#include <u.h>#include <libc.h>#include <bio.h>#include <ctype.h>#include "diff.h" #define MIN(x, y)	((x) < (y) ? (x): (y)) intreadline(Biobuf *bp, char *buf, int nbuf){	int c;	char *p, *e; 	p = buf;	e = p + nbuf-1;	do {		c = Bgetc(bp);		if (c < 0) {			if (p == buf)				return -1;			break;		}		*p++ = c;		if (c == '\n')			break;	} 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, int nbuf){	long sum;	unsigned shift;	char *p;	int len, space; 	sum = 1;	shift = 0;	if ((len = readline(bp, buf, nbuf)) == -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(Diff *d, int i, char *arg, char *orig){	Line *p;	int j, h;	Biobuf *bp;	char *cp, buf[MAXLINELEN];	int nbytes;	Rune r; 	if (i == 0) {		d->file1 = orig;		d->firstchange = 0;	} else		d->file2 = orig;	bp = Bopen(arg, OREAD);	if (!bp)		sysfatal("cannot open %s: %r", arg);	if (d->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)) {				d->binary++;				return bp;			}		}		Bseek(bp, 0, 0);	}	p = emalloc(3*sizeof(Line));	for (j = 0; h = readhash(bp, buf, sizeof(buf)); p[j].value = h)		p = erealloc(p, (++j+3)*sizeof(Line));	d->len[i] = j;	d->file[i] = p;	d->input[i] = bp;	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(Diff *d, Biobuf *bf, Biobuf *bt){	int f, t, flen, tlen;	char fbuf[MAXLINELEN], tbuf[MAXLINELEN]; 	d->ixold[0] = 0;	d->ixnew[0] = 0;	for (f = t = 1; f < d->len[0]; f++) {		flen = readline(bf, fbuf, sizeof(fbuf));		d->ixold[f] = d->ixold[f-1] + flen;		/* ftell(bf) */		if (d->J[f] == 0)			continue;		do {			tlen = readline(bt, tbuf, sizeof(tbuf));			d->ixnew[t] = d->ixnew[t-1] + tlen;	/* ftell(bt) */		} while (t++ < d->J[f]);		if (bflag) {			flen = squishspace(fbuf);			tlen = squishspace(tbuf);		}		if (flen != tlen || strcmp(fbuf, tbuf))			d->J[f] = 0;	}	while (t < d->len[1]) {		tlen = readline(bt, tbuf, sizeof(tbuf));		d->ixnew[t] = d->ixnew[t-1] + tlen;	/* 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);} voidfetch(Diff *d, long *f, int a, int b, Biobuf *bp, char *s){	char buf[MAXLINELEN];	int maxb, len; 	if(a <= 1)		a = 1;	if(bp == d->input[0])		maxb = d->len[0];	else		maxb = d->len[1];	if(b > maxb)		b = maxb;	if(a > maxb)		return;	Bseek(bp, f[a-1], 0);	while (a++ <= b) {		len = readline(bp, buf, sizeof(buf));		if(len == 0 || buf[len-1] != '\n'){			Bprint(&stdout, "%s%s\n", s, buf);			Bprint(&stdout, "\\ No newline at end of file\n");		}else			Bprint(&stdout, "%s%s", s, buf);	}} voidchange(Diff *df, 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 && df->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, df->file1, df->file2);		df->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:", df->file1);		range(a, b, ",");		Bprint(&stdout, " %c ", verb);		Bprint(&stdout, "%s:", df->file2);		range(c, d, ",");		break;	case 'f':		Bputc(&stdout, verb);		range(a, b, " ");		break;	case 'c':	case 'a':	case 'u':		if(df->nchanges%1024 == 0)			df->changes = erealloc(df->changes, (df->nchanges+1024)*sizeof(df->changes[0]));		ch = &df->changes[df->nchanges++];		ch->oldx = a;		ch->oldy = b;		ch->newx = c;		ch->newy = d;		return;	}	Bputc(&stdout, '\n');	if (mode == 0 || mode == 'n') {		fetch(df, df->ixold, a, b, df->input[0], "< ");		if (a <= b && c <= d)			Bprint(&stdout, "---\n");	}	fetch(df, df->ixnew, c, d, df->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(Diff *d, int i){	while(i < d->nchanges && d->changes[i].oldy + 1 + 2*Lines > d->changes[i+1].oldx)		i++;	if(i < d->nchanges)		return i+1;	return d->nchanges;} voidflushchanges(Diff *df){	vlong a, b, c, d, at, hdr;	vlong i, j; 	if(df->nchanges == 0)		return; 	hdr = 0;	for(i=0; i < df->nchanges; ){		j = changeset(df, i);		a = df->changes[i].oldx - Lines;		b = df->changes[j-1].oldy + Lines;		c = df->changes[i].newx - Lines;		d = df->changes[j-1].newy + Lines;		if(a < 1)			a = 1;		if(c < 1)			c = 1;		if(b > df->len[0])			b = df->len[0];		if(d > df->len[1])			d = df->len[1];		if(mode == 'a'){			a = 1;			b = df->len[0];			c = 1;			d = df->len[1];			j = df->nchanges;		}		if(mode == 'u'){			if(!hdr){				Bprint(&stdout, "--- %s\n", df->file1);				Bprint(&stdout, "+++ %s\n", df->file2);				hdr = 1;			}			Bprint(&stdout, "@@ -%lld,%lld +%lld,%lld @@\n", a, b-a+1, c, d-c+1);		}else{			Bprint(&stdout, "%s:", df->file1);			range(a, b, ",");			Bprint(&stdout, " - ");			Bprint(&stdout, "%s:", df->file2);			range(c, d, ",");			Bputc(&stdout, '\n');		}		at = a;		for(; i<j; i++){			fetch(df, df->ixold, at, df->changes[i].oldx-1, df->input[0], mode == 'u' ? " " : "  ");			fetch(df, df->ixold, df->changes[i].oldx, df->changes[i].oldy, df->input[0], mode == 'u' ? "-" : "- ");			fetch(df, df->ixnew, df->changes[i].newx, df->changes[i].newy, df->input[1], mode == 'u' ? "+" : "+ ");			at = df->changes[i].oldy+1;		}		fetch(df, df->ixold, at, b, df->input[0], mode == 'u' ? " " : "  ");	}	df->nchanges = 0;}