n)
{
if (getc_euc_cache != EOF)
{
c = getc_euc_cache;
getc_euc_cache = EOF;
}
else
{
if ((c = fgetc(fp)) == EOF)
break;
if (c == '\n') {
getc_euc_cache = c;
c = '\r';
}
#ifdef EUC
else if (euc_mode && (c == 0x8E || 0xA0 < c && c < 0xFF))
{
int d = fgetc(fp);
if (d == EOF)
{
*p++ = c;
cnt ++;
break;
}
if (c == 0x8E) /* single shift (KANA) */
{
if ((0x20 < d && d < 0x7F) || (0xA0 < d && d < 0xFF))
c = d | 0x80;
else
getc_euc_cache = d;
}
else
{
if (0xA0 < d && d < 0xFF) /* if GR */
{
c &= 0x7F; /* convert to MS-kanji */
d &= 0x7F;
if (!(c & 1))
{
c --;
d += 0x7F - 0x21;
}
if ((d += 0x40 - 0x21) > 0x7E)
d ++;
if ((c = (c >> 1) + 0x71) >= 0xA0)
c += 0xE0 - 0xA0;
}
getc_euc_cache = d;
}
}
#endif
}
*p++ = c;
cnt ++;
}
return cnt;
}