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/* See LICENSE file for copyright and license details. */
#include "common.h"
#define REPETITION_MAX ((1U << (sizeof(int) * CHAR_BIT - CHAR_BIT)) - 1U)
static int
allocate(struct libpatch_diff2 **diff, size_t *difflen, size_t *r, size_t *w, int change)
{
#define GROWTH 32U
void *new;
size_t size;
if (*w == *r) {
if (GROWTH > SIZE_MAX / sizeof(**diff) - *difflen) {
errno = ENOMEM;
return -1;
}
size = (*difflen + GROWTH) * sizeof(**diff);
new = realloc(*diff, size);
if (!new)
return -1;
*diff = new;
memmove(&(*diff)[*r + GROWTH], &(*diff)[*r], *difflen - *r);
*difflen += GROWTH;
*r += GROWTH;
}
(*diff)[*w].change = (unsigned char)change;
(*diff)[*w].repetition = 0;
*w += 1;
return 0;
}
static int
putchange(struct libpatch_diff2 **diff, size_t *difflen, size_t *r, size_t *w, int change, size_t count)
{
if (!count)
return 0;
if (*w && (*diff)[*w - 1].change == change && (*diff)[*w - 1].repetition < REPETITION_MAX)
goto start;
do {
if (allocate(diff, difflen, r, w, change))
return -1;
start:
if (count > (size_t)(REPETITION_MAX - (*diff)[*w - 1].repetition)) {
count -= (size_t)(REPETITION_MAX - (*diff)[*w - 1].repetition);
(*diff)[*w - 1].repetition = REPETITION_MAX;
} else {
(*diff)[*w - 1].repetition += count;
break;
}
} while (count);
return 0;
}
static int
put(struct libpatch_diff2 **diff, size_t *difflen,
const struct libpatch_diff2_spec *spec, size_t *r, size_t *w,
size_t common, size_t onlyfile1, size_t onlyfile2, size_t changed)
{
int a, b;
size_t an, bn, i;
size_t context, a_context, z_context;
if (common) {
if (spec->full_context) {
return putchange(diff, difflen, r, w, LIBPATCH_DIFF2_CONTEXT, common);
} else if (*w > 0 && *r < *difflen) {
context = MAX(spec->context_after + spec->context_before, spec->context_between);
if (common <= context)
return putchange(diff, difflen, r, w, LIBPATCH_DIFF2_CONTEXT, common);
common -= a_context = MIN(spec->context_after, common);
common -= z_context = MIN(spec->context_before, common);
return -(putchange(diff, difflen, r, w, LIBPATCH_DIFF2_CONTEXT, a_context) ||
putchange(diff, difflen, r, w, LIBPATCH_DIFF2_SKIP, common) ||
putchange(diff, difflen, r, w, LIBPATCH_DIFF2_CONTEXT, z_context));
} else if (*w > 0) {
common -= context = MIN(spec->context_after, common);
return -(putchange(diff, difflen, r, w, LIBPATCH_DIFF2_CONTEXT, context) ||
putchange(diff, difflen, r, w, LIBPATCH_DIFF2_SKIP, common));
} else if (*r < *difflen) {
common -= context = MIN(spec->context_before, common);
return -(putchange(diff, difflen, r, w, LIBPATCH_DIFF2_SKIP, common) ||
putchange(diff, difflen, r, w, LIBPATCH_DIFF2_CONTEXT, context));
} else {
return putchange(diff, difflen, r, w, LIBPATCH_DIFF2_SKIP, common);
}
} else {
if (!spec->keep_split_changes) {
changed += MIN(onlyfile1, onlyfile2);
onlyfile1 -= changed;
onlyfile2 -= changed;
}
if (spec->single_file_change_order == LIBPATCH_DIFF2_FILE1_ONLY_FIRST) {
a = LIBPATCH_DIFF2_FILE1_ONLY;
an = onlyfile1;
b = LIBPATCH_DIFF2_FILE2_ONLY;
bn = onlyfile2;
} else {
a = LIBPATCH_DIFF2_FILE2_ONLY;
an = onlyfile2;
b = LIBPATCH_DIFF2_FILE1_ONLY;
bn = onlyfile1;
}
if (spec->two_file_change_order == LIBPATCH_DIFF2_TWO_FILE_CHANGES_BEFORE_SINGLE_FILE)
if (putchange(diff, difflen, r, w, LIBPATCH_DIFF2_TWO_FILE_CHANGE, changed))
return -1;
if (putchange(diff, difflen, r, w, a, an))
return -1;
if (spec->two_file_change_order == LIBPATCH_DIFF2_NO_TWO_FILE_CHANGES) {
if (putchange(diff, difflen, r, w, a, changed))
return -1;
if (putchange(diff, difflen, r, w, b, changed))
return -1;
} else if (spec->two_file_change_order == LIBPATCH_DIFF2_NO_TWO_FILE_CHANGES_INTERLEAVE) {
for (i = 0; i < changed; i++) {
if (putchange(diff, difflen, r, w, a, 1))
return -1;
if (putchange(diff, difflen, r, w, b, 1))
return -1;
}
}
if (spec->two_file_change_order == LIBPATCH_DIFF2_TWO_FILE_CHANGES_BETWEEN_SINGLE_FILE)
if (putchange(diff, difflen, r, w, LIBPATCH_DIFF2_TWO_FILE_CHANGE, changed))
return -1;
if (putchange(diff, difflen, r, w, b, bn))
return -1;
if (spec->two_file_change_order == LIBPATCH_DIFF2_TWO_FILE_CHANGES_AFTER_SINGLE_FILE)
if (putchange(diff, difflen, r, w, LIBPATCH_DIFF2_TWO_FILE_CHANGE, changed))
return -1;
return 0;
}
}
int
libpatch_rewrite_diff2(struct libpatch_diff2 **diff, size_t *difflen,
const struct libpatch_diff2_spec *spec)
{
size_t r, w = 0;
size_t saved0 = 0, saved1 = 0, saved2 = 0, saved3 = 0;
for (r = 0; r < *difflen; r++) {
if ((*diff)[r].change == LIBPATCH_DIFF2_SKIP ||
(*diff)[r].change == LIBPATCH_DIFF2_CONTEXT) {
if (saved1 || saved2) {
if (put(diff, difflen, spec, &r, &w, saved0, saved1, saved2, saved3))
return -1;
saved1 = 0;
saved2 = 0;
saved3 = 0;
}
saved0 += (size_t)(*diff)[r].repetition;
} else {
if (saved0) {
if (put(diff, difflen, spec, &r, &w, saved0, saved1, saved2, saved3))
return -1;
saved0 = 0;
}
if (spec->keep_split_changes) {
if ((*diff)[r].change == LIBPATCH_DIFF2_FILE1_ONLY)
saved1 += (size_t)(*diff)[r].repetition;
else if ((*diff)[r].change == LIBPATCH_DIFF2_FILE2_ONLY)
saved2 += (size_t)(*diff)[r].repetition;
else
saved3 += (size_t)(*diff)[r].repetition;
} else {
if ((*diff)[r].change != LIBPATCH_DIFF2_FILE2_ONLY)
saved1 += (size_t)(*diff)[r].repetition;
if ((*diff)[r].change != LIBPATCH_DIFF2_FILE1_ONLY)
saved2 += (size_t)(*diff)[r].repetition;
}
}
}
if (put(diff, difflen, spec, &r, &w, saved0, saved1, saved2, saved3))
return -1;
*difflen = w;
return 0;
}
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