+++ /dev/null
-/*
- * 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
- * <http://www.gnu.org/licenses/>.
- *
- * Davide Libenzi <davidel@xmailserver.org>
- *
- */
-
-#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)
-{
- return (rec1->ha == rec2->ha);
-}
-
-/*
- * 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)
-{
- if (g->end < xdf->nrec &&
- recs_match(xdf->recs[g->start], xdf->recs[g->end])) {
- 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)
-{
- if (g->start > 0 &&
- recs_match(xdf->recs[g->start - 1], xdf->recs[g->end - 1])) {
- xdf->rchg[--g->start] = 1;
- xdf->rchg[--g->end] = 0;
-
- while (xdf->rchg[g->start - 1])
- g->start--;
-
- return 0;
- } else {
- return -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))
- 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))
- 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))
- 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))
- 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_lines(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;
- }
-}
-
-static int record_matches_regex(xrecord_t *rec, xpparam_t const *xpp) {
- xdl_regmatch_t regmatch;
- int i;
-
- for (i = 0; i < xpp->ignore_regex_nr; i++)
- if (!xdl_regexec_buf(xpp->ignore_regex[i], rec->ptr, rec->size, 1,
- ®match, 0))
- return 1;
-
- return 0;
-}
-
-static void xdl_mark_ignorable_regex(xdchange_t *xscr, const xdfenv_t *xe,
- xpparam_t const *xpp)
-{
- xdchange_t *xch;
-
- for (xch = xscr; xch; xch = xch->next) {
- xrecord_t **rec;
- int ignore = 1;
- long i;
-
- /*
- * Do not override --ignore-blank-lines.
- */
- if (xch->ignore)
- continue;
-
- rec = &xe->xdf1.recs[xch->i1];
- for (i = 0; i < xch->chg1 && ignore; i++)
- ignore = record_matches_regex(rec[i], xpp);
-
- rec = &xe->xdf2.recs[xch->i2];
- for (i = 0; i < xch->chg2 && ignore; i++)
- ignore = record_matches_regex(rec[i], xpp);
-
- 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_lines(xscr, &xe, xpp->flags);
-
- if (xpp->ignore_regex)
- xdl_mark_ignorable_regex(xscr, &xe, xpp);
-
- 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;
-}
projects / libgit2.git / blobdiff