filetype.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

		lcnt++;
			

			/* LEVEL */
		if(*p == '>') {
			ep->e_level = 1;
			p++;
		}
			/* OFFSET */
		p2 = strchr(p, '\t');
		if(p2 == NULL) {
			if(cflg)
				fprintf(stderr, "file: magic format error, no tab after %son line %d\n", p, lcnt);
			continue;
		}
		*p2++ = NULL;
		ep->e_off = atolo(p);
		while(*p2 == '\t')
			p2++;
			/* TYPE */
		p = p2;
		p2 = strchr(p, '\t');
		if(p2 == NULL) {
			if(cflg)
				fprintf(stderr, "file: magic format error, no tab after %son line %d\n", p, lcnt);
			continue;
		}
		*p2++ = NULL;
		if(*p == 's') {
			if(*(p+1) == 'h')
				ep->e_type = SHORT;
			else
				ep->e_type = STR;
		} else if (*p == 'l')
			ep->e_type = LONG;
		while(*p2 == '\t')
			*p2++;
			/* OP-VALUE */
		p = p2;
		p2 = strchr(p, '\t');
		if(p2 == NULL) {
			if(cflg)
				fprintf(stderr, "file: magic format error, no tab after %son line %d\n", p, lcnt);
			continue;
		}
		*p2++ = NULL;
		if(ep->e_type != STR) {
			opc = *p++;
			switch(opc) {
			case '=':
				ep->e_opcode = EQ;
				break;

			case '>':
				ep->e_opcode = GT;
				break;

			case '<':
				ep->e_opcode = LT;
				break;

			case 'x':
				ep->e_opcode = ANY;
				break;

			default:
				p--;
			}
		}
		if(ep->e_opcode != ANY) {
			if(ep->e_type != STR)
				ep->e_value.num = atolo(p);
			else {
				ep->e_value.str = (char *)malloc(strlen(p) + 1);
				p3 = ep->e_value.str;
				while (*p != '\0') 
				    if (*p == '\\')
					switch (*++p) {
					case 'n':
						*p3++ = '\n';
						p++;
						break;
					case 't':
						*p3++ = '\t';
						p++;
						break;
					case 'b':
						*p3++ = '\b';
						p++;
						break;
					case 'r':
						*p3++ = '\r';
						p++;
						break;
					case 'f':
						*p3++ = '\f';
						p++;
						break;
					case '0':
					case '1':
					case '2':
					case '3':
					case '4':
					case '5':
					case '6':
					case '7':
					case '8':
					case '9':
						{
						int value = 0,
						    base = 10;

						while (*p >= '0' && *p <= '9') {
							if (*p == '0' && value == 0) base = 8;
							value = value*base + (*p++ - '0');
							}
						*p3++ = (unsigned char)value;
						break;
						}
					default:
						*p3++ = *p++;
				}
			   else
				*p3++ = *p++;
			*p3 = '\0';
			p3 = (char *)fre_comp(ep->e_value.str);
			if (p3 == 0) fprintf(stderr, "file: bad reg exp in magic file: %s\n", ep->e_value.str);
			else {
				free(ep->e_value.str);
				ep->e_value.str = p3;
			}
			}
		}
		while(*p2 == '\t')
			*p2++;
			/* MAJOR/MINOR TYPE NUMBERS */
		if (sscanf(p2, "%d,%d", &majnum, &minnum) < 2)
			fprintf(stderr, "file: invalid major,minor numbers in magic file.\n");
		ep->e_retcode = MASH(majnum, minnum);
		p2 = strchr(p2, '\t');
		while(*p2 == '\t')
			*p2++;

			/* STRING */

		ep->e_str = (char *)malloc(strlen(p2) + 1);
		p = ep->e_str;
		while(*p2 != '\n') {
			if(*p2 == '%')
				ep->e_opcode |= SUB;
			*p++ = *p2++;
		}
		*p = NULL;
		ep++;
		if(ep >= mend) {
			fprintf(stderr, "file: magic table overflow.\n");
			exit(2);
		}
	}
	ep->e_off = -2L*(long)maxexecfn;
}

printmtab()
{
reg Entry *ep;

	printf("level   offset  type    opcode  major,minor	value   string\n");
	for(ep = mtab; ep->e_off > -2L*(long)maxexecfn; ep++) {
		printf("%d\t%d\t%d\t%d\t%d,%d\t",
			ep->e_level, ep->e_off, ep->e_type, ep->e_opcode, 
			(short)(ep->e_retcode>>16),
			(short)(ep->e_retcode & 0177777));
		if (ep->e_type == STR) {
			printstr(ep->e_value.str, 50);
			printf("\t");
			}
		else
			printf("%#lo\t", ep->e_value.num);
		printf("%s", ep->e_str);
		if (ep->e_opcode & SUB)
			printf("\tsubst");
		printf("\n");
	}
}

printstr(p, n)
unsigned char *p;
int n;
{

	register unsigned char *sp;
	register int c;

	for (sp = p, c = 0; *sp != '\0' && c++ < n; sp++)
		if (isprint(*sp)) printf("%c", *sp);
		else if (*sp == '\n') printf("\\n");
		else if (*sp == '\r') printf("\\r");
		else if (*sp == '\t') printf("\\t");
		else if (*sp == '\b') printf("\\b");
		else if (*sp == '\b') printf("\\f");
		else printf("\\%#o", *sp);
}

long
atolo(s)
reg	char	*s;
{
	reg	char	c;
	reg	char	*fmt = "%ld";
	auto	long	j = 0L;

	if(*s == '0') {
		s++;
		if(*s == 'x') {
			s++;
			fmt = "%lx";
		} else
			fmt = "%lo";
	}
	sscanf(s, fmt, &j);
	return(j);
}

int ci;

cprog()
{
	int j, nl;
	char ch;

	ci = 0;

	if (lookup(cstart) == 1)
		return(1);
	if(ccom() == 0) return(0);

	while(buf[ci] == '#'){
		j = ci;
		while(buf[ci++] != '\n'){
			if(ci - j > 255)
				return(0);
			if(ci >= in) return(0);
		}
		if(ccom() == 0) return(0);
	}
check:
	if(lookup(c) == 1){
		if (buf[0] == '%' && buf[1] == '!') return(0);	/* actually postscript */
		while((ch = buf[ci++]) != ';' && ch != '{')if(ci >= in) return(0);
		return(1);
	}
	nl = 0;
	while(buf[ci] != '('){
		if(buf[ci] <= 0)
			return(0);
		if(buf[ci] == ';'){
			ci++; 
			goto check; 
		}
		if(buf[ci++] == '\n')
			if(nl++ > 6) return(0);
		if(ci >= in) return(0);
	}
	while(buf[ci] != ')'){
		if(buf[ci++] == '\n')
			if(nl++ > 6) return(0);
		if(ci >= in) return(0);
	}
	while(buf[ci] != '{'){
		if(buf[ci++] == '\n')
			if(nl++ > 6) return(0);
		if(ci >= in) return(0);
	}
	if (buf[0] == '%' && buf[1] == '!') return(0);	/* actually postscript */
	return(1);
}

ccom(){
	char cc;
	while((cc = buf[ci]) == ' ' || cc == '\t' || cc == '\n')if(ci++ >= in)return(0);
	if(buf[ci] == '/' && buf[ci+1] == '*'){
		ci += 2;
		while(buf[ci] != '*' || buf[ci+1] != '/'){
			if(buf[ci] == '\\')ci += 2;
			else ci++;
			if(ci >= in)return(0);
		}
		if((ci += 2) >= in)return(0);
	}
	if(buf[ci] == '\n')if(ccom() == 0)return(0);
	return(1);
}

int
fortprog()
{
	int i = 0;

	while(buf[i] == 'c' || buf[i] == '#'){
		while(buf[i++] != '\n')if(i >= in) return(0);
	}
	if(lookup(fort) == 1)
		return(1);
	return(0);
}

ascom(){
	while(buf[i] == '/'){
		i++;
		while(buf[i++] != '\n')if(i >= in)return(0);
		while(buf[i] == '\n')if(i++ >= in)return(0);
	}
	return(1);
}

sccs() {
	reg int i;

	if(buf[0] == 1 && buf[1] == 'h')
		for(i=2; i<=6; i++)
			if(isdigit(buf[i])) continue;
			else return(0);
	else
		return(0);
	return(1);
}

troffint(bp, n)
char *bp;
int n;
{
	int k;

	i = 0;
	for (k = 0; k < 6; k++) {
		if (lookup(troff) == 0)
			return(0);
		if (lookup(troff) == 0)
			return(0);
		while (i < n && buf[i] != '\n')
			i++;
		if (i++ >= n)
			return(0);
	}
	return(1);
}
lookup(tab)
char *tab[];
{
	char r;
	int k,j,l;
	while(buf[i] == ' ' || buf[i] == '\t' || buf[i] == '\n')i++;
	for(j=0; tab[j] != 0; j++){
		l=0;
		for(k=i; ((r=tab[j][l++]) == buf[k] && r != '\0');k++);
		if(r == '\0')
			if(buf[k] == ' ' || buf[k] == '\n' || buf[k] == '\t'
			    || buf[k] == '{' || buf[k] == '/' || buf[k] == '>'){
				i=k;
				return(1);
			}
	}
	return(0);
}

english (bp, n)
char *bp;
{
# define NASC 128
	int ct[NASC], j, vow, freq, rare;
	int badpun = 0, punct = 0;
	if (n<50) return(0); /* no point in statistics on squibs */
	for(j=0; j<NASC; j++)
		ct[j]=0;
	for(j=0; j<n; j++)
	{
		if (bp[j]<NASC)
			ct[bp[j]|040]++;
		switch (bp[j])
		{
		case '.': 
		case ',': 
		case ')': 
		case '%':
		case ';': 
		case ':': 
		case '?':
			punct++;
			if ( j < n-1 &&
			    bp[j+1] != ' ' &&
			    bp[j+1] != '\n')
				badpun++;
		}
	}
	if (badpun*5 > punct)
		return(0);
	vow = ct['a'] + ct['e'] + ct['i'] + ct['o'] + ct['u'];
	freq = ct['e'] + ct['t'] + ct['a'] + ct['i'] + ct['o'] + ct['n'];
	rare = ct['v'] + ct['j'] + ct['k'] + ct['q'] + ct['x'] + ct['z'];
	if (2*ct[';'] > ct['e']) return(0);
	if ( (ct['>']+ct['<']+ct['/'])>ct['e']) return(0); /* shell file test */
	return (vow*5 >= n-ct[' '] && freq >= 10*rare);
}

shell(bp, n, tab)
	char *bp;
	int n;
	char *tab[];
{

	i = 0;
	do {
		if (buf[i] == '#' || buf[i] == ':')
			while (i < n && buf[i] != '\n')
				i++;
		if (++i >= n)
			break;
		if (lookup(tab) == 1)
			return (1);
	} while (i < n);
	return (0);
}