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 /* * LibXDiff by Davide Libenzi ( File Differential Library ) * Copyright (C) 2003 Davide Libenzi * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, see * . * * Davide Libenzi * */ #include "xinclude.h" #define XDL_MAX_COST_MIN 256 #define XDL_HEUR_MIN_COST 256 #define XDL_LINE_MAX (long)((1UL << (CHAR_BIT * sizeof(long) - 1)) - 1) #define XDL_SNAKE_CNT 20 #define XDL_K_HEUR 4 typedef struct s_xdpsplit { long i1, i2; int min_lo, min_hi; } xdpsplit_t; /* * See "An O(ND) Difference Algorithm and its Variations", by Eugene Myers. * Basically considers a "box" (off1, off2, lim1, lim2) and scan from both * the forward diagonal starting from (off1, off2) and the backward diagonal * starting from (lim1, lim2). If the K values on the same diagonal crosses * returns the furthest point of reach. We might encounter expensive edge cases * using this algorithm, so a little bit of heuristic is needed to cut the * search and to return a suboptimal point. */ static long xdl_split(unsigned long const *ha1, long off1, long lim1, unsigned long const *ha2, long off2, long lim2, long *kvdf, long *kvdb, int need_min, xdpsplit_t *spl, xdalgoenv_t *xenv) { long dmin = off1 - lim2, dmax = lim1 - off2; long fmid = off1 - off2, bmid = lim1 - lim2; long odd = (fmid - bmid) & 1; long fmin = fmid, fmax = fmid; long bmin = bmid, bmax = bmid; long ec, d, i1, i2, prev1, best, dd, v, k; /* * Set initial diagonal values for both forward and backward path. */ kvdf[fmid] = off1; kvdb[bmid] = lim1; for (ec = 1;; ec++) { int got_snake = 0; /* * We need to extend the diagonal "domain" by one. If the next * values exits the box boundaries we need to change it in the * opposite direction because (max - min) must be a power of * two. * * Also we initialize the external K value to -1 so that we can * avoid extra conditions in the check inside the core loop. */ if (fmin > dmin) kvdf[--fmin - 1] = -1; else ++fmin; if (fmax < dmax) kvdf[++fmax + 1] = -1; else --fmax; for (d = fmax; d >= fmin; d -= 2) { if (kvdf[d - 1] >= kvdf[d + 1]) i1 = kvdf[d - 1] + 1; else i1 = kvdf[d + 1]; prev1 = i1; i2 = i1 - d; for (; i1 < lim1 && i2 < lim2 && ha1[i1] == ha2[i2]; i1++, i2++); if (i1 - prev1 > xenv->snake_cnt) got_snake = 1; kvdf[d] = i1; if (odd && bmin <= d && d <= bmax && kvdb[d] <= i1) { spl->i1 = i1; spl->i2 = i2; spl->min_lo = spl->min_hi = 1; return ec; } } /* * We need to extend the diagonal "domain" by one. If the next * values exits the box boundaries we need to change it in the * opposite direction because (max - min) must be a power of * two. * * Also we initialize the external K value to -1 so that we can * avoid extra conditions in the check inside the core loop. */ if (bmin > dmin) kvdb[--bmin - 1] = XDL_LINE_MAX; else ++bmin; if (bmax < dmax) kvdb[++bmax + 1] = XDL_LINE_MAX; else --bmax; for (d = bmax; d >= bmin; d -= 2) { if (kvdb[d - 1] < kvdb[d + 1]) i1 = kvdb[d - 1]; else i1 = kvdb[d + 1] - 1; prev1 = i1; i2 = i1 - d; for (; i1 > off1 && i2 > off2 && ha1[i1 - 1] == ha2[i2 - 1]; i1--, i2--); if (prev1 - i1 > xenv->snake_cnt) got_snake = 1; kvdb[d] = i1; if (!odd && fmin <= d && d <= fmax && i1 <= kvdf[d]) { spl->i1 = i1; spl->i2 = i2; spl->min_lo = spl->min_hi = 1; return ec; } } if (need_min) continue; /* * If the edit cost is above the heuristic trigger and if * we got a good snake, we sample current diagonals to see * if some of them have reached an "interesting" path. Our * measure is a function of the distance from the diagonal * corner (i1 + i2) penalized with the distance from the * mid diagonal itself. If this value is above the current * edit cost times a magic factor (XDL_K_HEUR) we consider * it interesting. */ if (got_snake && ec > xenv->heur_min) { for (best = 0, d = fmax; d >= fmin; d -= 2) { dd = d > fmid ? d - fmid: fmid - d; i1 = kvdf[d]; i2 = i1 - d; v = (i1 - off1) + (i2 - off2) - dd; if (v > XDL_K_HEUR * ec && v > best && off1 + xenv->snake_cnt <= i1 && i1 < lim1 && off2 + xenv->snake_cnt <= i2 && i2 < lim2) { for (k = 1; ha1[i1 - k] == ha2[i2 - k]; k++) if (k == xenv->snake_cnt) { best = v; spl->i1 = i1; spl->i2 = i2; break; } } } if (best > 0) { spl->min_lo = 1; spl->min_hi = 0; return ec; } for (best = 0, d = bmax; d >= bmin; d -= 2) { dd = d > bmid ? d - bmid: bmid - d; i1 = kvdb[d]; i2 = i1 - d; v = (lim1 - i1) + (lim2 - i2) - dd; if (v > XDL_K_HEUR * ec && v > best && off1 < i1 && i1 <= lim1 - xenv->snake_cnt && off2 < i2 && i2 <= lim2 - xenv->snake_cnt) { for (k = 0; ha1[i1 + k] == ha2[i2 + k]; k++) if (k == xenv->snake_cnt - 1) { best = v; spl->i1 = i1; spl->i2 = i2; break; } } } if (best > 0) { spl->min_lo = 0; spl->min_hi = 1; return ec; } } /* * Enough is enough. We spent too much time here and now we * collect the furthest reaching path using the (i1 + i2) * measure. */ if (ec >= xenv->mxcost) { long fbest, fbest1, bbest, bbest1; fbest = fbest1 = -1; for (d = fmax; d >= fmin; d -= 2) { i1 = XDL_MIN(kvdf[d], lim1); i2 = i1 - d; if (lim2 < i2) i1 = lim2 + d, i2 = lim2; if (fbest < i1 + i2) { fbest = i1 + i2; fbest1 = i1; } } bbest = bbest1 = XDL_LINE_MAX; for (d = bmax; d >= bmin; d -= 2) { i1 = XDL_MAX(off1, kvdb[d]); i2 = i1 - d; if (i2 < off2) i1 = off2 + d, i2 = off2; if (i1 + i2 < bbest) { bbest = i1 + i2; bbest1 = i1; } } if ((lim1 + lim2) - bbest < fbest - (off1 + off2)) { spl->i1 = fbest1; spl->i2 = fbest - fbest1; spl->min_lo = 1; spl->min_hi = 0; } else { spl->i1 = bbest1; spl->i2 = bbest - bbest1; spl->min_lo = 0; spl->min_hi = 1; } return ec; } } } /* * Rule: "Divide et Impera" (divide & conquer). Recursively split the box in * sub-boxes by calling the box splitting function. Note that the real job * (marking changed lines) is done in the two boundary reaching checks. */ int xdl_recs_cmp(diffdata_t *dd1, long off1, long lim1, diffdata_t *dd2, long off2, long lim2, long *kvdf, long *kvdb, int need_min, xdalgoenv_t *xenv) { unsigned long const *ha1 = dd1->ha, *ha2 = dd2->ha; /* * Shrink the box by walking through each diagonal snake (SW and NE). */ for (; off1 < lim1 && off2 < lim2 && ha1[off1] == ha2[off2]; off1++, off2++); for (; off1 < lim1 && off2 < lim2 && ha1[lim1 - 1] == ha2[lim2 - 1]; lim1--, lim2--); /* * If one dimension is empty, then all records on the other one must * be obviously changed. */ if (off1 == lim1) { char *rchg2 = dd2->rchg; long *rindex2 = dd2->rindex; for (; off2 < lim2; off2++) rchg2[rindex2[off2]] = 1; } else if (off2 == lim2) { char *rchg1 = dd1->rchg; long *rindex1 = dd1->rindex; for (; off1 < lim1; off1++) rchg1[rindex1[off1]] = 1; } else { xdpsplit_t spl; spl.i1 = spl.i2 = 0; /* * Divide ... */ if (xdl_split(ha1, off1, lim1, ha2, off2, lim2, kvdf, kvdb, need_min, &spl, xenv) < 0) { return -1; } /* * ... et Impera. */ if (xdl_recs_cmp(dd1, off1, spl.i1, dd2, off2, spl.i2, kvdf, kvdb, spl.min_lo, xenv) < 0 || xdl_recs_cmp(dd1, spl.i1, lim1, dd2, spl.i2, lim2, kvdf, kvdb, spl.min_hi, xenv) < 0) { return -1; } } return 0; } int xdl_do_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdfenv_t *xe) { long ndiags; long *kvd, *kvdf, *kvdb; xdalgoenv_t xenv; diffdata_t dd1, dd2; if (XDF_DIFF_ALG(xpp->flags) == XDF_PATIENCE_DIFF) return xdl_do_patience_diff(mf1, mf2, xpp, xe); if (XDF_DIFF_ALG(xpp->flags) == XDF_HISTOGRAM_DIFF) return xdl_do_histogram_diff(mf1, mf2, xpp, xe); if (xdl_prepare_env(mf1, mf2, xpp, xe) < 0) { return -1; } /* * Allocate and setup K vectors to be used by the differential * algorithm. * * One is to store the forward path and one to store the backward path. */ ndiags = xe->xdf1.nreff + xe->xdf2.nreff + 3; if (!(kvd = (long *) xdl_malloc((2 * ndiags + 2) * sizeof(long)))) { xdl_free_env(xe); return -1; } kvdf = kvd; kvdb = kvdf + ndiags; kvdf += xe->xdf2.nreff + 1; kvdb += xe->xdf2.nreff + 1; xenv.mxcost = xdl_bogosqrt(ndiags); if (xenv.mxcost < XDL_MAX_COST_MIN) xenv.mxcost = XDL_MAX_COST_MIN; xenv.snake_cnt = XDL_SNAKE_CNT; xenv.heur_min = XDL_HEUR_MIN_COST; dd1.nrec = xe->xdf1.nreff; dd1.ha = xe->xdf1.ha; dd1.rchg = xe->xdf1.rchg; dd1.rindex = xe->xdf1.rindex; dd2.nrec = xe->xdf2.nreff; dd2.ha = xe->xdf2.ha; dd2.rchg = xe->xdf2.rchg; dd2.rindex = xe->xdf2.rindex; if (xdl_recs_cmp(&dd1, 0, dd1.nrec, &dd2, 0, dd2.nrec, kvdf, kvdb, (xpp->flags & XDF_NEED_MINIMAL) != 0, &xenv) < 0) { xdl_free(kvd); xdl_free_env(xe); return -1; } xdl_free(kvd); return 0; } static xdchange_t *xdl_add_change(xdchange_t *xscr, long i1, long i2, long chg1, long chg2) { xdchange_t *xch; if (!(xch = (xdchange_t *) xdl_malloc(sizeof(xdchange_t)))) return NULL; xch->next = xscr; xch->i1 = i1; xch->i2 = i2; xch->chg1 = chg1; xch->chg2 = chg2; xch->ignore = 0; return xch; } static int recs_match(xrecord_t *rec1, xrecord_t *rec2, long flags) { return (rec1->ha == rec2->ha && xdl_recmatch(rec1->ptr, rec1->size, rec2->ptr, rec2->size, flags)); } /* * If a line is indented more than this, get_indent() just returns this value. * This avoids having to do absurd amounts of work for data that are not * human-readable text, and also ensures that the output of get_indent fits * within an int. */ #define MAX_INDENT 200 /* * Return the amount of indentation of the specified line, treating TAB as 8 * columns. Return -1 if line is empty or contains only whitespace. Clamp the * output value at MAX_INDENT. */ static int get_indent(xrecord_t *rec) { long i; int ret = 0; for (i = 0; i < rec->size; i++) { char c = rec->ptr[i]; if (!XDL_ISSPACE(c)) return ret; else if (c == ' ') ret += 1; else if (c == '\t') ret += 8 - ret % 8; /* ignore other whitespace characters */ if (ret >= MAX_INDENT) return MAX_INDENT; } /* The line contains only whitespace. */ return -1; } /* * If more than this number of consecutive blank rows are found, just return * this value. This avoids requiring O(N^2) work for pathological cases, and * also ensures that the output of score_split fits in an int. */ #define MAX_BLANKS 20 /* Characteristics measured about a hypothetical split position. */ struct split_measurement { /* * Is the split at the end of the file (aside from any blank lines)? */ int end_of_file; /* * How much is the line immediately following the split indented (or -1 * if the line is blank): */ int indent; /* * How many consecutive lines above the split are blank? */ int pre_blank; /* * How much is the nearest non-blank line above the split indented (or * -1 if there is no such line)? */ int pre_indent; /* * How many lines after the line following the split are blank? */ int post_blank; /* * How much is the nearest non-blank line after the line following the * split indented (or -1 if there is no such line)? */ int post_indent; }; struct split_score { /* The effective indent of this split (smaller is preferred). */ int effective_indent; /* Penalty for this split (smaller is preferred). */ int penalty; }; /* * Fill m with information about a hypothetical split of xdf above line split. */ static void measure_split(const xdfile_t *xdf, long split, struct split_measurement *m) { long i; if (split >= xdf->nrec) { m->end_of_file = 1; m->indent = -1; } else { m->end_of_file = 0; m->indent = get_indent(xdf->recs[split]); } m->pre_blank = 0; m->pre_indent = -1; for (i = split - 1; i >= 0; i--) { m->pre_indent = get_indent(xdf->recs[i]); if (m->pre_indent != -1) break; m->pre_blank += 1; if (m->pre_blank == MAX_BLANKS) { m->pre_indent = 0; break; } } m->post_blank = 0; m->post_indent = -1; for (i = split + 1; i < xdf->nrec; i++) { m->post_indent = get_indent(xdf->recs[i]); if (m->post_indent != -1) break; m->post_blank += 1; if (m->post_blank == MAX_BLANKS) { m->post_indent = 0; break; } } } /* * The empirically-determined weight factors used by score_split() below. * Larger values means that the position is a less favorable place to split. * * Note that scores are only ever compared against each other, so multiplying * all of these weight/penalty values by the same factor wouldn't change the * heuristic's behavior. Still, we need to set that arbitrary scale *somehow*. * In practice, these numbers are chosen to be large enough that they can be * adjusted relative to each other with sufficient precision despite using * integer math. */ /* Penalty if there are no non-blank lines before the split */ #define START_OF_FILE_PENALTY 1 /* Penalty if there are no non-blank lines after the split */ #define END_OF_FILE_PENALTY 21 /* Multiplier for the number of blank lines around the split */ #define TOTAL_BLANK_WEIGHT (-30) /* Multiplier for the number of blank lines after the split */ #define POST_BLANK_WEIGHT 6 /* * Penalties applied if the line is indented more than its predecessor */ #define RELATIVE_INDENT_PENALTY (-4) #define RELATIVE_INDENT_WITH_BLANK_PENALTY 10 /* * Penalties applied if the line is indented less than both its predecessor and * its successor */ #define RELATIVE_OUTDENT_PENALTY 24 #define RELATIVE_OUTDENT_WITH_BLANK_PENALTY 17 /* * Penalties applied if the line is indented less than its predecessor but not * less than its successor */ #define RELATIVE_DEDENT_PENALTY 23 #define RELATIVE_DEDENT_WITH_BLANK_PENALTY 17 /* * We only consider whether the sum of the effective indents for splits are * less than (-1), equal to (0), or greater than (+1) each other. The resulting * value is multiplied by the following weight and combined with the penalty to * determine the better of two scores. */ #define INDENT_WEIGHT 60 /* * How far do we slide a hunk at most? */ #define INDENT_HEURISTIC_MAX_SLIDING 100 /* * Compute a badness score for the hypothetical split whose measurements are * stored in m. The weight factors were determined empirically using the tools * and corpus described in * * https://github.com/mhagger/diff-slider-tools * * Also see that project if you want to improve the weights based on, for * example, a larger or more diverse corpus. */ static void score_add_split(const struct split_measurement *m, struct split_score *s) { /* * A place to accumulate penalty factors (positive makes this index more * favored): */ int post_blank, total_blank, indent, any_blanks; if (m->pre_indent == -1 && m->pre_blank == 0) s->penalty += START_OF_FILE_PENALTY; if (m->end_of_file) s->penalty += END_OF_FILE_PENALTY; /* * Set post_blank to the number of blank lines following the split, * including the line immediately after the split: */ post_blank = (m->indent == -1) ? 1 + m->post_blank : 0; total_blank = m->pre_blank + post_blank; /* Penalties based on nearby blank lines: */ s->penalty += TOTAL_BLANK_WEIGHT * total_blank; s->penalty += POST_BLANK_WEIGHT * post_blank; if (m->indent != -1) indent = m->indent; else indent = m->post_indent; any_blanks = (total_blank != 0); /* Note that the effective indent is -1 at the end of the file: */ s->effective_indent += indent; if (indent == -1) { /* No additional adjustments needed. */ } else if (m->pre_indent == -1) { /* No additional adjustments needed. */ } else if (indent > m->pre_indent) { /* * The line is indented more than its predecessor. */ s->penalty += any_blanks ? RELATIVE_INDENT_WITH_BLANK_PENALTY : RELATIVE_INDENT_PENALTY; } else if (indent == m->pre_indent) { /* * The line has the same indentation level as its predecessor. * No additional adjustments needed. */ } else { /* * The line is indented less than its predecessor. It could be * the block terminator of the previous block, but it could * also be the start of a new block (e.g., an "else" block, or * maybe the previous block didn't have a block terminator). * Try to distinguish those cases based on what comes next: */ if (m->post_indent != -1 && m->post_indent > indent) { /* * The following line is indented more. So it is likely * that this line is the start of a block. */ s->penalty += any_blanks ? RELATIVE_OUTDENT_WITH_BLANK_PENALTY : RELATIVE_OUTDENT_PENALTY; } else { /* * That was probably the end of a block. */ s->penalty += any_blanks ? RELATIVE_DEDENT_WITH_BLANK_PENALTY : RELATIVE_DEDENT_PENALTY; } } } static int score_cmp(struct split_score *s1, struct split_score *s2) { /* -1 if s1.effective_indent < s2->effective_indent, etc. */ int cmp_indents = ((s1->effective_indent > s2->effective_indent) - (s1->effective_indent < s2->effective_indent)); return INDENT_WEIGHT * cmp_indents + (s1->penalty - s2->penalty); } /* * Represent a group of changed lines in an xdfile_t (i.e., a contiguous group * of lines that was inserted or deleted from the corresponding version of the * file). We consider there to be such a group at the beginning of the file, at * the end of the file, and between any two unchanged lines, though most such * groups will usually be empty. * * If the first line in a group is equal to the line following the group, then * the group can be slid down. Similarly, if the last line in a group is equal * to the line preceding the group, then the group can be slid up. See * group_slide_down() and group_slide_up(). * * Note that loops that are testing for changed lines in xdf->rchg do not need * index bounding since the array is prepared with a zero at position -1 and N. */ struct xdlgroup { /* * The index of the first changed line in the group, or the index of * the unchanged line above which the (empty) group is located. */ long start; /* * The index of the first unchanged line after the group. For an empty * group, end is equal to start. */ long end; }; /* * Initialize g to point at the first group in xdf. */ static void group_init(xdfile_t *xdf, struct xdlgroup *g) { g->start = g->end = 0; while (xdf->rchg[g->end]) g->end++; } /* * Move g to describe the next (possibly empty) group in xdf and return 0. If g * is already at the end of the file, do nothing and return -1. */ static inline int group_next(xdfile_t *xdf, struct xdlgroup *g) { if (g->end == xdf->nrec) return -1; g->start = g->end + 1; for (g->end = g->start; xdf->rchg[g->end]; g->end++) ; return 0; } /* * Move g to describe the previous (possibly empty) group in xdf and return 0. * If g is already at the beginning of the file, do nothing and return -1. */ static inline int group_previous(xdfile_t *xdf, struct xdlgroup *g) { if (g->start == 0) return -1; g->end = g->start - 1; for (g->start = g->end; xdf->rchg[g->start - 1]; g->start--) ; return 0; } /* * If g can be slid toward the end of the file, do so, and if it bumps into a * following group, expand this group to include it. Return 0 on success or -1 * if g cannot be slid down. */ static int group_slide_down(xdfile_t *xdf, struct xdlgroup *g, long flags) { if (g->end < xdf->nrec && recs_match(xdf->recs[g->start], xdf->recs[g->end], flags)) { xdf->rchg[g->start++] = 0; xdf->rchg[g->end++] = 1; while (xdf->rchg[g->end]) g->end++; return 0; } else { return -1; } } /* * If g can be slid toward the beginning of the file, do so, and if it bumps * into a previous group, expand this group to include it. Return 0 on success * or -1 if g cannot be slid up. */ static int group_slide_up(xdfile_t *xdf, struct xdlgroup *g, long flags) { if (g->start > 0 && recs_match(xdf->recs[g->start - 1], xdf->recs[g->end - 1], flags)) { xdf->rchg[--g->start] = 1; xdf->rchg[--g->end] = 0; while (xdf->rchg[g->start - 1]) g->start--; return 0; } else { return -1; } } static void xdl_bug(const char *msg) { fprintf(stderr, "BUG: %s\n", msg); exit(1); } /* * Move back and forward change groups for a consistent and pretty diff output. * This also helps in finding joinable change groups and reducing the diff * size. */ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) { struct xdlgroup g, go; long earliest_end, end_matching_other; long groupsize; group_init(xdf, &g); group_init(xdfo, &go); while (1) { /* * If the group is empty in the to-be-compacted file, skip it: */ if (g.end == g.start) goto next; /* * Now shift the change up and then down as far as possible in * each direction. If it bumps into any other changes, merge * them. */ do { groupsize = g.end - g.start; /* * Keep track of the last "end" index that causes this * group to align with a group of changed lines in the * other file. -1 indicates that we haven't found such * a match yet: */ end_matching_other = -1; /* Shift the group backward as much as possible: */ while (!group_slide_up(xdf, &g, flags)) if (group_previous(xdfo, &go)) xdl_bug("group sync broken sliding up"); /* * This is this highest that this group can be shifted. * Record its end index: */ earliest_end = g.end; if (go.end > go.start) end_matching_other = g.end; /* Now shift the group forward as far as possible: */ while (1) { if (group_slide_down(xdf, &g, flags)) break; if (group_next(xdfo, &go)) xdl_bug("group sync broken sliding down"); if (go.end > go.start) end_matching_other = g.end; } } while (groupsize != g.end - g.start); /* * If the group can be shifted, then we can possibly use this * freedom to produce a more intuitive diff. * * The group is currently shifted as far down as possible, so * the heuristics below only have to handle upwards shifts. */ if (g.end == earliest_end) { /* no shifting was possible */ } else if (end_matching_other != -1) { /* * Move the possibly merged group of changes back to * line up with the last group of changes from the * other file that it can align with. */ while (go.end == go.start) { if (group_slide_up(xdf, &g, flags)) xdl_bug("match disappeared"); if (group_previous(xdfo, &go)) xdl_bug("group sync broken sliding to match"); } } else if (flags & XDF_INDENT_HEURISTIC) { /* * Indent heuristic: a group of pure add/delete lines * implies two splits, one between the end of the * "before" context and the start of the group, and * another between the end of the group and the * beginning of the "after" context. Some splits are * aesthetically better and some are worse. We compute * a badness "score" for each split, and add the scores * for the two splits to define a "score" for each * position that the group can be shifted to. Then we * pick the shift with the lowest score. */ long shift, best_shift = -1; struct split_score best_score; shift = earliest_end; if (g.end - groupsize - 1 > shift) shift = g.end - groupsize - 1; if (g.end - INDENT_HEURISTIC_MAX_SLIDING > shift) shift = g.end - INDENT_HEURISTIC_MAX_SLIDING; for (; shift <= g.end; shift++) { struct split_measurement m; struct split_score score = {0, 0}; measure_split(xdf, shift, &m); score_add_split(&m, &score); measure_split(xdf, shift - groupsize, &m); score_add_split(&m, &score); if (best_shift == -1 || score_cmp(&score, &best_score) <= 0) { best_score.effective_indent = score.effective_indent; best_score.penalty = score.penalty; best_shift = shift; } } while (g.end > best_shift) { if (group_slide_up(xdf, &g, flags)) xdl_bug("best shift unreached"); if (group_previous(xdfo, &go)) xdl_bug("group sync broken sliding to blank line"); } } next: /* Move past the just-processed group: */ if (group_next(xdf, &g)) break; if (group_next(xdfo, &go)) xdl_bug("group sync broken moving to next group"); } if (!group_next(xdfo, &go)) xdl_bug("group sync broken at end of file"); return 0; } int xdl_build_script(xdfenv_t *xe, xdchange_t **xscr) { xdchange_t *cscr = NULL, *xch; char *rchg1 = xe->xdf1.rchg, *rchg2 = xe->xdf2.rchg; long i1, i2, l1, l2; /* * Trivial. Collects "groups" of changes and creates an edit script. */ for (i1 = xe->xdf1.nrec, i2 = xe->xdf2.nrec; i1 >= 0 || i2 >= 0; i1--, i2--) if (rchg1[i1 - 1] || rchg2[i2 - 1]) { for (l1 = i1; rchg1[i1 - 1]; i1--); for (l2 = i2; rchg2[i2 - 1]; i2--); if (!(xch = xdl_add_change(cscr, i1, i2, l1 - i1, l2 - i2))) { xdl_free_script(cscr); return -1; } cscr = xch; } *xscr = cscr; return 0; } void xdl_free_script(xdchange_t *xscr) { xdchange_t *xch; while ((xch = xscr) != NULL) { xscr = xscr->next; xdl_free(xch); } } static int xdl_call_hunk_func(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb, xdemitconf_t const *xecfg) { xdchange_t *xch, *xche; for (xch = xscr; xch; xch = xche->next) { xche = xdl_get_hunk(&xch, xecfg); if (!xch) break; if (xecfg->hunk_func(xch->i1, xche->i1 + xche->chg1 - xch->i1, xch->i2, xche->i2 + xche->chg2 - xch->i2, ecb->priv) < 0) return -1; } return 0; } static void xdl_mark_ignorable(xdchange_t *xscr, xdfenv_t *xe, long flags) { xdchange_t *xch; for (xch = xscr; xch; xch = xch->next) { int ignore = 1; xrecord_t **rec; long i; rec = &xe->xdf1.recs[xch->i1]; for (i = 0; i < xch->chg1 && ignore; i++) ignore = xdl_blankline(rec[i]->ptr, rec[i]->size, flags); rec = &xe->xdf2.recs[xch->i2]; for (i = 0; i < xch->chg2 && ignore; i++) ignore = xdl_blankline(rec[i]->ptr, rec[i]->size, flags); xch->ignore = ignore; } } int xdl_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *ecb) { xdchange_t *xscr; xdfenv_t xe; emit_func_t ef = xecfg->hunk_func ? xdl_call_hunk_func : xdl_emit_diff; if (xdl_do_diff(mf1, mf2, xpp, &xe) < 0) { return -1; } if (xdl_change_compact(&xe.xdf1, &xe.xdf2, xpp->flags) < 0 || xdl_change_compact(&xe.xdf2, &xe.xdf1, xpp->flags) < 0 || xdl_build_script(&xe, &xscr) < 0) { xdl_free_env(&xe); return -1; } if (xscr) { if (xpp->flags & XDF_IGNORE_BLANK_LINES) xdl_mark_ignorable(xscr, &xe, xpp->flags); if (ef(&xe, xscr, ecb, xecfg) < 0) { xdl_free_script(xscr); xdl_free_env(&xe); return -1; } xdl_free_script(xscr); } xdl_free_env(&xe); return 0; }