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http-push.c::finish_request(): request is initialized by the for loop index-pack.c::free_base_data(): b is initialized by the for loop merge-recursive.c::process_renames(): move compare to narrower scope, and remove unused assignments to it remove unused variable renames2 xdiff/xdiffi.c::xdl_recs_cmp(): remove unused variable ec xdiff/xemit.c::xdl_emit_diff(): xche is always overwritten Signed-off-by: Benjamin Kramer <benny.kra@googlemail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
570 lines
15 KiB
C
570 lines
15 KiB
C
/*
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* LibXDiff by Davide Libenzi ( File Differential Library )
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* Copyright (C) 2003 Davide Libenzi
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Davide Libenzi <davidel@xmailserver.org>
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*
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*/
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#include "xinclude.h"
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#define XDL_MAX_COST_MIN 256
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#define XDL_HEUR_MIN_COST 256
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#define XDL_LINE_MAX (long)((1UL << (8 * sizeof(long) - 1)) - 1)
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#define XDL_SNAKE_CNT 20
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#define XDL_K_HEUR 4
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typedef struct s_xdpsplit {
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long i1, i2;
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int min_lo, min_hi;
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} xdpsplit_t;
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static long xdl_split(unsigned long const *ha1, long off1, long lim1,
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unsigned long const *ha2, long off2, long lim2,
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long *kvdf, long *kvdb, int need_min, xdpsplit_t *spl,
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xdalgoenv_t *xenv);
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static xdchange_t *xdl_add_change(xdchange_t *xscr, long i1, long i2, long chg1, long chg2);
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/*
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* See "An O(ND) Difference Algorithm and its Variations", by Eugene Myers.
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* Basically considers a "box" (off1, off2, lim1, lim2) and scan from both
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* the forward diagonal starting from (off1, off2) and the backward diagonal
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* starting from (lim1, lim2). If the K values on the same diagonal crosses
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* returns the furthest point of reach. We might end up having to expensive
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* cases using this algorithm is full, so a little bit of heuristic is needed
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* to cut the search and to return a suboptimal point.
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*/
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static long xdl_split(unsigned long const *ha1, long off1, long lim1,
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unsigned long const *ha2, long off2, long lim2,
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long *kvdf, long *kvdb, int need_min, xdpsplit_t *spl,
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xdalgoenv_t *xenv) {
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long dmin = off1 - lim2, dmax = lim1 - off2;
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long fmid = off1 - off2, bmid = lim1 - lim2;
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long odd = (fmid - bmid) & 1;
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long fmin = fmid, fmax = fmid;
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long bmin = bmid, bmax = bmid;
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long ec, d, i1, i2, prev1, best, dd, v, k;
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/*
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* Set initial diagonal values for both forward and backward path.
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*/
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kvdf[fmid] = off1;
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kvdb[bmid] = lim1;
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for (ec = 1;; ec++) {
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int got_snake = 0;
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/*
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* We need to extent the diagonal "domain" by one. If the next
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* values exits the box boundaries we need to change it in the
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* opposite direction because (max - min) must be a power of two.
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* Also we initialize the external K value to -1 so that we can
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* avoid extra conditions check inside the core loop.
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*/
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if (fmin > dmin)
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kvdf[--fmin - 1] = -1;
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else
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++fmin;
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if (fmax < dmax)
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kvdf[++fmax + 1] = -1;
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else
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--fmax;
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for (d = fmax; d >= fmin; d -= 2) {
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if (kvdf[d - 1] >= kvdf[d + 1])
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i1 = kvdf[d - 1] + 1;
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else
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i1 = kvdf[d + 1];
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prev1 = i1;
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i2 = i1 - d;
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for (; i1 < lim1 && i2 < lim2 && ha1[i1] == ha2[i2]; i1++, i2++);
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if (i1 - prev1 > xenv->snake_cnt)
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got_snake = 1;
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kvdf[d] = i1;
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if (odd && bmin <= d && d <= bmax && kvdb[d] <= i1) {
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spl->i1 = i1;
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spl->i2 = i2;
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spl->min_lo = spl->min_hi = 1;
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return ec;
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}
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}
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/*
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* We need to extent the diagonal "domain" by one. If the next
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* values exits the box boundaries we need to change it in the
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* opposite direction because (max - min) must be a power of two.
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* Also we initialize the external K value to -1 so that we can
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* avoid extra conditions check inside the core loop.
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*/
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if (bmin > dmin)
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kvdb[--bmin - 1] = XDL_LINE_MAX;
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else
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++bmin;
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if (bmax < dmax)
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kvdb[++bmax + 1] = XDL_LINE_MAX;
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else
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--bmax;
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for (d = bmax; d >= bmin; d -= 2) {
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if (kvdb[d - 1] < kvdb[d + 1])
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i1 = kvdb[d - 1];
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else
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i1 = kvdb[d + 1] - 1;
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prev1 = i1;
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i2 = i1 - d;
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for (; i1 > off1 && i2 > off2 && ha1[i1 - 1] == ha2[i2 - 1]; i1--, i2--);
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if (prev1 - i1 > xenv->snake_cnt)
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got_snake = 1;
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kvdb[d] = i1;
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if (!odd && fmin <= d && d <= fmax && i1 <= kvdf[d]) {
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spl->i1 = i1;
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spl->i2 = i2;
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spl->min_lo = spl->min_hi = 1;
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return ec;
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}
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}
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if (need_min)
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continue;
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/*
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* If the edit cost is above the heuristic trigger and if
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* we got a good snake, we sample current diagonals to see
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* if some of the, have reached an "interesting" path. Our
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* measure is a function of the distance from the diagonal
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* corner (i1 + i2) penalized with the distance from the
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* mid diagonal itself. If this value is above the current
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* edit cost times a magic factor (XDL_K_HEUR) we consider
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* it interesting.
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*/
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if (got_snake && ec > xenv->heur_min) {
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for (best = 0, d = fmax; d >= fmin; d -= 2) {
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dd = d > fmid ? d - fmid: fmid - d;
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i1 = kvdf[d];
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i2 = i1 - d;
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v = (i1 - off1) + (i2 - off2) - dd;
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if (v > XDL_K_HEUR * ec && v > best &&
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off1 + xenv->snake_cnt <= i1 && i1 < lim1 &&
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off2 + xenv->snake_cnt <= i2 && i2 < lim2) {
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for (k = 1; ha1[i1 - k] == ha2[i2 - k]; k++)
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if (k == xenv->snake_cnt) {
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best = v;
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spl->i1 = i1;
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spl->i2 = i2;
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break;
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}
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}
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}
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if (best > 0) {
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spl->min_lo = 1;
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spl->min_hi = 0;
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return ec;
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}
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for (best = 0, d = bmax; d >= bmin; d -= 2) {
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dd = d > bmid ? d - bmid: bmid - d;
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i1 = kvdb[d];
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i2 = i1 - d;
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v = (lim1 - i1) + (lim2 - i2) - dd;
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if (v > XDL_K_HEUR * ec && v > best &&
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off1 < i1 && i1 <= lim1 - xenv->snake_cnt &&
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off2 < i2 && i2 <= lim2 - xenv->snake_cnt) {
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for (k = 0; ha1[i1 + k] == ha2[i2 + k]; k++)
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if (k == xenv->snake_cnt - 1) {
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best = v;
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spl->i1 = i1;
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spl->i2 = i2;
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break;
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}
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}
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}
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if (best > 0) {
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spl->min_lo = 0;
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spl->min_hi = 1;
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return ec;
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}
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}
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/*
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* Enough is enough. We spent too much time here and now we collect
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* the furthest reaching path using the (i1 + i2) measure.
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*/
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if (ec >= xenv->mxcost) {
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long fbest, fbest1, bbest, bbest1;
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fbest = fbest1 = -1;
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for (d = fmax; d >= fmin; d -= 2) {
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i1 = XDL_MIN(kvdf[d], lim1);
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i2 = i1 - d;
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if (lim2 < i2)
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i1 = lim2 + d, i2 = lim2;
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if (fbest < i1 + i2) {
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fbest = i1 + i2;
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fbest1 = i1;
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}
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}
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bbest = bbest1 = XDL_LINE_MAX;
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for (d = bmax; d >= bmin; d -= 2) {
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i1 = XDL_MAX(off1, kvdb[d]);
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i2 = i1 - d;
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if (i2 < off2)
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i1 = off2 + d, i2 = off2;
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if (i1 + i2 < bbest) {
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bbest = i1 + i2;
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bbest1 = i1;
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}
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}
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if ((lim1 + lim2) - bbest < fbest - (off1 + off2)) {
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spl->i1 = fbest1;
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spl->i2 = fbest - fbest1;
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spl->min_lo = 1;
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spl->min_hi = 0;
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} else {
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spl->i1 = bbest1;
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spl->i2 = bbest - bbest1;
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spl->min_lo = 0;
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spl->min_hi = 1;
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}
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return ec;
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}
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}
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}
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/*
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* Rule: "Divide et Impera". Recursively split the box in sub-boxes by calling
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* the box splitting function. Note that the real job (marking changed lines)
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* is done in the two boundary reaching checks.
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*/
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int xdl_recs_cmp(diffdata_t *dd1, long off1, long lim1,
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diffdata_t *dd2, long off2, long lim2,
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long *kvdf, long *kvdb, int need_min, xdalgoenv_t *xenv) {
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unsigned long const *ha1 = dd1->ha, *ha2 = dd2->ha;
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/*
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* Shrink the box by walking through each diagonal snake (SW and NE).
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*/
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for (; off1 < lim1 && off2 < lim2 && ha1[off1] == ha2[off2]; off1++, off2++);
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for (; off1 < lim1 && off2 < lim2 && ha1[lim1 - 1] == ha2[lim2 - 1]; lim1--, lim2--);
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/*
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* If one dimension is empty, then all records on the other one must
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* be obviously changed.
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*/
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if (off1 == lim1) {
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char *rchg2 = dd2->rchg;
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long *rindex2 = dd2->rindex;
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for (; off2 < lim2; off2++)
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rchg2[rindex2[off2]] = 1;
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} else if (off2 == lim2) {
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char *rchg1 = dd1->rchg;
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long *rindex1 = dd1->rindex;
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for (; off1 < lim1; off1++)
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rchg1[rindex1[off1]] = 1;
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} else {
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xdpsplit_t spl;
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spl.i1 = spl.i2 = 0;
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/*
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* Divide ...
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*/
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if (xdl_split(ha1, off1, lim1, ha2, off2, lim2, kvdf, kvdb,
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need_min, &spl, xenv) < 0) {
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return -1;
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}
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/*
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* ... et Impera.
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*/
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if (xdl_recs_cmp(dd1, off1, spl.i1, dd2, off2, spl.i2,
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kvdf, kvdb, spl.min_lo, xenv) < 0 ||
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xdl_recs_cmp(dd1, spl.i1, lim1, dd2, spl.i2, lim2,
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kvdf, kvdb, spl.min_hi, xenv) < 0) {
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return -1;
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}
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}
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return 0;
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}
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int xdl_do_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
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xdfenv_t *xe) {
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long ndiags;
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long *kvd, *kvdf, *kvdb;
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xdalgoenv_t xenv;
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diffdata_t dd1, dd2;
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if (xpp->flags & XDF_PATIENCE_DIFF)
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return xdl_do_patience_diff(mf1, mf2, xpp, xe);
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if (xdl_prepare_env(mf1, mf2, xpp, xe) < 0) {
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return -1;
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}
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/*
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* Allocate and setup K vectors to be used by the differential algorithm.
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* One is to store the forward path and one to store the backward path.
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*/
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ndiags = xe->xdf1.nreff + xe->xdf2.nreff + 3;
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if (!(kvd = (long *) xdl_malloc((2 * ndiags + 2) * sizeof(long)))) {
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xdl_free_env(xe);
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return -1;
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}
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kvdf = kvd;
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kvdb = kvdf + ndiags;
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kvdf += xe->xdf2.nreff + 1;
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kvdb += xe->xdf2.nreff + 1;
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xenv.mxcost = xdl_bogosqrt(ndiags);
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if (xenv.mxcost < XDL_MAX_COST_MIN)
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xenv.mxcost = XDL_MAX_COST_MIN;
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xenv.snake_cnt = XDL_SNAKE_CNT;
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xenv.heur_min = XDL_HEUR_MIN_COST;
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dd1.nrec = xe->xdf1.nreff;
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dd1.ha = xe->xdf1.ha;
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dd1.rchg = xe->xdf1.rchg;
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dd1.rindex = xe->xdf1.rindex;
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dd2.nrec = xe->xdf2.nreff;
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dd2.ha = xe->xdf2.ha;
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dd2.rchg = xe->xdf2.rchg;
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dd2.rindex = xe->xdf2.rindex;
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if (xdl_recs_cmp(&dd1, 0, dd1.nrec, &dd2, 0, dd2.nrec,
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kvdf, kvdb, (xpp->flags & XDF_NEED_MINIMAL) != 0, &xenv) < 0) {
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xdl_free(kvd);
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xdl_free_env(xe);
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return -1;
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}
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xdl_free(kvd);
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return 0;
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}
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static xdchange_t *xdl_add_change(xdchange_t *xscr, long i1, long i2, long chg1, long chg2) {
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xdchange_t *xch;
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if (!(xch = (xdchange_t *) xdl_malloc(sizeof(xdchange_t))))
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return NULL;
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xch->next = xscr;
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xch->i1 = i1;
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xch->i2 = i2;
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xch->chg1 = chg1;
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xch->chg2 = chg2;
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return xch;
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}
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int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
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long ix, ixo, ixs, ixref, grpsiz, nrec = xdf->nrec;
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char *rchg = xdf->rchg, *rchgo = xdfo->rchg;
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xrecord_t **recs = xdf->recs;
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/*
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* This is the same of what GNU diff does. Move back and forward
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* change groups for a consistent and pretty diff output. This also
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* helps in finding joinable change groups and reduce the diff size.
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*/
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for (ix = ixo = 0;;) {
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/*
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* Find the first changed line in the to-be-compacted file.
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* We need to keep track of both indexes, so if we find a
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* changed lines group on the other file, while scanning the
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* to-be-compacted file, we need to skip it properly. Note
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* that loops that are testing for changed lines on rchg* do
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* not need index bounding since the array is prepared with
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* a zero at position -1 and N.
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*/
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for (; ix < nrec && !rchg[ix]; ix++)
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while (rchgo[ixo++]);
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if (ix == nrec)
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break;
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/*
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* Record the start of a changed-group in the to-be-compacted file
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* and find the end of it, on both to-be-compacted and other file
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* indexes (ix and ixo).
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*/
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ixs = ix;
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for (ix++; rchg[ix]; ix++);
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for (; rchgo[ixo]; ixo++);
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do {
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grpsiz = ix - ixs;
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/*
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* If the line before the current change group, is equal to
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* the last line of the current change group, shift backward
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* the group.
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*/
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while (ixs > 0 && recs[ixs - 1]->ha == recs[ix - 1]->ha &&
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xdl_recmatch(recs[ixs - 1]->ptr, recs[ixs - 1]->size, recs[ix - 1]->ptr, recs[ix - 1]->size, flags)) {
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rchg[--ixs] = 1;
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rchg[--ix] = 0;
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/*
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* This change might have joined two change groups,
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* so we try to take this scenario in account by moving
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* the start index accordingly (and so the other-file
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* end-of-group index).
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*/
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for (; rchg[ixs - 1]; ixs--);
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while (rchgo[--ixo]);
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}
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/*
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* Record the end-of-group position in case we are matched
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* with a group of changes in the other file (that is, the
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* change record before the enf-of-group index in the other
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* file is set).
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*/
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ixref = rchgo[ixo - 1] ? ix: nrec;
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/*
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* If the first line of the current change group, is equal to
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* the line next of the current change group, shift forward
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* the group.
|
|
*/
|
|
while (ix < nrec && recs[ixs]->ha == recs[ix]->ha &&
|
|
xdl_recmatch(recs[ixs]->ptr, recs[ixs]->size, recs[ix]->ptr, recs[ix]->size, flags)) {
|
|
rchg[ixs++] = 0;
|
|
rchg[ix++] = 1;
|
|
|
|
/*
|
|
* This change might have joined two change groups,
|
|
* so we try to take this scenario in account by moving
|
|
* the start index accordingly (and so the other-file
|
|
* end-of-group index). Keep tracking the reference
|
|
* index in case we are shifting together with a
|
|
* corresponding group of changes in the other file.
|
|
*/
|
|
for (; rchg[ix]; ix++);
|
|
while (rchgo[++ixo])
|
|
ixref = ix;
|
|
}
|
|
} while (grpsiz != ix - ixs);
|
|
|
|
/*
|
|
* Try to move back the possibly merged group of changes, to match
|
|
* the recorded postion in the other file.
|
|
*/
|
|
while (ixref < ix) {
|
|
rchg[--ixs] = 1;
|
|
rchg[--ix] = 0;
|
|
while (rchgo[--ixo]);
|
|
}
|
|
}
|
|
|
|
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);
|
|
}
|
|
}
|
|
|
|
|
|
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->emit_func ?
|
|
(emit_func_t)xecfg->emit_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 (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;
|
|
}
|