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![Dylan Reid](/assets/img/avatar_default.png)
In xdl_recmatch, do the memcmp to check if the two lines are equal before checking if whitespace flags are set. If the lines are identical, then there is no need to check if they differ only in whitespace. This makes the common case (there is no whitespace difference) faster. It costs the case where lines are the same length and contain whitespace differences, but the common case is more than 20% faster. Signed-off-by: Dylan Reid <dgreid@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
405 lines
8.1 KiB
C
405 lines
8.1 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_GUESS_NLINES 256
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long xdl_bogosqrt(long n) {
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long i;
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/*
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* Classical integer square root approximation using shifts.
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*/
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for (i = 1; n > 0; n >>= 2)
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i <<= 1;
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return i;
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}
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int xdl_emit_diffrec(char const *rec, long size, char const *pre, long psize,
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xdemitcb_t *ecb) {
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int i = 2;
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mmbuffer_t mb[3];
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mb[0].ptr = (char *) pre;
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mb[0].size = psize;
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mb[1].ptr = (char *) rec;
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mb[1].size = size;
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if (size > 0 && rec[size - 1] != '\n') {
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mb[2].ptr = (char *) "\n\\ No newline at end of file\n";
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mb[2].size = strlen(mb[2].ptr);
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i++;
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}
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if (ecb->outf(ecb->priv, mb, i) < 0) {
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return -1;
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}
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return 0;
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}
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void *xdl_mmfile_first(mmfile_t *mmf, long *size)
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{
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*size = mmf->size;
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return mmf->ptr;
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}
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void *xdl_mmfile_next(mmfile_t *mmf, long *size)
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{
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return NULL;
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}
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long xdl_mmfile_size(mmfile_t *mmf)
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{
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return mmf->size;
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}
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int xdl_cha_init(chastore_t *cha, long isize, long icount) {
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cha->head = cha->tail = NULL;
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cha->isize = isize;
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cha->nsize = icount * isize;
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cha->ancur = cha->sncur = NULL;
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cha->scurr = 0;
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return 0;
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}
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void xdl_cha_free(chastore_t *cha) {
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chanode_t *cur, *tmp;
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for (cur = cha->head; (tmp = cur) != NULL;) {
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cur = cur->next;
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xdl_free(tmp);
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}
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}
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void *xdl_cha_alloc(chastore_t *cha) {
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chanode_t *ancur;
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void *data;
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if (!(ancur = cha->ancur) || ancur->icurr == cha->nsize) {
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if (!(ancur = (chanode_t *) xdl_malloc(sizeof(chanode_t) + cha->nsize))) {
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return NULL;
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}
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ancur->icurr = 0;
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ancur->next = NULL;
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if (cha->tail)
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cha->tail->next = ancur;
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if (!cha->head)
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cha->head = ancur;
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cha->tail = ancur;
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cha->ancur = ancur;
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}
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data = (char *) ancur + sizeof(chanode_t) + ancur->icurr;
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ancur->icurr += cha->isize;
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return data;
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}
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void *xdl_cha_first(chastore_t *cha) {
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chanode_t *sncur;
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if (!(cha->sncur = sncur = cha->head))
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return NULL;
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cha->scurr = 0;
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return (char *) sncur + sizeof(chanode_t) + cha->scurr;
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}
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void *xdl_cha_next(chastore_t *cha) {
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chanode_t *sncur;
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if (!(sncur = cha->sncur))
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return NULL;
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cha->scurr += cha->isize;
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if (cha->scurr == sncur->icurr) {
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if (!(sncur = cha->sncur = sncur->next))
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return NULL;
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cha->scurr = 0;
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}
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return (char *) sncur + sizeof(chanode_t) + cha->scurr;
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}
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long xdl_guess_lines(mmfile_t *mf) {
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long nl = 0, size, tsize = 0;
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char const *data, *cur, *top;
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if ((cur = data = xdl_mmfile_first(mf, &size)) != NULL) {
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for (top = data + size; nl < XDL_GUESS_NLINES;) {
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if (cur >= top) {
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tsize += (long) (cur - data);
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if (!(cur = data = xdl_mmfile_next(mf, &size)))
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break;
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top = data + size;
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}
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nl++;
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if (!(cur = memchr(cur, '\n', top - cur)))
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cur = top;
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else
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cur++;
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}
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tsize += (long) (cur - data);
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}
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if (nl && tsize)
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nl = xdl_mmfile_size(mf) / (tsize / nl);
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return nl + 1;
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}
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int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
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{
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int i1, i2;
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if (s1 == s2 && !memcmp(l1, l2, s1))
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return 1;
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if (!(flags & XDF_WHITESPACE_FLAGS))
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return 0;
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i1 = 0;
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i2 = 0;
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/*
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* -w matches everything that matches with -b, and -b in turn
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* matches everything that matches with --ignore-space-at-eol.
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*
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* Each flavor of ignoring needs different logic to skip whitespaces
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* while we have both sides to compare.
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*/
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if (flags & XDF_IGNORE_WHITESPACE) {
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goto skip_ws;
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while (i1 < s1 && i2 < s2) {
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if (l1[i1++] != l2[i2++])
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return 0;
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skip_ws:
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while (i1 < s1 && isspace(l1[i1]))
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i1++;
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while (i2 < s2 && isspace(l2[i2]))
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i2++;
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}
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} else if (flags & XDF_IGNORE_WHITESPACE_CHANGE) {
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while (i1 < s1 && i2 < s2) {
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if (isspace(l1[i1]) && isspace(l2[i2])) {
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/* Skip matching spaces and try again */
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while (i1 < s1 && isspace(l1[i1]))
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i1++;
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while (i2 < s2 && isspace(l2[i2]))
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i2++;
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continue;
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}
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if (l1[i1++] != l2[i2++])
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return 0;
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}
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} else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL) {
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while (i1 < s1 && i2 < s2 && l1[i1++] == l2[i2++])
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; /* keep going */
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}
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/*
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* After running out of one side, the remaining side must have
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* nothing but whitespace for the lines to match. Note that
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* ignore-whitespace-at-eol case may break out of the loop
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* while there still are characters remaining on both lines.
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*/
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if (i1 < s1) {
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while (i1 < s1 && isspace(l1[i1]))
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i1++;
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if (s1 != i1)
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return 0;
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}
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if (i2 < s2) {
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while (i2 < s2 && isspace(l2[i2]))
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i2++;
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return (s2 == i2);
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}
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return 1;
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}
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static unsigned long xdl_hash_record_with_whitespace(char const **data,
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char const *top, long flags) {
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unsigned long ha = 5381;
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char const *ptr = *data;
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for (; ptr < top && *ptr != '\n'; ptr++) {
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if (isspace(*ptr)) {
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const char *ptr2 = ptr;
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int at_eol;
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while (ptr + 1 < top && isspace(ptr[1])
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&& ptr[1] != '\n')
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ptr++;
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at_eol = (top <= ptr + 1 || ptr[1] == '\n');
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if (flags & XDF_IGNORE_WHITESPACE)
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; /* already handled */
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else if (flags & XDF_IGNORE_WHITESPACE_CHANGE
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&& !at_eol) {
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ha += (ha << 5);
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ha ^= (unsigned long) ' ';
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}
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else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL
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&& !at_eol) {
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while (ptr2 != ptr + 1) {
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ha += (ha << 5);
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ha ^= (unsigned long) *ptr2;
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ptr2++;
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}
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}
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continue;
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}
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ha += (ha << 5);
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ha ^= (unsigned long) *ptr;
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}
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*data = ptr < top ? ptr + 1: ptr;
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return ha;
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}
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unsigned long xdl_hash_record(char const **data, char const *top, long flags) {
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unsigned long ha = 5381;
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char const *ptr = *data;
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if (flags & XDF_WHITESPACE_FLAGS)
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return xdl_hash_record_with_whitespace(data, top, flags);
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for (; ptr < top && *ptr != '\n'; ptr++) {
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ha += (ha << 5);
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ha ^= (unsigned long) *ptr;
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}
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*data = ptr < top ? ptr + 1: ptr;
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return ha;
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}
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unsigned int xdl_hashbits(unsigned int size) {
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unsigned int val = 1, bits = 0;
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for (; val < size && bits < CHAR_BIT * sizeof(unsigned int); val <<= 1, bits++);
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return bits ? bits: 1;
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}
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int xdl_num_out(char *out, long val) {
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char *ptr, *str = out;
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char buf[32];
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ptr = buf + sizeof(buf) - 1;
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*ptr = '\0';
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if (val < 0) {
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*--ptr = '-';
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val = -val;
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}
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for (; val && ptr > buf; val /= 10)
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*--ptr = "0123456789"[val % 10];
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if (*ptr)
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for (; *ptr; ptr++, str++)
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*str = *ptr;
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else
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*str++ = '0';
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*str = '\0';
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return str - out;
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}
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long xdl_atol(char const *str, char const **next) {
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long val, base;
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char const *top;
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for (top = str; XDL_ISDIGIT(*top); top++);
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if (next)
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*next = top;
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for (val = 0, base = 1, top--; top >= str; top--, base *= 10)
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val += base * (long)(*top - '0');
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return val;
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}
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int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
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const char *func, long funclen, xdemitcb_t *ecb) {
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int nb = 0;
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mmbuffer_t mb;
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char buf[128];
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memcpy(buf, "@@ -", 4);
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nb += 4;
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nb += xdl_num_out(buf + nb, c1 ? s1: s1 - 1);
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if (c1 != 1) {
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memcpy(buf + nb, ",", 1);
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nb += 1;
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nb += xdl_num_out(buf + nb, c1);
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}
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memcpy(buf + nb, " +", 2);
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nb += 2;
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nb += xdl_num_out(buf + nb, c2 ? s2: s2 - 1);
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if (c2 != 1) {
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memcpy(buf + nb, ",", 1);
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nb += 1;
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nb += xdl_num_out(buf + nb, c2);
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}
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memcpy(buf + nb, " @@", 3);
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nb += 3;
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if (func && funclen) {
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buf[nb++] = ' ';
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if (funclen > sizeof(buf) - nb - 1)
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funclen = sizeof(buf) - nb - 1;
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memcpy(buf + nb, func, funclen);
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nb += funclen;
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}
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buf[nb++] = '\n';
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mb.ptr = buf;
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mb.size = nb;
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if (ecb->outf(ecb->priv, &mb, 1) < 0)
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return -1;
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return 0;
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}
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