sys/src/cmd/diff/diffio.c

   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(*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(*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(*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 }