/*
  "decode.c" ish for Human68
  ken.Miyazaki & o.imaizumi
  1987/12/05 OS9ext support
  1988/02/01 same as OSK version.
  1988/02/06 for Human68K. (Gigo)
  1988/05/10 for UNIX (kondo)
  1990/07/13 non-kana (keizo)
*/

#include <ctype.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifdef SysV
#include <time.h>
#define index   strchr
#else
#ifdef __TURBOC__
#include <time.h>
#include <io.h>
#define index   strchr
#else
#include <sys/time.h>
#endif
#endif
#include <fcntl.h>
#include "ish.h"

#define isleapyear(y)   (((y)%4 == 0 && (y)%100 != 0 || (y)%400 == 0))

void hedprn();

struct tm tm;
time_t timep[2], seconds();

int  type,dline;
unsigned char decbuf[LBUFLEN][LBUFLEN];

extern unsigned char *index();
extern int errno;

decode()
{
    int l, skip = 0,fc = 0;

    while((l = readln(ipath, buff, LBUFLEN)) > 0) {
	if (l > 60) {
	    switch(*buff) {
	    case '!':
		l = dec_jis7(buff, l);
		break;
	    case '#':
		l = dec_jis8(buff, l);
		break;
	    case '@':
		l = dec_sjis(buff, l);
		break;
	    default:
		l = 0;
		break;
	    }
	    if (l > 60) {
		if (chkcrc(obuf, l)) {
		    if (obuf[0] == '\0') {
			if (skip == 0) {
			    fc++;
			    hedprn(obuf);
			    skip = decish();
			}
			continue;
		    }
		    else {
			fprintf(stderr, "Can't Found Header\n");
			skip = 0;
			continue;
		    }
		}
	    }
	}
	skip = 0;
    } /* EOF */
    return(fc);
}

typedef struct {
    unsigned char sinc;
    unsigned char itype;
    unsigned char fsize[4];
    unsigned char line[2];
    unsigned short block;
    unsigned char byte;
    unsigned char ibyte;
    unsigned char iname[11];
    unsigned char janle;
    unsigned char os;
    unsigned char exttype;
    unsigned char tstamp;
    unsigned char time[4];
    unsigned char atr;		/* 32:    OS-9Ext only */
    unsigned char ename[29];	/* 33-61: OS-9Ext only */
} ish_head;

void hedprn(head)
ish_head *head;
{
    int i;
    unsigned char *p, *s;

    p = head->fsize;
    lsize = (long)p[0]+((long)p[1]<<8)+((long)p[2]<<16)+((long)p[3]<<24);
    p = head->line;
    jis = (long)p[0]+((long)p[1]<<8);
    type = head->ibyte;
    os = head->os;
    for(p = head->iname, s = name, i = 0; i < 8; i++) {
	*s++ = *p++;
	if (*p == ' ')
	    break;
    }
    for(p = head->iname+8, i = 0; i < 3; i++) {
	if (*p == ' ')
	    break;
	if (i == 0)
	    *s++ = '.';
	*s++ = *p++;
    }
    *s = '\0';
    fprintf(stderr, "<<< %s from ",name);
    switch(os) {
    case MS_DOS:
	fprintf(stderr, "MS-DOS");
	break;
    case CP_M:
	fprintf(stderr, "CP/M or MSX-DOS");
	break;
    case OS_9:
	fprintf(stderr, "OS-9");
	break;
    case OS_9EXT:
	fprintf(stderr, "OS-9Ext");
	break;
    case UNIX:
	fprintf(stderr, "UNIX");
	break;
    case OTHER:
	fprintf(stderr, "OTHER");
	break;
    case ALL_OS :
	fprintf(stderr, "ALL-OS");
	break;
    default:
	printf("?????");
    }
    fprintf(stderr, " ( use ");
    switch(type) {
    case 13:
	fprintf(stderr, "jis7");
	break;
    case 8:
	fprintf(stderr, "jis8");
	break;
    case 14:
	fprintf(stderr, "shift_jis non-kana");
	break;
    case 15:
	fprintf(stderr, "shift_jis");
	break;
    }
    fprintf(stderr, " ) ");
    if (head->tstamp != 0) {
	p = head->time;
	tm.tm_year = (p[3]>>1)+80;
	tm.tm_mon = (p[3]&0x01)<<3;
	tm.tm_mon += (p[2]>>5) - 1;
	tm.tm_mday = p[2]&0x1f;
	tm.tm_hour = p[1]>>3;
	tm.tm_min = (p[1]&0x07)<<3;
	tm.tm_min += p[0]>>5;
	tm.tm_sec = (p[0]&0x1f)<<1;
	fprintf(stderr,"%02d/%02d/%02d %02d:%02d:%02d ",
	    tm.tm_year,tm.tm_mon+1,tm.tm_mday,tm.tm_hour,tm.tm_min,tm.tm_sec);
#ifdef __TURBOC__
	memcpy( &timep[0], head->time, 4);
	timep[1] = timep[0];
#else
	timep[0] = timep[1] = seconds(&tm);
#endif
    }
    fprintf(stderr, "%ld byte >>>\n", lsize);

    switch(type) {		/* 90-7-13 */
    case 13:
		edmode = JIS7;
		break;
    case 8:
		edmode = JIS8;
		break;
    case 14:
		edmode = NJIS;
		break;
    case 15:
		edmode = SJIS;
		break;
    }
}

decish()
{
    int fp, i, j;
    unsigned char *p;
    unsigned short crc, ncrc;

    if (access(name,0) == 0) {
	switch(mode) {
	case RESASK:
	    fprintf(stderr, "'%s' already exist. replace ? (y/[n]/q):", name);
	    fflush(stderr);
	    if (read(0, buff, LBUFLEN) <= 0)
			buff[0] = 'n';
	    buff[0] = isalpha(buff[0]) ? toupper(buff[0]) : buff[0];
	    if (buff[0] == 'Q')
		exit(0);
	    if (buff[0] == 'Y') {
		if(unlink(name) != ERR)
		    break;
		fprintf(stderr, "'%s' - can't replace.\n", name);
	    }
	    return -1;
	case RESNEW:
	    fprintf(stderr, "'%s' - file already exist. Skip it.\n", name);
	    return -1;
	case RESALL:
	    i = 0;
	    fprintf(stderr, "file name change '%s'", name);
	    strcpy(buff, name);
	    if(p = index(name, '.'))
		*p = NULL;
	    do {
		sprintf(buff, "%s.%03d", name, i++);
	    } while(access(buff,0) == 0);
	    fprintf(stderr, " to '%s'\n", buff);
	    strcpy(name, buff);
	    break;
	}
    }
    umask(i = umask(022));
#ifdef __TURBOC__
    if ((fp = _creat(name, 0x20)) == ERR) {
#else
    if ((fp = creat(name, 0666&~i)) == ERR) {
#endif
	fprintf(stderr, "ish: Can't open:%s\n", name);
	exit(errno);
    }
    crc = 0xffff;
    lsize += 2;
    dline = lsize/(jis-3) + 1;
    fprintf(stderr, "%s : ", name);
    while (lsize > 0) {
	if (decblk() != 0)
	    fprintf(stderr, " Error!!\007\n");
	fflush(stderr);
	for (i = 1; i < jis-2; ++i) {
	    if (lsize < (jis-3))
		j = lsize;
	    else
		j = jis-3;
	    lsize -= j;
	    if (lsize >= 2) {
		crc = calcrc(&decbuf[i][1], j, crc);
		write(fp, &decbuf[i][1], j);
	    }
	    else if (lsize == 1) {
		crc = calcrc(&decbuf[i][1], j-1, crc);
		write(fp, &decbuf[i][1], j-1);
		ncrc = decbuf[i][j] << 8;
	    }
	    else {
		if (j >= 2) {
		    if (j > 2) {
			crc = calcrc(&decbuf[i][1], j-2, crc);
			write(fp, &decbuf[i][1], j-2);
		    }
		    ncrc = decbuf[i][j-1] << 8 | unschr(decbuf[i][j]);
		}
		else {
		    ncrc |= unschr(decbuf[i][1]);
		}
		break;
	    }
	}
    }
    if ((crc=~crc) != ncrc)
	fprintf(stderr, " CRC Error : %04X(%04X)\007\n", crc, ncrc);
    else
	fprintf(stderr, " Finished.\n");
#ifdef __TURBOC__
	setftime(fp, timep);
	close(fp);
#else
    utime(name, timep);
#endif
    return 0;
}

decblk()
{
    static int seq = 0; /* for out of sequence check */
    int i, j, k, n, err, bad[2];

    /* reset decode buffer */

    for (i = 0; i <= jis; decbuf[i++][0] = '\0');
    if (seq)    /* put back ln */
	for (i=0; i < jis-2; i++)
	    decbuf[seq][i] = obuf[i];
    seq = 0;
    while ((i = readln(ipath, buff, LBUFLEN)) > 0) {
	if (i < 60)
	    continue;
	if ((k = dec_j(buff, i)) < jis)
	    continue;
	if (chkcrc(obuf,k) == 0)
	    continue;
	if ((j = obuf[0]) > jis)
	    continue;
	if (j < seq) {
	    seq = j;
	    break;
	}
	else {
	    seq = j;
	    for (n=0; n < jis-2; ++n)
		decbuf[j][n] = obuf[n];
	    if (j == jis){
		seq = 0;
		break;
	    }
	}
    }
    k = (dline < jis-3) ? dline : jis-3;
    dline -= k;
    if (i <= 0 && dline > 2) {
	fprintf(stderr, " Warning - unexpected end of file");
	return -1;
    }
    for (i=1, err=0; i < jis-2; i++) {
	if (decbuf[i][0] == '\0') {
	    decbuf[i][0] = i;
	    for(j = 1; j < jis-2; decbuf[i][j++] = 0);
	    if (i <= k) {
		if (err < 2)
		    bad[err] = i;
		err++;
	    }
	}
    }
    if (err == 0) {
	fprintf(stderr, "o");
	return(0);
    }
    if (err <= 2)
	if (ecc(err, bad[0], bad[1]) == 0){
	    fprintf(stderr, "%d",err);
	    return(0);
	}
	else
	    err = 3;
    fprintf(stderr, "%d <- too many", err);
    return ERR;
}

dec_j(argv, len)
unsigned char *argv;
int len;
{
    switch(type) {
    case 13:
	return dec_jis7(argv, len);
    case 8 :
	return dec_jis8(argv, len);
    case 14:
	return dec_njis(argv, len);
    case 15:
	return dec_sjis(argv, len);
    default:
	return 0;
    }
}

/*
  "ecc.c" ish for OS9/OSK
  Error collection routine
  87/12/17,88/01/30 By Gigo
  (original idea by M.ishizuka)
*/

ecc(err, e1, e2)
int err, e1, e2;
{
    register unsigned sum;
    register int i, j, k, x;

    if (err == 1) {     /* 1 line error correct (easy!) */
	if (decbuf[jis-2][0] != '\0') {
	    for (j = 1; j < jis-2; j++) {
		for(i=1, sum=0; i < jis-1; sum -= decbuf[i++][j]);
		decbuf[e1][j] = sum;
	    }
	    return 0;
	}
	e2 = jis-2;     /* oh! checksum(V) error increase */
	decbuf[e2][0] = e2;
	for(j = 1; j < jis-2; decbuf[e2][j++] = 0);
    }

    /* correct 2 line error */

    if (decbuf[jis][0] == '\0')      /* no checksum(T) line, give up */
	return 3;

    /* calc hidden byte */

    switch(edmode) {
    case JIS7:
	sum = 0x9d;
	break;
    case JIS8:
	case NJIS:
	sum = 0x1a;
	break;
    case SJIS:
	sum = 0x04;
	break;
    }

    for(j = 1; j < jis-2; j++)
	sum -= decbuf[jis][j];
    decbuf[jis][0] = sum;

    /* clear & set */

    for(j = 0; j < jis; j++)
	decbuf[jis-1][j] = 0;

    x = 0;

    for(k = 0; k < jis-3 ;k++) {     /* search scanning pass */
	if (x <= e1)               /* use '?' oprater, clash !! Oops! */
	    j = jis-1-e1+x;
	else
	    j = x-e1+1;

	/* travase */

	for(i = 1, sum = 0;i <= jis ;j++, i++) {
	    j=j % (jis-2);
	    sum -= decbuf[i][j];
	}
	decbuf[e2][x=((x+e2-e1)%(jis-2))] = sum;

	/* vartical checksum */

	for(i=1, sum=0; i < jis-1; i++)
	    sum -= decbuf[i][x];
	decbuf[e1][x] = sum;
    }
    return 0;
}

int readln(ipath, buff, maxlen)
FILE *ipath;
int maxlen;
char *buff;
{
    int c, i;

    i = 0;

    while((c = fgetc(ipath)) != EOF && maxlen > i) {
	if((c > 0x1f) && (c != 0x7f)) {
	    buff[i++] = c;
	}
	if ((c == '\n') && i)
	    break;
    }
    buff[i] = NULL;
    return i;
}

#ifndef __TURBOC__
int days(t)
struct tm *t;
{
    int y = t->tm_year+1900-1, m = t->tm_mon, d = t->tm_mday-1;
    static unsigned short month[] = {
	0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
    };

    d += 365*y - 718685;    /* (1970-1)*365 */
    d += y/4 - 492;     /* (1970-1)/4 */
    d -= y/100 - 19;    /* (1970-1)/100 */
    d += (y++)/400 - 4; /* (1970-1)/400 */
    d += (long)month[m];
    if (isleapyear(y) && m > 1)
	d++;
    return d;
}

time_t seconds(t)
struct tm *t;
{
    long s;
#ifdef SysV
    extern int timezone;
#else
    struct timeval tv;
    struct timezone tz;
    int timezone;

    gettimeofday(&tv, &tz);
    timezone = tz.tz_minuteswest * 60;
#endif
    s = (long)days(t)*86400+t->tm_hour*3600+t->tm_min*60+t->tm_sec;
    s += timezone;

#ifdef DST
    t = localtime(&s);
    if (t->t_isdst)
	s -= 3600;
#endif
    return s;
}

#endif