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comparison src/xdiff/xhistogram.c @ 14696:195e8b1fcbbf v8.1.0360

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patch 8.1.0360: using an external diff program is slow and inflexible commit https://github.com/vim/vim/commit/e828b7621cf9065a3582be0c4dd1e0e846e335bf Author: Bram Moolenaar <Bram@vim.org> Date: Mon Sep 10 17:51:58 2018 +0200 patch 8.1.0360: using an external diff program is slow and inflexible Problem: Using an external diff program is slow and inflexible. Solution: Include the xdiff library. (Christian Brabandt, closes https://github.com/vim/vim/issues/2732) Use it by default.
author Christian Brabandt <cb@256bit.org>
date Mon, 10 Sep 2018 18:00:06 +0200
parents
children 3be01cf0a632
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14695:b178e2039b2d 14696:195e8b1fcbbf
1 /*
2 * Copyright (C) 2010, Google Inc.
3 * and other copyright owners as documented in JGit's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 #include "xinclude.h"
45 #include "xtypes.h"
46 #include "xdiff.h"
47
48 #define MAX_PTR INT_MAX
49 #define MAX_CNT INT_MAX
50
51 #define LINE_END(n) (line##n + count##n - 1)
52 #define LINE_END_PTR(n) (*line##n + *count##n - 1)
53
54 struct histindex {
55 struct record {
56 unsigned int ptr, cnt;
57 struct record *next;
58 } **records, /* an occurrence */
59 **line_map; /* map of line to record chain */
60 chastore_t rcha;
61 unsigned int *next_ptrs;
62 unsigned int table_bits,
63 records_size,
64 line_map_size;
65
66 unsigned int max_chain_length,
67 key_shift,
68 ptr_shift;
69
70 unsigned int cnt,
71 has_common;
72
73 xdfenv_t *env;
74 xpparam_t const *xpp;
75 };
76
77 struct region {
78 unsigned int begin1, end1;
79 unsigned int begin2, end2;
80 };
81
82 #define LINE_MAP(i, a) (i->line_map[(a) - i->ptr_shift])
83
84 #define NEXT_PTR(index, ptr) \
85 (index->next_ptrs[(ptr) - index->ptr_shift])
86
87 #define CNT(index, ptr) \
88 ((LINE_MAP(index, ptr))->cnt)
89
90 #define REC(env, s, l) \
91 (env->xdf##s.recs[l - 1])
92
93 static int cmp_recs(xpparam_t const *xpp,
94 xrecord_t *r1, xrecord_t *r2)
95 {
96 return r1->ha == r2->ha &&
97 xdl_recmatch(r1->ptr, r1->size, r2->ptr, r2->size,
98 xpp->flags);
99 }
100
101 #define CMP_ENV(xpp, env, s1, l1, s2, l2) \
102 (cmp_recs(xpp, REC(env, s1, l1), REC(env, s2, l2)))
103
104 #define CMP(i, s1, l1, s2, l2) \
105 (cmp_recs(i->xpp, REC(i->env, s1, l1), REC(i->env, s2, l2)))
106
107 #define TABLE_HASH(index, side, line) \
108 XDL_HASHLONG((REC(index->env, side, line))->ha, index->table_bits)
109
110 static int scanA(struct histindex *index, int line1, int count1)
111 {
112 int ptr, tbl_idx;
113 unsigned int chain_len;
114 struct record **rec_chain, *rec;
115
116 for (ptr = LINE_END(1); line1 <= ptr; ptr--) {
117 tbl_idx = TABLE_HASH(index, 1, ptr);
118 rec_chain = index->records + tbl_idx;
119 rec = *rec_chain;
120
121 chain_len = 0;
122 while (rec) {
123 if (CMP(index, 1, rec->ptr, 1, ptr)) {
124 /*
125 * ptr is identical to another element. Insert
126 * it onto the front of the existing element
127 * chain.
128 */
129 NEXT_PTR(index, ptr) = rec->ptr;
130 rec->ptr = ptr;
131 /* cap rec->cnt at MAX_CNT */
132 rec->cnt = XDL_MIN(MAX_CNT, rec->cnt + 1);
133 LINE_MAP(index, ptr) = rec;
134 goto continue_scan;
135 }
136
137 rec = rec->next;
138 chain_len++;
139 }
140
141 if (chain_len == index->max_chain_length)
142 return -1;
143
144 /*
145 * This is the first time we have ever seen this particular
146 * element in the sequence. Construct a new chain for it.
147 */
148 if (!(rec = xdl_cha_alloc(&index->rcha)))
149 return -1;
150 rec->ptr = ptr;
151 rec->cnt = 1;
152 rec->next = *rec_chain;
153 *rec_chain = rec;
154 LINE_MAP(index, ptr) = rec;
155
156 continue_scan:
157 ; /* no op */
158 }
159
160 return 0;
161 }
162
163 static int try_lcs(struct histindex *index, struct region *lcs, int b_ptr,
164 int line1, int count1, int line2, int count2)
165 {
166 unsigned int b_next = b_ptr + 1;
167 struct record *rec = index->records[TABLE_HASH(index, 2, b_ptr)];
168 unsigned int as, ae, bs, be, np, rc;
169 int should_break;
170
171 for (; rec; rec = rec->next) {
172 if (rec->cnt > index->cnt) {
173 if (!index->has_common)
174 index->has_common = CMP(index, 1, rec->ptr, 2, b_ptr);
175 continue;
176 }
177
178 as = rec->ptr;
179 if (!CMP(index, 1, as, 2, b_ptr))
180 continue;
181
182 index->has_common = 1;
183 for (;;) {
184 should_break = 0;
185 np = NEXT_PTR(index, as);
186 bs = b_ptr;
187 ae = as;
188 be = bs;
189 rc = rec->cnt;
190
191 while (line1 < (int)as && line2 < (int)bs
192 && CMP(index, 1, as - 1, 2, bs - 1)) {
193 as--;
194 bs--;
195 if (1 < rc)
196 rc = XDL_MIN(rc, CNT(index, as));
197 }
198 while ((int)ae < LINE_END(1) && (int)be < LINE_END(2)
199 && CMP(index, 1, ae + 1, 2, be + 1)) {
200 ae++;
201 be++;
202 if (1 < rc)
203 rc = XDL_MIN(rc, CNT(index, ae));
204 }
205
206 if (b_next <= be)
207 b_next = be + 1;
208 if (lcs->end1 - lcs->begin1 < ae - as || rc < index->cnt) {
209 lcs->begin1 = as;
210 lcs->begin2 = bs;
211 lcs->end1 = ae;
212 lcs->end2 = be;
213 index->cnt = rc;
214 }
215
216 if (np == 0)
217 break;
218
219 while (np <= ae) {
220 np = NEXT_PTR(index, np);
221 if (np == 0) {
222 should_break = 1;
223 break;
224 }
225 }
226
227 if (should_break)
228 break;
229
230 as = np;
231 }
232 }
233 return b_next;
234 }
235
236 static int fall_back_to_classic_diff(xpparam_t const *xpp, xdfenv_t *env,
237 int line1, int count1, int line2, int count2)
238 {
239 xpparam_t xpparam;
240 xpparam.flags = xpp->flags & ~XDF_DIFF_ALGORITHM_MASK;
241
242 return xdl_fall_back_diff(env, &xpparam,
243 line1, count1, line2, count2);
244 }
245
246 static inline void free_index(struct histindex *index)
247 {
248 xdl_free(index->records);
249 xdl_free(index->line_map);
250 xdl_free(index->next_ptrs);
251 xdl_cha_free(&index->rcha);
252 }
253
254 static int find_lcs(xpparam_t const *xpp, xdfenv_t *env,
255 struct region *lcs,
256 int line1, int count1, int line2, int count2)
257 {
258 int b_ptr;
259 int sz, ret = -1;
260 struct histindex index;
261
262 memset(&index, 0, sizeof(index));
263
264 index.env = env;
265 index.xpp = xpp;
266
267 index.records = NULL;
268 index.line_map = NULL;
269 /* in case of early xdl_cha_free() */
270 index.rcha.head = NULL;
271
272 index.table_bits = xdl_hashbits(count1);
273 sz = index.records_size = 1 << index.table_bits;
274 sz *= sizeof(struct record *);
275 if (!(index.records = (struct record **) xdl_malloc(sz)))
276 goto cleanup;
277 memset(index.records, 0, sz);
278
279 sz = index.line_map_size = count1;
280 sz *= sizeof(struct record *);
281 if (!(index.line_map = (struct record **) xdl_malloc(sz)))
282 goto cleanup;
283 memset(index.line_map, 0, sz);
284
285 sz = index.line_map_size;
286 sz *= sizeof(unsigned int);
287 if (!(index.next_ptrs = (unsigned int *) xdl_malloc(sz)))
288 goto cleanup;
289 memset(index.next_ptrs, 0, sz);
290
291 /* lines / 4 + 1 comes from xprepare.c:xdl_prepare_ctx() */
292 if (xdl_cha_init(&index.rcha, sizeof(struct record), count1 / 4 + 1) < 0)
293 goto cleanup;
294
295 index.ptr_shift = line1;
296 index.max_chain_length = 64;
297
298 if (scanA(&index, line1, count1))
299 goto cleanup;
300
301 index.cnt = index.max_chain_length + 1;
302
303 for (b_ptr = line2; b_ptr <= LINE_END(2); )
304 b_ptr = try_lcs(&index, lcs, b_ptr, line1, count1, line2, count2);
305
306 if (index.has_common && index.max_chain_length < index.cnt)
307 ret = 1;
308 else
309 ret = 0;
310
311 cleanup:
312 free_index(&index);
313 return ret;
314 }
315
316 static int histogram_diff(xpparam_t const *xpp, xdfenv_t *env,
317 int line1, int count1, int line2, int count2)
318 {
319 struct region lcs;
320 int lcs_found;
321 int result;
322 redo:
323 result = -1;
324
325 if (count1 <= 0 && count2 <= 0)
326 return 0;
327
328 if (LINE_END(1) >= MAX_PTR)
329 return -1;
330
331 if (!count1) {
332 while(count2--)
333 env->xdf2.rchg[line2++ - 1] = 1;
334 return 0;
335 } else if (!count2) {
336 while(count1--)
337 env->xdf1.rchg[line1++ - 1] = 1;
338 return 0;
339 }
340
341 memset(&lcs, 0, sizeof(lcs));
342 lcs_found = find_lcs(xpp, env, &lcs, line1, count1, line2, count2);
343 if (lcs_found < 0)
344 goto out;
345 else if (lcs_found)
346 result = fall_back_to_classic_diff(xpp, env, line1, count1, line2, count2);
347 else {
348 if (lcs.begin1 == 0 && lcs.begin2 == 0) {
349 while (count1--)
350 env->xdf1.rchg[line1++ - 1] = 1;
351 while (count2--)
352 env->xdf2.rchg[line2++ - 1] = 1;
353 result = 0;
354 } else {
355 result = histogram_diff(xpp, env,
356 line1, lcs.begin1 - line1,
357 line2, lcs.begin2 - line2);
358 if (result)
359 goto out;
360 /*
361 * result = histogram_diff(xpp, env,
362 * lcs.end1 + 1, LINE_END(1) - lcs.end1,
363 * lcs.end2 + 1, LINE_END(2) - lcs.end2);
364 * but let's optimize tail recursion ourself:
365 */
366 count1 = LINE_END(1) - lcs.end1;
367 line1 = lcs.end1 + 1;
368 count2 = LINE_END(2) - lcs.end2;
369 line2 = lcs.end2 + 1;
370 goto redo;
371 }
372 }
373 out:
374 return result;
375 }
376
377 int xdl_do_histogram_diff(mmfile_t *file1, mmfile_t *file2,
378 xpparam_t const *xpp, xdfenv_t *env)
379 {
380 if (xdl_prepare_env(file1, file2, xpp, env) < 0)
381 return -1;
382
383 return histogram_diff(xpp, env,
384 env->xdf1.dstart + 1, env->xdf1.dend - env->xdf1.dstart + 1,
385 env->xdf2.dstart + 1, env->xdf2.dend - env->xdf2.dstart + 1);
386 }