/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>#include <bio.h>#include <ctype.h>#include "diff.h" struct line {	int	serial;	int	value;};extern struct line *file[2];extern int len[2];extern long *ixold, *ixnew;extern int *J; static Biobuf *input[2];static char *file1, *file2;static int firstchange; #define MAXLINELEN	4096#define MIN(x, y)	((x) < (y) ? (x): (y)) static intreadline(Biobuf *bp, char *buf){	int c;	char *p, *e; 	p = buf;	e = p + MAXLINELEN-1;	do {		c = Bgetc(bp);		if (c < 0) {			if (p == buf)				return -1;			break;		}		if (c == '\n')			break;		*p++ = c;	} while (p < e);	*p = 0;	if (c != '\n' && c >= 0) {		do c = Bgetc(bp);		while (c >= 0 && c != '\n');	}	return p - buf;} #define HALFLONG 16#define low(x)	(x&((1L<<HALFLONG)-1))#define high(x)	(x>>HALFLONG) /* * hashing has the effect of * arranging line in 7-bit bytes and then * summing 1-s complement in 16-bit hunks  */static intreadhash(Biobuf *bp, char *buf){	long sum;	unsigned shift;	char *p;	int len, space; 	sum = 1;	shift = 0;	if ((len = readline(bp, buf)) == -1)		return 0;	p = buf;	switch(bflag)	/* various types of white space handling */	{	case 0:		while (len--) {			sum += (long)*p++ << (shift &= (HALFLONG-1));			shift += 7;		}		break;	case 1:		/*		 * coalesce multiple white-space		 */		for (space = 0; len--; p++) {			if (isspace(*p)) {				space++;				continue;			}			if (space) {				shift += 7;				space = 0;			}			sum += (long)*p << (shift &= (HALFLONG-1));			shift += 7;		}		break;	default:		/*		 * strip all white-space		 */		while (len--) {			if (isspace(*p)) {				p++;				continue;			}			sum += (long)*p++ << (shift &= (HALFLONG-1));			shift += 7;		}		break;	}	sum = low(sum) + high(sum);	return ((short)low(sum) + (short)high(sum));} Biobuf *prepare(int i, char *arg){	struct line *p;	int j, h;	Biobuf *bp;	char *cp, buf[MAXLINELEN];	int nbytes;	Rune r; 	bp = Bopen(arg, OREAD);	if (!bp) {		panic(mflag ? 0: 2, "cannot open %s: %r\n", arg);		return 0;	}	if (binary)		return bp;	nbytes = Bread(bp, buf, MIN(1024, MAXLINELEN));	if (nbytes > 0) {		cp = buf;		while (cp < buf+nbytes-UTFmax) {			/*			 * heuristic for a binary file in the			 * brave new UNICODE world			 */			cp += chartorune(&r, cp);			if (r == 0 || (r > 0x7f && r <= 0xa0)) {				binary++;				return bp;			}		}		Bseek(bp, 0, 0);	}	p = MALLOC(struct line, 3);	for (j = 0; h = readhash(bp, buf); p[j].value = h)		p = REALLOC(p, struct line, (++j+3));	len[i] = j;	file[i] = p;	input[i] = bp;			/*fix*/	if (i == 0) {			/*fix*/		file1 = arg;		firstchange = 0;	}	else		file2 = arg;	return bp;} static intsquishspace(char *buf){	char *p, *q;	int space; 	for (space = 0, q = p = buf; *q; q++) {		if (isspace(*q)) {			space++;			continue;		}		if (space && bflag == 1) {			*p++ = ' ';			space = 0;		}		*p++ = *q;	}	*p = 0;	return p - buf;} /* * need to fix up for unexpected EOF's */voidcheck(Biobuf *bf, Biobuf *bt){	int f, t, flen, tlen;	char fbuf[MAXLINELEN], tbuf[MAXLINELEN]; 	ixold[0] = ixnew[0] = 0;	for (f = t = 1; f < len[0]; f++) {		flen = readline(bf, fbuf);		ixold[f] = ixold[f-1] + flen + 1;		/* ftell(bf) */		if (J[f] == 0)			continue;		do {			tlen = readline(bt, tbuf);			ixnew[t] = ixnew[t-1] + tlen + 1;	/* ftell(bt) */		} while (t++ < J[f]);		if (bflag) {			flen = squishspace(fbuf);			tlen = squishspace(tbuf);		}		if (flen != tlen || strcmp(fbuf, tbuf))			J[f] = 0;	}	while (t < len[1]) {		tlen = readline(bt, tbuf);		ixnew[t] = ixnew[t-1] + tlen + 1;	/* fseek(bt) */		t++;	}} static voidrange(int a, int b, char *separator){	Bprint(&stdout, "%d", a > b ? b: a);	if (a < b)		Bprint(&stdout, "%s%d", separator, b);} static voidfetch(long *f, int a, int b, Biobuf *bp, char *s){	char buf[MAXLINELEN];	int maxb; 	if(a <= 1)		a = 1;	if(bp == input[0])		maxb = len[0];	else		maxb = len[1];	if(b > maxb)		b = maxb;	if(a > maxb)		return;	Bseek(bp, f[a-1], 0);	while (a++ <= b) {		readline(bp, buf);		Bprint(&stdout, "%s%s\n", s, buf);	}} typedef struct Change Change;struct Change{	int a;	int b;	int c;	int d;}; Change *changes;int nchanges; voidchange(int a, int b, int c, int d){	char verb;	char buf[4];	Change *ch; 	if (a > b && c > d)		return;	anychange = 1;	if (mflag && firstchange == 0) {		if(mode) {			buf[0] = '-';			buf[1] = mode;			buf[2] = ' ';			buf[3] = '\0';		} else {			buf[0] = '\0';		}		Bprint(&stdout, "diff %s%s %s\n", buf, file1, file2);		firstchange = 1;	}	verb = a > b ? 'a': c > d ? 'd': 'c';	switch(mode) {	case 'e':		range(a, b, ",");		Bputc(&stdout, verb);		break;	case 0:		range(a, b, ",");		Bputc(&stdout, verb);		range(c, d, ",");		break;	case 'n':		Bprint(&stdout, "%s:", file1);		range(a, b, ",");		Bprint(&stdout, " %c ", verb);		Bprint(&stdout, "%s:", file2);		range(c, d, ",");		break;	case 'f':		Bputc(&stdout, verb);		range(a, b, " ");		break;	case 'c':	case 'a':		if(nchanges%1024 == 0)			changes = erealloc(changes, (nchanges+1024)*sizeof(changes[0]));		ch = &changes[nchanges++];		ch->a = a;		ch->b = b;		ch->c = c;		ch->d = d;		return;	}	Bputc(&stdout, '\n');	if (mode == 0 || mode == 'n') {		fetch(ixold, a, b, input[0], "< ");		if (a <= b && c <= d)			Bprint(&stdout, "---\n");	}	fetch(ixnew, c, d, input[1], mode == 0 || mode == 'n' ? "> ": "");	if (mode != 0 && mode != 'n' && c <= d)		Bprint(&stdout, ".\n");} enum{	Lines = 3,	/* number of lines of context shown */}; intchangeset(int i){	while(i<nchanges && changes[i].b+1+2*Lines > changes[i+1].a)		i++;	if(i<nchanges)		return i+1;	return nchanges;} voidflushchanges(void){	int a, b, c, d, at;	int i, j; 	if(nchanges == 0)		return;		for(i=0; i<nchanges; ){		j = changeset(i);		a = changes[i].a-Lines;		b = changes[j-1].b+Lines;		c = changes[i].c-Lines;		d = changes[j-1].d+Lines;		if(a < 1)			a = 1;		if(c < 1)			c = 1;		if(b > len[0])			b = len[0];		if(d > len[1])			d = len[1];		if(mode == 'a'){			a = 1;			b = len[0];			c = 1;			d = len[1];			j = nchanges;		}		Bprint(&stdout, "%s:", file1);		range(a, b, ",");		Bprint(&stdout, " - ");		Bprint(&stdout, "%s:", file2);		range(c, d, ",");		Bputc(&stdout, '\n');		at = a;		for(; i<j; i++){			fetch(ixold, at, changes[i].a-1, input[0], "  ");			fetch(ixold, changes[i].a, changes[i].b, input[0], "- ");			fetch(ixnew, changes[i].c, changes[i].d, input[1], "+ ");			at = changes[i].b+1;		}		fetch(ixold, at, b, input[0], "  ");	}	nchanges = 0;}