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-rw-r--r--xdiff/xutils.c495
1 files changed, 495 insertions, 0 deletions
diff --git a/xdiff/xutils.c b/xdiff/xutils.c
new file mode 100644
index 0000000000..62cb23dfd3
--- /dev/null
+++ b/xdiff/xutils.c
@@ -0,0 +1,495 @@
+/*
+ * LibXDiff by Davide Libenzi ( File Differential Library )
+ * Copyright (C) 2003 Davide Libenzi
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#include <limits.h>
+#include <assert.h>
+#include "xinclude.h"
+
+
+
+
+long xdl_bogosqrt(long n) {
+ long i;
+
+ /*
+ * Classical integer square root approximation using shifts.
+ */
+ for (i = 1; n > 0; n >>= 2)
+ i <<= 1;
+
+ return i;
+}
+
+
+int xdl_emit_diffrec(char const *rec, long size, char const *pre, long psize,
+ xdemitcb_t *ecb) {
+ int i = 2;
+ mmbuffer_t mb[3];
+
+ mb[0].ptr = (char *) pre;
+ mb[0].size = psize;
+ mb[1].ptr = (char *) rec;
+ mb[1].size = size;
+ if (size > 0 && rec[size - 1] != '\n') {
+ mb[2].ptr = (char *) "\n\\ No newline at end of file\n";
+ mb[2].size = strlen(mb[2].ptr);
+ i++;
+ }
+ if (ecb->outf(ecb->priv, mb, i) < 0) {
+
+ return -1;
+ }
+
+ return 0;
+}
+
+void *xdl_mmfile_first(mmfile_t *mmf, long *size)
+{
+ *size = mmf->size;
+ return mmf->ptr;
+}
+
+
+long xdl_mmfile_size(mmfile_t *mmf)
+{
+ return mmf->size;
+}
+
+
+int xdl_cha_init(chastore_t *cha, long isize, long icount) {
+
+ cha->head = cha->tail = NULL;
+ cha->isize = isize;
+ cha->nsize = icount * isize;
+ cha->ancur = cha->sncur = NULL;
+ cha->scurr = 0;
+
+ return 0;
+}
+
+
+void xdl_cha_free(chastore_t *cha) {
+ chanode_t *cur, *tmp;
+
+ for (cur = cha->head; (tmp = cur) != NULL;) {
+ cur = cur->next;
+ xdl_free(tmp);
+ }
+}
+
+
+void *xdl_cha_alloc(chastore_t *cha) {
+ chanode_t *ancur;
+ void *data;
+
+ if (!(ancur = cha->ancur) || ancur->icurr == cha->nsize) {
+ if (!(ancur = (chanode_t *) xdl_malloc(sizeof(chanode_t) + cha->nsize))) {
+
+ return NULL;
+ }
+ ancur->icurr = 0;
+ ancur->next = NULL;
+ if (cha->tail)
+ cha->tail->next = ancur;
+ if (!cha->head)
+ cha->head = ancur;
+ cha->tail = ancur;
+ cha->ancur = ancur;
+ }
+
+ data = (char *) ancur + sizeof(chanode_t) + ancur->icurr;
+ ancur->icurr += cha->isize;
+
+ return data;
+}
+
+long xdl_guess_lines(mmfile_t *mf, long sample) {
+ long nl = 0, size, tsize = 0;
+ char const *data, *cur, *top;
+
+ if ((cur = data = xdl_mmfile_first(mf, &size)) != NULL) {
+ for (top = data + size; nl < sample && cur < top; ) {
+ nl++;
+ if (!(cur = memchr(cur, '\n', top - cur)))
+ cur = top;
+ else
+ cur++;
+ }
+ tsize += (long) (cur - data);
+ }
+
+ if (nl && tsize)
+ nl = xdl_mmfile_size(mf) / (tsize / nl);
+
+ return nl + 1;
+}
+
+int xdl_blankline(const char *line, long size, long flags)
+{
+ long i;
+
+ if (!(flags & XDF_WHITESPACE_FLAGS))
+ return (size <= 1);
+
+ for (i = 0; i < size && XDL_ISSPACE(line[i]); i++)
+ ;
+
+ return (i == size);
+}
+
+int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
+{
+ int i1, i2;
+
+ if (s1 == s2 && !memcmp(l1, l2, s1))
+ return 1;
+ if (!(flags & XDF_WHITESPACE_FLAGS))
+ return 0;
+
+ i1 = 0;
+ i2 = 0;
+
+ /*
+ * -w matches everything that matches with -b, and -b in turn
+ * matches everything that matches with --ignore-space-at-eol.
+ *
+ * Each flavor of ignoring needs different logic to skip whitespaces
+ * while we have both sides to compare.
+ */
+ if (flags & XDF_IGNORE_WHITESPACE) {
+ goto skip_ws;
+ while (i1 < s1 && i2 < s2) {
+ if (l1[i1++] != l2[i2++])
+ return 0;
+ skip_ws:
+ while (i1 < s1 && XDL_ISSPACE(l1[i1]))
+ i1++;
+ while (i2 < s2 && XDL_ISSPACE(l2[i2]))
+ i2++;
+ }
+ } else if (flags & XDF_IGNORE_WHITESPACE_CHANGE) {
+ while (i1 < s1 && i2 < s2) {
+ if (XDL_ISSPACE(l1[i1]) && XDL_ISSPACE(l2[i2])) {
+ /* Skip matching spaces and try again */
+ while (i1 < s1 && XDL_ISSPACE(l1[i1]))
+ i1++;
+ while (i2 < s2 && XDL_ISSPACE(l2[i2]))
+ i2++;
+ continue;
+ }
+ if (l1[i1++] != l2[i2++])
+ return 0;
+ }
+ } else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL) {
+ while (i1 < s1 && i2 < s2 && l1[i1++] == l2[i2++])
+ ; /* keep going */
+ }
+
+ /*
+ * After running out of one side, the remaining side must have
+ * nothing but whitespace for the lines to match. Note that
+ * ignore-whitespace-at-eol case may break out of the loop
+ * while there still are characters remaining on both lines.
+ */
+ if (i1 < s1) {
+ while (i1 < s1 && XDL_ISSPACE(l1[i1]))
+ i1++;
+ if (s1 != i1)
+ return 0;
+ }
+ if (i2 < s2) {
+ while (i2 < s2 && XDL_ISSPACE(l2[i2]))
+ i2++;
+ return (s2 == i2);
+ }
+ return 1;
+}
+
+static unsigned long xdl_hash_record_with_whitespace(char const **data,
+ char const *top, long flags) {
+ unsigned long ha = 5381;
+ char const *ptr = *data;
+
+ for (; ptr < top && *ptr != '\n'; ptr++) {
+ if (XDL_ISSPACE(*ptr)) {
+ const char *ptr2 = ptr;
+ int at_eol;
+ while (ptr + 1 < top && XDL_ISSPACE(ptr[1])
+ && ptr[1] != '\n')
+ ptr++;
+ at_eol = (top <= ptr + 1 || ptr[1] == '\n');
+ if (flags & XDF_IGNORE_WHITESPACE)
+ ; /* already handled */
+ else if (flags & XDF_IGNORE_WHITESPACE_CHANGE
+ && !at_eol) {
+ ha += (ha << 5);
+ ha ^= (unsigned long) ' ';
+ }
+ else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL
+ && !at_eol) {
+ while (ptr2 != ptr + 1) {
+ ha += (ha << 5);
+ ha ^= (unsigned long) *ptr2;
+ ptr2++;
+ }
+ }
+ continue;
+ }
+ ha += (ha << 5);
+ ha ^= (unsigned long) *ptr;
+ }
+ *data = ptr < top ? ptr + 1: ptr;
+
+ return ha;
+}
+
+#ifdef XDL_FAST_HASH
+
+#define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
+
+#define ONEBYTES REPEAT_BYTE(0x01)
+#define NEWLINEBYTES REPEAT_BYTE(0x0a)
+#define HIGHBITS REPEAT_BYTE(0x80)
+
+/* Return the high bit set in the first byte that is a zero */
+static inline unsigned long has_zero(unsigned long a)
+{
+ return ((a - ONEBYTES) & ~a) & HIGHBITS;
+}
+
+static inline long count_masked_bytes(unsigned long mask)
+{
+ if (sizeof(long) == 8) {
+ /*
+ * Jan Achrenius on G+: microoptimized version of
+ * the simpler "(mask & ONEBYTES) * ONEBYTES >> 56"
+ * that works for the bytemasks without having to
+ * mask them first.
+ */
+ /*
+ * return mask * 0x0001020304050608 >> 56;
+ *
+ * Doing it like this avoids warnings on 32-bit machines.
+ */
+ long a = (REPEAT_BYTE(0x01) / 0xff + 1);
+ return mask * a >> (sizeof(long) * 7);
+ } else {
+ /* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
+ /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
+ long a = (0x0ff0001 + mask) >> 23;
+ /* Fix the 1 for 00 case */
+ return a & mask;
+ }
+}
+
+unsigned long xdl_hash_record(char const **data, char const *top, long flags)
+{
+ unsigned long hash = 5381;
+ unsigned long a = 0, mask = 0;
+ char const *ptr = *data;
+ char const *end = top - sizeof(unsigned long) + 1;
+
+ if (flags & XDF_WHITESPACE_FLAGS)
+ return xdl_hash_record_with_whitespace(data, top, flags);
+
+ ptr -= sizeof(unsigned long);
+ do {
+ hash += hash << 5;
+ hash ^= a;
+ ptr += sizeof(unsigned long);
+ if (ptr >= end)
+ break;
+ a = *(unsigned long *)ptr;
+ /* Do we have any '\n' bytes in this word? */
+ mask = has_zero(a ^ NEWLINEBYTES);
+ } while (!mask);
+
+ if (ptr >= end) {
+ /*
+ * There is only a partial word left at the end of the
+ * buffer. Because we may work with a memory mapping,
+ * we have to grab the rest byte by byte instead of
+ * blindly reading it.
+ *
+ * To avoid problems with masking in a signed value,
+ * we use an unsigned char here.
+ */
+ const char *p;
+ for (p = top - 1; p >= ptr; p--)
+ a = (a << 8) + *((const unsigned char *)p);
+ mask = has_zero(a ^ NEWLINEBYTES);
+ if (!mask)
+ /*
+ * No '\n' found in the partial word. Make a
+ * mask that matches what we read.
+ */
+ mask = 1UL << (8 * (top - ptr) + 7);
+ }
+
+ /* The mask *below* the first high bit set */
+ mask = (mask - 1) & ~mask;
+ mask >>= 7;
+ hash += hash << 5;
+ hash ^= a & mask;
+
+ /* Advance past the last (possibly partial) word */
+ ptr += count_masked_bytes(mask);
+
+ if (ptr < top) {
+ assert(*ptr == '\n');
+ ptr++;
+ }
+
+ *data = ptr;
+
+ return hash;
+}
+
+#else /* XDL_FAST_HASH */
+
+unsigned long xdl_hash_record(char const **data, char const *top, long flags) {
+ unsigned long ha = 5381;
+ char const *ptr = *data;
+
+ if (flags & XDF_WHITESPACE_FLAGS)
+ return xdl_hash_record_with_whitespace(data, top, flags);
+
+ for (; ptr < top && *ptr != '\n'; ptr++) {
+ ha += (ha << 5);
+ ha ^= (unsigned long) *ptr;
+ }
+ *data = ptr < top ? ptr + 1: ptr;
+
+ return ha;
+}
+
+#endif /* XDL_FAST_HASH */
+
+unsigned int xdl_hashbits(unsigned int size) {
+ unsigned int val = 1, bits = 0;
+
+ for (; val < size && bits < CHAR_BIT * sizeof(unsigned int); val <<= 1, bits++);
+ return bits ? bits: 1;
+}
+
+
+int xdl_num_out(char *out, long val) {
+ char *ptr, *str = out;
+ char buf[32];
+
+ ptr = buf + sizeof(buf) - 1;
+ *ptr = '\0';
+ if (val < 0) {
+ *--ptr = '-';
+ val = -val;
+ }
+ for (; val && ptr > buf; val /= 10)
+ *--ptr = "0123456789"[val % 10];
+ if (*ptr)
+ for (; *ptr; ptr++, str++)
+ *str = *ptr;
+ else
+ *str++ = '0';
+ *str = '\0';
+
+ return str - out;
+}
+
+int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
+ const char *func, long funclen, xdemitcb_t *ecb) {
+ int nb = 0;
+ mmbuffer_t mb;
+ char buf[128];
+
+ memcpy(buf, "@@ -", 4);
+ nb += 4;
+
+ nb += xdl_num_out(buf + nb, c1 ? s1: s1 - 1);
+
+ if (c1 != 1) {
+ memcpy(buf + nb, ",", 1);
+ nb += 1;
+
+ nb += xdl_num_out(buf + nb, c1);
+ }
+
+ memcpy(buf + nb, " +", 2);
+ nb += 2;
+
+ nb += xdl_num_out(buf + nb, c2 ? s2: s2 - 1);
+
+ if (c2 != 1) {
+ memcpy(buf + nb, ",", 1);
+ nb += 1;
+
+ nb += xdl_num_out(buf + nb, c2);
+ }
+
+ memcpy(buf + nb, " @@", 3);
+ nb += 3;
+ if (func && funclen) {
+ buf[nb++] = ' ';
+ if (funclen > sizeof(buf) - nb - 1)
+ funclen = sizeof(buf) - nb - 1;
+ memcpy(buf + nb, func, funclen);
+ nb += funclen;
+ }
+ buf[nb++] = '\n';
+
+ mb.ptr = buf;
+ mb.size = nb;
+ if (ecb->outf(ecb->priv, &mb, 1) < 0)
+ return -1;
+
+ return 0;
+}
+
+int xdl_fall_back_diff(xdfenv_t *diff_env, xpparam_t const *xpp,
+ int line1, int count1, int line2, int count2)
+{
+ /*
+ * This probably does not work outside Git, since
+ * we have a very simple mmfile structure.
+ *
+ * Note: ideally, we would reuse the prepared environment, but
+ * the libxdiff interface does not (yet) allow for diffing only
+ * ranges of lines instead of the whole files.
+ */
+ mmfile_t subfile1, subfile2;
+ xdfenv_t env;
+
+ subfile1.ptr = (char *)diff_env->xdf1.recs[line1 - 1]->ptr;
+ subfile1.size = diff_env->xdf1.recs[line1 + count1 - 2]->ptr +
+ diff_env->xdf1.recs[line1 + count1 - 2]->size - subfile1.ptr;
+ subfile2.ptr = (char *)diff_env->xdf2.recs[line2 - 1]->ptr;
+ subfile2.size = diff_env->xdf2.recs[line2 + count2 - 2]->ptr +
+ diff_env->xdf2.recs[line2 + count2 - 2]->size - subfile2.ptr;
+ if (xdl_do_diff(&subfile1, &subfile2, xpp, &env) < 0)
+ return -1;
+
+ memcpy(diff_env->xdf1.rchg + line1 - 1, env.xdf1.rchg, count1);
+ memcpy(diff_env->xdf2.rchg + line2 - 1, env.xdf2.rchg, count2);
+
+ xdl_free_env(&env);
+
+ return 0;
+}
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