зеркало из https://github.com/microsoft/git.git
483 строки
11 KiB
C
483 строки
11 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 <limits.h>
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#include <assert.h>
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#include "xinclude.h"
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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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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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long xdl_guess_lines(mmfile_t *mf, long sample) {
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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 < sample && cur < top; ) {
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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 && XDL_ISSPACE(l1[i1]))
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i1++;
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while (i2 < s2 && XDL_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 (XDL_ISSPACE(l1[i1]) && XDL_ISSPACE(l2[i2])) {
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/* Skip matching spaces and try again */
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while (i1 < s1 && XDL_ISSPACE(l1[i1]))
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i1++;
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while (i2 < s2 && XDL_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 && XDL_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 && XDL_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 (XDL_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 && XDL_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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#ifdef XDL_FAST_HASH
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#define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
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#define ONEBYTES REPEAT_BYTE(0x01)
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#define NEWLINEBYTES REPEAT_BYTE(0x0a)
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#define HIGHBITS REPEAT_BYTE(0x80)
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/* Return the high bit set in the first byte that is a zero */
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static inline unsigned long has_zero(unsigned long a)
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{
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return ((a - ONEBYTES) & ~a) & HIGHBITS;
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}
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static inline long count_masked_bytes(unsigned long mask)
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{
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if (sizeof(long) == 8) {
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/*
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* Jan Achrenius on G+: microoptimized version of
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* the simpler "(mask & ONEBYTES) * ONEBYTES >> 56"
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* that works for the bytemasks without having to
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* mask them first.
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*/
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/*
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* return mask * 0x0001020304050608 >> 56;
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*
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* Doing it like this avoids warnings on 32-bit machines.
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*/
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long a = (REPEAT_BYTE(0x01) / 0xff + 1);
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return mask * a >> (sizeof(long) * 7);
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} else {
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/* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
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/* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
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long a = (0x0ff0001 + mask) >> 23;
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/* Fix the 1 for 00 case */
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return a & mask;
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}
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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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{
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unsigned long hash = 5381;
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unsigned long a = 0, mask = 0;
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char const *ptr = *data;
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char const *end = top - sizeof(unsigned long) + 1;
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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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ptr -= sizeof(unsigned long);
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do {
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hash += hash << 5;
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hash ^= a;
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ptr += sizeof(unsigned long);
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if (ptr >= end)
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break;
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a = *(unsigned long *)ptr;
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/* Do we have any '\n' bytes in this word? */
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mask = has_zero(a ^ NEWLINEBYTES);
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} while (!mask);
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if (ptr >= end) {
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/*
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* There is only a partial word left at the end of the
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* buffer. Because we may work with a memory mapping,
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* we have to grab the rest byte by byte instead of
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* blindly reading it.
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*
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* To avoid problems with masking in a signed value,
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* we use an unsigned char here.
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*/
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const char *p;
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for (p = top - 1; p >= ptr; p--)
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a = (a << 8) + *((const unsigned char *)p);
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mask = has_zero(a ^ NEWLINEBYTES);
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if (!mask)
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/*
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* No '\n' found in the partial word. Make a
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* mask that matches what we read.
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*/
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mask = 1UL << (8 * (top - ptr) + 7);
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}
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/* The mask *below* the first high bit set */
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mask = (mask - 1) & ~mask;
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mask >>= 7;
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hash += hash << 5;
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hash ^= a & mask;
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/* Advance past the last (possibly partial) word */
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ptr += count_masked_bytes(mask);
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if (ptr < top) {
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assert(*ptr == '\n');
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ptr++;
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}
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*data = ptr;
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return hash;
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}
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#else /* XDL_FAST_HASH */
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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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#endif /* XDL_FAST_HASH */
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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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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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int xdl_fall_back_diff(xdfenv_t *diff_env, xpparam_t const *xpp,
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int line1, int count1, int line2, int count2)
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{
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/*
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* This probably does not work outside Git, since
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* we have a very simple mmfile structure.
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*
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* Note: ideally, we would reuse the prepared environment, but
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* the libxdiff interface does not (yet) allow for diffing only
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* ranges of lines instead of the whole files.
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*/
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mmfile_t subfile1, subfile2;
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xdfenv_t env;
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subfile1.ptr = (char *)diff_env->xdf1.recs[line1 - 1]->ptr;
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subfile1.size = diff_env->xdf1.recs[line1 + count1 - 2]->ptr +
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diff_env->xdf1.recs[line1 + count1 - 2]->size - subfile1.ptr;
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subfile2.ptr = (char *)diff_env->xdf2.recs[line2 - 1]->ptr;
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subfile2.size = diff_env->xdf2.recs[line2 + count2 - 2]->ptr +
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diff_env->xdf2.recs[line2 + count2 - 2]->size - subfile2.ptr;
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if (xdl_do_diff(&subfile1, &subfile2, xpp, &env) < 0)
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return -1;
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memcpy(diff_env->xdf1.rchg + line1 - 1, env.xdf1.rchg, count1);
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memcpy(diff_env->xdf2.rchg + line2 - 1, env.xdf2.rchg, count2);
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xdl_free_env(&env);
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return 0;
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}
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