diffio.c - 9base - revived minimalist port of Plan 9 userland to Unix
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diffio.c (6620B)
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1 #include <u.h>
2 #include <libc.h>
3 #include <bio.h>
4 #include <ctype.h>
5 #include "diff.h"
6
7 struct line {
8 int serial;
9 int value;
10 };
11 extern struct line *file[2];
12 extern int len[2];
13 extern long *ixold, *ixnew;
14 extern int *J;
15
16 static Biobuf *input[2];
17 static char *file1, *file2;
18 static int firstchange;
19
20 #define MAXLINELEN 4096
21 #define MIN(x, y) ((x) < (y) ? (x): (y))
22
23 static int
24 readline(Biobuf *bp, char *buf)
25 {
26 int c;
27 char *p, *e;
28
29 p = buf;
30 e = p + MAXLINELEN-1;
31 do {
32 c = Bgetc(bp);
33 if (c < 0) {
34 if (p == buf)
35 return -1;
36 break;
37 }
38 if (c == '\n')
39 break;
40 *p++ = c;
41 } while (p < e);
42 *p = 0;
43 if (c != '\n' && c >= 0) {
44 do c = Bgetc(bp);
45 while (c >= 0 && c != '\n');
46 }
47 return p - buf;
48 }
49
50 #define HALFLONG 16
51 #define low(x) (x&((1L<<HALFLONG)-1))
52 #define high(x) (x>>HALFLONG)
53
54 /*
55 * hashing has the effect of
56 * arranging line in 7-bit bytes and then
57 * summing 1-s complement in 16-bit hunks
58 */
59 static int
60 readhash(Biobuf *bp, char *buf)
61 {
62 long sum;
63 unsigned shift;
64 char *p;
65 int len, space;
66
67 sum = 1;
68 shift = 0;
69 if ((len = readline(bp, buf)) == -1)
70 return 0;
71 p = buf;
72 switch(bflag) /* various types of white space handling */
73 {
74 case 0:
75 while (len--) {
76 sum += (long)*p++ << (shift &= (HALFLONG-1));
77 shift += 7;
78 }
79 break;
80 case 1:
81 /*
82 * coalesce multiple white-space
83 */
84 for (space = 0; len--; p++) {
85 if (isspace((uchar)*p)) {
86 space++;
87 continue;
88 }
89 if (space) {
90 shift += 7;
91 space = 0;
92 }
93 sum += (long)*p << (shift &= (HALFLONG-1));
94 shift += 7;
95 }
96 break;
97 default:
98 /*
99 * strip all white-space
100 */
101 while (len--) {
102 if (isspace((uchar)*p)) {
103 p++;
104 continue;
105 }
106 sum += (long)*p++ << (shift &= (HALFLONG-1));
107 shift += 7;
108 }
109 break;
110 }
111 sum = low(sum) + high(sum);
112 return ((short)low(sum) + (short)high(sum));
113 }
114
115 Biobuf *
116 prepare(int i, char *arg)
117 {
118 struct line *p;
119 int j, h;
120 Biobuf *bp;
121 char *cp, buf[MAXLINELEN];
122 int nbytes;
123 Rune r;
124
125 bp = Bopen(arg, OREAD);
126 if (!bp) {
127 panic(mflag ? 0: 2, "cannot open %s: %r\n", arg);
128 return 0;
129 }
130 if (binary)
131 return bp;
132 nbytes = Bread(bp, buf, MIN(1024, MAXLINELEN));
133 if (nbytes > 0) {
134 cp = buf;
135 while (cp < buf+nbytes-UTFmax) {
136 /*
137 * heuristic for a binary file in the
138 * brave new UNICODE world
139 */
140 cp += chartorune(&r, cp);
141 if (r == 0 || (r > 0x7f && r <= 0xa0)) {
142 binary++;
143 return bp;
144 }
145 }
146 Bseek(bp, 0, 0);
147 }
148 p = MALLOC(struct line, 3);
149 for (j = 0; h = readhash(bp, buf); p[j].value = h)
150 p = REALLOC(p, struct line, (++j+3));
151 len[i] = j;
152 file[i] = p;
153 input[i] = bp; /*fix*/
154 if (i == 0) { /*fix*/
155 file1 = arg;
156 firstchange = 0;
157 }
158 else
159 file2 = arg;
160 return bp;
161 }
162
163 static int
164 squishspace(char *buf)
165 {
166 char *p, *q;
167 int space;
168
169 for (space = 0, q = p = buf; *q; q++) {
170 if (isspace((uchar)*q)) {
171 space++;
172 continue;
173 }
174 if (space && bflag == 1) {
175 *p++ = ' ';
176 space = 0;
177 }
178 *p++ = *q;
179 }
180 *p = 0;
181 return p - buf;
182 }
183
184 /*
185 * need to fix up for unexpected EOF's
186 */
187 void
188 check(Biobuf *bf, Biobuf *bt)
189 {
190 int f, t, flen, tlen;
191 char fbuf[MAXLINELEN], tbuf[MAXLINELEN];
192
193 ixold[0] = ixnew[0] = 0;
194 for (f = t = 1; f < len[0]; f++) {
195 flen = readline(bf, fbuf);
196 ixold[f] = ixold[f-1] + flen + 1; /* ftell(bf) */
197 if (J[f] == 0)
198 continue;
199 do {
200 tlen = readline(bt, tbuf);
201 ixnew[t] = ixnew[t-1] + tlen + 1; /* ftell(bt) */
202 } while (t++ < J[f]);
203 if (bflag) {
204 flen = squishspace(fbuf);
205 tlen = squishspace(tbuf);
206 }
207 if (flen != tlen || strcmp(fbuf, tbuf))
208 J[f] = 0;
209 }
210 while (t < len[1]) {
211 tlen = readline(bt, tbuf);
212 ixnew[t] = ixnew[t-1] + tlen + 1; /* fseek(bt) */
213 t++;
214 }
215 }
216
217 static void
218 range(int a, int b, char *separator)
219 {
220 Bprint(&stdout, "%d", a > b ? b: a);
221 if (a < b)
222 Bprint(&stdout, "%s%d", separator, b);
223 }
224
225 static void
226 fetch(long *f, int a, int b, Biobuf *bp, char *s)
227 {
228 char buf[MAXLINELEN];
229 int maxb;
230
231 if(a <= 1)
232 a = 1;
233 if(bp == input[0])
234 maxb = len[0];
235 else
236 maxb = len[1];
237 if(b > maxb)
238 b = maxb;
239 if(a > maxb)
240 return;
241 Bseek(bp, f[a-1], 0);
242 while (a++ <= b) {
243 readline(bp, buf);
244 Bprint(&stdout, "%s%s\n", s, buf);
245 }
246 }
247
248 typedef struct Change Change;
249 struct Change
250 {
251 int a;
252 int b;
253 int c;
254 int d;
255 };
256
257 Change *changes;
258 int nchanges;
259
260 void
261 change(int a, int b, int c, int d)
262 {
263 char verb;
264 char buf[4];
265 Change *ch;
266
267 if (a > b && c > d)
268 return;
269 anychange = 1;
270 if (mflag && firstchange == 0) {
271 if(mode) {
272 buf[0] = '-';
273 buf[1] = mode;
274 buf[2] = ' ';
275 buf[3] = '\0';
276 } else {
277 buf[0] = '\0';
278 }
279 Bprint(&stdout, "diff %s%s %s\n", buf, file1, file2);
280 firstchange = 1;
281 }
282 verb = a > b ? 'a': c > d ? 'd': 'c';
283 switch(mode) {
284 case 'e':
285 range(a, b, ",");
286 Bputc(&stdout, verb);
287 break;
288 case 0:
289 range(a, b, ",");
290 Bputc(&stdout, verb);
291 range(c, d, ",");
292 break;
293 case 'n':
294 Bprint(&stdout, "%s:", file1);
295 range(a, b, ",");
296 Bprint(&stdout, " %c ", verb);
297 Bprint(&stdout, "%s:", file2);
298 range(c, d, ",");
299 break;
300 case 'f':
301 Bputc(&stdout, verb);
302 range(a, b, " ");
303 break;
304 case 'c':
305 case 'a':
306 if(nchanges%1024 == 0)
307 changes = erealloc(changes, (nchanges+1024)*sizeof(changes[0]));
308 ch = &changes[nchanges++];
309 ch->a = a;
310 ch->b = b;
311 ch->c = c;
312 ch->d = d;
313 return;
314 }
315 Bputc(&stdout, '\n');
316 if (mode == 0 || mode == 'n') {
317 fetch(ixold, a, b, input[0], "< ");
318 if (a <= b && c <= d)
319 Bprint(&stdout, "---\n");
320 }
321 fetch(ixnew, c, d, input[1], mode == 0 || mode == 'n' ? "> ": "");
322 if (mode != 0 && mode != 'n' && c <= d)
323 Bprint(&stdout, ".\n");
324 }
325
326 enum
327 {
328 Lines = 3 /* number of lines of context shown */
329 };
330
331 int
332 changeset(int i)
333 {
334 while(i<nchanges && changes[i].b+1+2*Lines > changes[i+1].a)
335 i++;
336 if(i<nchanges)
337 return i+1;
338 return nchanges;
339 }
340
341 void
342 flushchanges(void)
343 {
344 int a, b, c, d, at;
345 int i, j;
346
347 if(nchanges == 0)
348 return;
349
350 for(i=0; i<nchanges; ){
351 j = changeset(i);
352 a = changes[i].a-Lines;
353 b = changes[j-1].b+Lines;
354 c = changes[i].c-Lines;
355 d = changes[j-1].d+Lines;
356 if(a < 1)
357 a = 1;
358 if(c < 1)
359 c = 1;
360 if(b > len[0])
361 b = len[0];
362 if(d > len[1])
363 d = len[1];
364 if(mode == 'a'){
365 a = 1;
366 b = len[0];
367 c = 1;
368 d = len[1];
369 j = nchanges;
370 }
371 Bprint(&stdout, "%s:", file1);
372 range(a, b, ",");
373 Bprint(&stdout, " - ");
374 Bprint(&stdout, "%s:", file2);
375 range(c, d, ",");
376 Bputc(&stdout, '\n');
377 at = a;
378 for(; i<j; i++){
379 fetch(ixold, at, changes[i].a-1, input[0], " ");
380 fetch(ixold, changes[i].a, changes[i].b, input[0], "- ");
381 fetch(ixnew, changes[i].c, changes[i].d, input[1], "+ ");
382 at = changes[i].b+1;
383 }
384 fetch(ixold, at, b, input[0], " ");
385 }
386 nchanges = 0;
387 }