Mercurial > hg > gitserve

comparison mercurial/bdiff.c @ 433:79c694462294

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Add bdiff.blocks / minor performance tweaks -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Add bdiff.blocks / minor performance tweaks This refactors bdiff.bdiff so that we can get a list of matching blocks of line numbers for use by annotate/unidiff. Minor performance tweaks: - - add a field for equivalence so we can keep h around a bit longer for cmp - - mix len into the hash to reduce collisions - - move an operation into the slow path in longest_match manifest hash: b1aee590b6291b31069ea8a86b6aa8fb259ac244 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (GNU/Linux) iD8DBQFCubu2ywK+sNU5EO8RAm4FAJ9r10aJpT7qA96nqGYFHcuy4XcIHgCfeFx5 q0PyTXeZQc7Fw5kwEPcoykI= =QXSb -----END PGP SIGNATURE-----
author mpm@selenic.com
date Wed, 22 Jun 2005 11:27:50 -0800
parents 9e9f7ab43ce2
children e731d25ddab2
comparison
equal deleted inserted replaced
432:3b9e3d3d2810 433:79c694462294
28 #include <netinet/in.h> 28 #include <netinet/in.h>
29 #include <sys/types.h> 29 #include <sys/types.h>
30 #endif 30 #endif
31 31
32 struct line { 32 struct line {
33 int h, len, n; 33 int h, len, n, e;
34 const char *l; 34 const char *l;
35 }; 35 };
36 36
37 struct hunk { 37 struct hunk {
38 int a1, a2, b1, b2; 38 int a1, a2, b1, b2;
67 h = 0; 67 h = 0;
68 for (p = a; p < a + len; p++) { 68 for (p = a; p < a + len; p++) {
69 h = *p + rol32(h, 7); /* a simple hash from GNU diff */ 69 h = *p + rol32(h, 7); /* a simple hash from GNU diff */
70 if (*p == '\n' || p == a + len - 1) { 70 if (*p == '\n' || p == a + len - 1) {
71 l->len = p - b + 1; 71 l->len = p - b + 1;
72 l->h = h; 72 l->h = h * l->len;
73 l->l = b; 73 l->l = b;
74 l->n = -1; 74 l->n = -1;
75 l++; 75 l++;
76 b = p + 1; 76 b = p + 1;
77 h = 0; 77 h = 0;
84 return i - 1; 84 return i - 1;
85 } 85 }
86 86
87 int inline cmp(struct line *a, struct line *b) 87 int inline cmp(struct line *a, struct line *b)
88 { 88 {
89 return a->len != b->len || memcmp(a->l, b->l, a->len); 89 return a->h != b->h || a->len != b->len || memcmp(a->l, b->l, a->len);
90 } 90 }
91 91
92 static int equatelines(struct line *a, int an, struct line *b, int bn) 92 static int equatelines(struct line *a, int an, struct line *b, int bn)
93 { 93 {
94 int i, j, buckets = 1, t, *h, *l; 94 int i, j, buckets = 1, t, *h, *l;
116 if (!cmp(b + i, b + h[j])) 116 if (!cmp(b + i, b + h[j]))
117 break; 117 break;
118 118
119 /* add to the head of the equivalence class */ 119 /* add to the head of the equivalence class */
120 b[i].n = h[j]; 120 b[i].n = h[j];
121 b[i].h = j; 121 b[i].e = j;
122 h[j] = i; 122 h[j] = i;
123 l[j]++; /* keep track of popularity */ 123 l[j]++; /* keep track of popularity */
124 } 124 }
125 125
126 /* compute popularity threshold */ 126 /* compute popularity threshold */
131 /* find the equivalence class */ 131 /* find the equivalence class */
132 for (j = a[i].h & buckets; h[j] != -1; j = (j + 1) & buckets) 132 for (j = a[i].h & buckets; h[j] != -1; j = (j + 1) & buckets)
133 if (!cmp(a + i, b + h[j])) 133 if (!cmp(a + i, b + h[j]))
134 break; 134 break;
135 135
136 a[i].h = j; /* use equivalence class for quick compare */ 136 a[i].e = j; /* use equivalence class for quick compare */
137 if(l[j] <= t) 137 if(l[j] <= t)
138 a[i].n = h[j]; /* point to head of match list */ 138 a[i].n = h[j]; /* point to head of match list */
139 else 139 else
140 a[i].n = -1; /* too popular */ 140 a[i].n = -1; /* too popular */
141 } 141 }
157 ; 157 ;
158 158
159 /* loop through all lines match a[i] in b */ 159 /* loop through all lines match a[i] in b */
160 for (; j != -1 && j < b2; j = b[j].n) { 160 for (; j != -1 && j < b2; j = b[j].n) {
161 /* does this extend an earlier match? */ 161 /* does this extend an earlier match? */
162 if (i > a1 && j > b1 && jpos[j - 1] == i) 162 if (i > a1 && j > b1 && jpos[j - 1] == i - 1)
163 k = jlen[j - 1] + 1; 163 k = jlen[j - 1] + 1;
164 else 164 else
165 k = 1; 165 k = 1;
166 jpos[j] = i + 1; 166 jpos[j] = i;
167 jlen[j] = k; 167 jlen[j] = k;
168 168
169 /* best match so far? */ 169 /* best match so far? */
170 if (k > mk) { 170 if (k > mk) {
171 mi = i; 171 mi = i;
180 mj = mj - mk + 1; 180 mj = mj - mk + 1;
181 } 181 }
182 182
183 /* expand match to include neighboring popular lines */ 183 /* expand match to include neighboring popular lines */
184 while (mi - mb > a1 && mj - mb > b1 && 184 while (mi - mb > a1 && mj - mb > b1 &&
185 a[mi - mb - 1].h == b[mj - mb - 1].h) 185 a[mi - mb - 1].e == b[mj - mb - 1].e)
186 mb++; 186 mb++;
187 while (mi + mk < a2 && mj + mk < b2 && 187 while (mi + mk < a2 && mj + mk < b2 &&
188 a[mi + mk].h == b[mj + mk].h) 188 a[mi + mk].e == b[mj + mk].e)
189 mk++; 189 mk++;
190 190
191 *omi = mi - mb; 191 *omi = mi - mb;
192 *omj = mj - mb; 192 *omj = mj - mb;
193 return mk + mb; 193 return mk + mb;
211 l->head->b2 = j + k; 211 l->head->b2 = j + k;
212 l->head++; 212 l->head++;
213 recurse(a, b, jpos, jlen, i + k, a2, j + k, b2, l); 213 recurse(a, b, jpos, jlen, i + k, a2, j + k, b2, l);
214 } 214 }
215 215
216 static PyObject *bdiff(PyObject *self, PyObject *args) 216 static struct hunklist diff(struct line *a, int an, struct line *b, int bn)
217 { 217 {
218 PyObject *sa, *sb, *result = NULL;
219 struct hunklist l; 218 struct hunklist l;
220 struct hunk *h; 219 int *jpos, *jlen, t;
221 struct line *al, *bl;
222 char encode[12], *rb;
223 int an, bn, len = 0, t, la = 0, lb = 0, *jpos, *jlen;
224
225 if (!PyArg_ParseTuple(args, "SS:bdiff", &sa, &sb))
226 return NULL;
227 220
228 /* allocate and fill arrays */ 221 /* allocate and fill arrays */
229 an = splitlines(PyString_AsString(sa), PyString_Size(sa), &al); 222 t = equatelines(a, an, b, bn);
230 bn = splitlines(PyString_AsString(sb), PyString_Size(sb), &bl);
231 t = equatelines(al, an, bl, bn);
232 jpos = calloc(bn, sizeof(int)); 223 jpos = calloc(bn, sizeof(int));
233 jlen = calloc(bn, sizeof(int)); 224 jlen = calloc(bn, sizeof(int));
234 l.head = l.base = malloc(sizeof(struct hunk) * ((an + bn) / 4 + 2)); 225 l.head = l.base = malloc(sizeof(struct hunk) * ((an + bn) / 4 + 2));
235 if (!al || !bl || !jpos || !jlen || !l.base || !t) 226
236 goto nomem; 227 if (jpos && jlen && l.base && t) {
237 228 /* generate the matching block list */
238 /* generate the matching block list */ 229 recurse(a, b, jpos, jlen, 0, an, 0, bn, &l);
239 recurse(al, bl, jpos, jlen, 0, an, 0, bn, &l); 230 l.head->a1 = an;
240 l.head->a1 = an; 231 l.head->b1 = bn;
241 l.head->b1 = bn; 232 l.head++;
242 l.head++; 233 }
234
235 free(jpos);
236 free(jlen);
237 return l;
238 }
239
240 static PyObject *blocks(PyObject *self, PyObject *args)
241 {
242 PyObject *sa, *sb, *rl, *m;
243 struct line *a, *b;
244 struct hunklist l;
245 struct hunk *h;
246 int an, bn, pos = 0;
247
248 if (!PyArg_ParseTuple(args, "SS:bdiff", &sa, &sb))
249 return NULL;
250
251 an = splitlines(PyString_AsString(sa), PyString_Size(sa), &a);
252 bn = splitlines(PyString_AsString(sb), PyString_Size(sb), &b);
253 if (!a || !b)
254 goto nomem;
255
256 l = diff(a, an, b, bn);
257 rl = PyList_New(l.head - l.base);
258 if (!l.head || !rl)
259 goto nomem;
260
261 for(h = l.base; h != l.head; h++) {
262 m = Py_BuildValue("iiii", h->a1, h->a2, h->b1, h->b2);
263 PyList_SetItem(rl, pos, m);
264 pos++;
265 }
266
267 nomem:
268 free(a);
269 free(b);
270 free(l.base);
271 return rl ? rl : PyErr_NoMemory();
272 }
273
274 static PyObject *bdiff(PyObject *self, PyObject *args)
275 {
276 PyObject *sa, *sb, *result = NULL;
277 struct line *al, *bl;
278 struct hunklist l;
279 struct hunk *h;
280 char encode[12], *rb;
281 int an, bn, len = 0, la = 0, lb = 0;
282
283 if (!PyArg_ParseTuple(args, "SS:bdiff", &sa, &sb))
284 return NULL;
285
286 an = splitlines(PyString_AsString(sa), PyString_Size(sa), &al);
287 bn = splitlines(PyString_AsString(sb), PyString_Size(sb), &bl);
288 if (!al || !bl)
289 goto nomem;
290
291 l = diff(al, an, bl, bn);
292 if (!l.head)
293 goto nomem;
243 294
244 /* calculate length of output */ 295 /* calculate length of output */
245 for(h = l.base; h != l.head; h++) { 296 for(h = l.base; h != l.head; h++) {
246 if (h->a1 != la || h->b1 != lb) 297 if (h->a1 != la || h->b1 != lb)
247 len += 12 + bl[h->b1].l - bl[lb].l; 298 len += 12 + bl[h->b1].l - bl[lb].l;
272 } 323 }
273 324
274 nomem: 325 nomem:
275 free(al); 326 free(al);
276 free(bl); 327 free(bl);
277 free(jpos);
278 free(jlen);
279 free(l.base); 328 free(l.base);
280 return result ? result : PyErr_NoMemory(); 329 return result ? result : PyErr_NoMemory();
281 } 330 }
282 331
283 static char mdiff_doc[] = "Efficient binary diff."; 332 static char mdiff_doc[] = "Efficient binary diff.";
284 333
285 static PyMethodDef methods[] = { 334 static PyMethodDef methods[] = {
286 {"bdiff", bdiff, METH_VARARGS, "calculate a binary diff\n"}, 335 {"bdiff", bdiff, METH_VARARGS, "calculate a binary diff\n"},
336 {"blocks", blocks, METH_VARARGS, "find a list of matching lines\n"},
287 {NULL, NULL} 337 {NULL, NULL}
288 }; 338 };
289 339
290 PyMODINIT_FUNC initbdiff(void) 340 PyMODINIT_FUNC initbdiff(void)
291 { 341 {