--- /dev/null
+/*
+ * Copyright (C) 2011 Joseph Adams <joeyadams3.14159@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "bdelta.h"
+
+#include <assert.h>
+#include <limits.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+typedef struct
+{
+ unsigned char *cur; /* End of string; insertion point for new bytes */
+ unsigned char *end; /* End of buffer */
+ unsigned char *start; /* Beginning of string */
+} SB;
+
+/* sb is evaluated multiple times in these macros. */
+#define sb_size(sb) ((size_t)((sb)->cur - (sb)->start))
+#define sb_avail(sb) ((size_t)((sb)->end - (sb)->cur))
+
+/* sb and need may be evaluated multiple times. */
+#define sb_need(sb, need) do { \
+ if (sb_avail(sb) < (need)) \
+ if (sb_grow(sb, need) != 0) \
+ goto out_of_memory; \
+ } while (0)
+
+static int sb_init(SB *sb)
+{
+ sb->start = malloc(17);
+ if (sb->start == NULL)
+ return -1;
+ sb->cur = sb->start;
+ sb->end = sb->start + 16;
+ return 0;
+}
+
+static int sb_grow(SB *sb, size_t need)
+{
+ size_t length = sb->cur - sb->start;
+ size_t alloc = sb->end - sb->start;
+ unsigned char *tmp;
+
+ do {
+ alloc *= 2;
+ } while (alloc < length + need);
+
+ tmp = realloc(sb->start, alloc + 1);
+ if (tmp == NULL)
+ return -1;
+ sb->start = tmp;
+ sb->cur = tmp + length;
+ sb->end = tmp + alloc;
+ return 0;
+}
+
+static int sb_putc(SB *sb, unsigned char c)
+{
+ sb_need(sb, 1);
+ *sb->cur++ = c;
+ return 0;
+
+out_of_memory:
+ return -1;
+}
+
+static int sb_write(SB *sb, const void *data, size_t size)
+{
+ sb_need(sb, size);
+ memcpy(sb->cur, data, size);
+ sb->cur += size;
+ return 0;
+
+out_of_memory:
+ return -1;
+}
+
+static void sb_return(SB *sb, void **data_out, size_t *length_out)
+{
+ *sb->cur = 0;
+ if (data_out)
+ *data_out = sb->start;
+ else
+ free(sb->start);
+ if (length_out)
+ *length_out = sb->cur - sb->start;
+}
+
+static void sb_discard(SB *sb, void **data_out, size_t *length_out)
+{
+ free(sb->start);
+ if (data_out)
+ *data_out = NULL;
+ if (length_out)
+ *length_out = 0;
+}
+
+/*
+ * The first byte in a patch is the "patch type", which indicates how the
+ * patch is formatted. This keeps the patch format flexible while retaining
+ * backward compatibility. Patches produced with an older version of
+ * the library can be applied with a newer version.
+ *
+ * PT_LITERAL
+ * Contains nothing more than the content of the new text.
+ *
+ * PT_CSI32
+ * A string of copy, skip, and insert instructions for generating the new
+ * string from the old.
+ *
+ * copy(size): Copy @size bytes from old to new.
+ * skip(size): Skip @size bytes of old.
+ * insert(text): Insert @text into new.
+ *
+ * The syntax is as follows:
+ *
+ * copy: instruction_byte(1) size
+ * skip: instruction_byte(2) size
+ * insert: instruction_byte(3) size $size*OCTET
+ *
+ * 0 <= size_param_length <= 4
+ * instruction_byte(op) = op | size_param_length << 2
+ * size: $size_param_length*OCTET
+ * -- size is an unsigned integer encoded in big endian.
+ * -- However, if size_param_length is 0, the operation size is 1.
+ *
+ * Simply put, an instruction starts with an opcode and operation size.
+ * An insert instruction is followed by the bytes to be inserted.
+ */
+#define PT_LITERAL 10
+#define PT_CSI32 11
+
+#define OP_COPY 1
+#define OP_SKIP 2
+#define OP_INSERT 3
+
+static unsigned int bytes_needed_for_size(uint32_t size)
+{
+ if (size == 1)
+ return 0;
+ else if (size <= 0xFF)
+ return 1;
+ else if (size <= 0xFFFF)
+ return 2;
+ else if (size <= 0xFFFFFF)
+ return 3;
+ else
+ return 4;
+}
+
+/*
+ * Return values:
+ *
+ * BDELTA_OK: Success
+ * BDELTA_MEMORY: Memory allocation failed
+ */
+static BDELTAcode csi32_emit_op(SB *patch_out, int op, uint32_t size, const char **new_)
+{
+ unsigned int i;
+ unsigned int size_param_length;
+ size_t need;
+ uint32_t tmp;
+
+ assert(op >= 1 && op <= 3);
+
+ if (size == 0)
+ return BDELTA_OK;
+ size_param_length = bytes_needed_for_size(size);
+
+ need = 1 + size_param_length;
+ if (op == OP_INSERT)
+ need += size;
+ sb_need(patch_out, need);
+
+ *patch_out->cur++ = (unsigned int)op | size_param_length << 2;
+ for (i = size_param_length, tmp = size; i-- > 0; tmp >>= 8)
+ patch_out->cur[i] = tmp & 0xFF;
+ patch_out->cur += size_param_length;
+
+ switch (op) {
+ case OP_COPY:
+ *new_ += size;
+ break;
+ case OP_SKIP:
+ break;
+ case OP_INSERT:
+ memcpy(patch_out->cur, *new_, size);
+ patch_out->cur += size;
+ *new_ += size;
+ break;
+ default:
+ assert(0);
+ }
+
+ return BDELTA_OK;
+
+out_of_memory:
+ return BDELTA_MEMORY;
+}
+
+/*
+ * On success, returns 1, advances *sp past the parsed text, and sets *op_out and *size_out.
+ * On error or EOF, returns 0.
+ */
+static int csi32_parse_op(
+ const unsigned char **sp, const unsigned char *e,
+ int *op_out, uint32_t *size_out)
+{
+ const unsigned char *s = *sp;
+ int op;
+ unsigned int i;
+ unsigned int size_param_length;
+ uint32_t size;
+
+ if (s >= e)
+ return 0;
+ op = *s & 3;
+ size_param_length = *s >> 2;
+ s++;
+ if (op == 0 || size_param_length > 4)
+ return 0;
+
+ if (size_param_length == 0) {
+ size = 1;
+ } else {
+ if ((size_t)(e - s) < size_param_length)
+ return 0;
+ size = 0;
+ for (i = 0; i < size_param_length; i++) {
+ size <<= 8;
+ size |= *s++ & 0xFF;
+ }
+ }
+
+ /* Make sure insert data fits in the patch, but don't consume it. */
+ if (op == OP_INSERT && (size_t)(e - s) < size)
+ return 0;
+
+ *op_out = op;
+ *size_out = size;
+ *sp = s;
+ return 1;
+}
+
+/*
+ * bdelta uses the algorithm described in:
+ *
+ * Myers, E. (1986). An O(ND) Difference Algorithm and Its Variations.
+ * Retrieved from http://www.xmailserver.org/diff2.pdf
+ *
+ * The pseudocode in Myers' paper (Figure 2) uses an array called V,
+ * where (V[k], V[k] - k) is the endpoint of the furthest-reaching
+ * D-path ending on diagonal k.
+ *
+ * The structure below holds the V array for every iteration of the outer loop.
+ * Because each iteration produces D+1 values, a triangle is formed:
+ *
+ * k
+ * -5 -4 -3 -2 -1 0 1 2 3 4 5
+ * ----------------------------------
+ * 0 | 0 (copy 0)
+ * | \ skip 1
+ * 1 | 0 1
+ * | \ skip 1, then copy 1
+ * 2 | 2 2 3
+ * D | / insert 1, then copy 2
+ * 3 | 3 4 5 5
+ * | \ skip 1, then copy 1
+ * 4 | 3 4 5 7 7
+ * | / insert 1
+ * 5 | 3 4 5 7 - -
+ *
+ * @data will literally contain: 0 0 1 2 2 3 3 4 5 5 3 4 5 7 7 3 4 5 7
+ *
+ * To convert this to an edit script, we first climb back to the top,
+ * using the same procedure as was used when the triangle was generated:
+ *
+ * If k = -D, climb right (the only way we can go).
+ * If k = +D, climb left (the only way we can go).
+ * Otherwise, favor the greater number.
+ * If the numbers are the same, climb left.
+ *
+ * Finally, we convert the descent to the solution to a patch script:
+ *
+ * The top number n corresponds to:
+ * copy n
+ *
+ * A descent left from a to b corresponds to:
+ * insert 1
+ * copy b-a
+ *
+ * A descent right from a to b corresponds to:
+ * skip 1
+ * copy b-a-1
+ */
+typedef struct
+{
+ uint32_t *data;
+ int solution_d;
+ int solution_k;
+ uint32_t *solution_ptr;
+} Triangle;
+
+/*
+ * Return values:
+ *
+ * BDELTA_OK: Success
+ * BDELTA_MEMORY: Memory allocation failed
+ * BDELTA_INTERNAL_DMAX_EXCEEDED: d_max exceeded (strings are too different)
+ */
+static BDELTAcode build_triangle(
+ const char *old, uint32_t old_size,
+ const char *new_, uint32_t new_size,
+ int d_max,
+ Triangle *triangle_out)
+{
+ int d, k;
+ uint32_t x, y;
+ uint32_t *data;
+ uint32_t *vprev; /* position within previous row */
+ uint32_t *v; /* position within current row */
+ uint32_t *vcur; /* beginning of current row */
+ size_t data_alloc = 16;
+
+ memset(triangle_out, 0, sizeof(*triangle_out));
+
+ data = malloc(data_alloc * sizeof(*data));
+ if (data == NULL)
+ return BDELTA_MEMORY;
+
+ /* Allow dmax < 0 to mean "no limit". */
+ if (d_max < 0)
+ d_max = old_size + new_size;
+
+ /*
+ * Compute the farthest-reaching 0-path so the loop after this
+ * will have a "previous" row to start with.
+ */
+ for (x = 0; x < old_size && x < new_size && old[x] == new_[x]; )
+ x++;
+ *data = x;
+ if (x >= old_size && x >= new_size) {
+ /* Strings are equal, so return a triangle with one row (a dot). */
+ assert(x == old_size && x == new_size);
+ triangle_out->data = data;
+ triangle_out->solution_d = 0;
+ triangle_out->solution_k = 0;
+ triangle_out->solution_ptr = data;
+ return BDELTA_OK;
+ }
+ vprev = data;
+ vcur = v = data + 1;
+
+ /*
+ * Here is the core of the Myers diff algorithm.
+ *
+ * This is a direct translation of the pseudocode in Myers' paper,
+ * with implementation-specific adaptations:
+ *
+ * * Every V array is preserved per iteration of the outer loop.
+ * This is necessary so we can determine the actual patch, not just
+ * the length of the shortest edit string. See the coment above
+ * the definition of Triangle for an in-depth explanation.
+ *
+ * * Array items are stored consecutively so as to not waste space.
+ *
+ * * The buffer holding the V arrays is expanded dynamically.
+ */
+ for (d = 1; d <= d_max; d++, vprev = vcur, vcur = v) {
+ /* Ensure that the buffer has enough room for this row. */
+ if ((size_t)(v - data + d + 1) > data_alloc) {
+ size_t vprev_idx = vprev - data;
+ size_t v_idx = v - data;
+ size_t vcur_idx = vcur - data;
+ uint32_t *tmp;
+
+ do {
+ data_alloc *= 2;
+ } while ((size_t)(v - data + d + 1) > data_alloc);
+
+ tmp = realloc(data, data_alloc * sizeof(*data));
+ if (tmp == NULL) {
+ free(data);
+ return BDELTA_MEMORY;
+ }
+ data = tmp;
+
+ /* Relocate pointers to the buffer we just expanded. */
+ vprev = data + vprev_idx;
+ v = data + v_idx;
+ vcur = data + vcur_idx;
+ }
+
+ for (k = -d; k <= d; k += 2, vprev++) {
+ if (k == -d || (k != d && vprev[-1] < vprev[0]))
+ x = vprev[0];
+ else
+ x = vprev[-1] + 1;
+ y = x - k;
+ while (x < old_size && y < new_size && old[x] == new_[y])
+ x++, y++;
+ *v++ = x;
+ if (x >= old_size && y >= new_size) {
+ /* Shortest edit string found. */
+ assert(x == old_size && y == new_size);
+ triangle_out->data = data;
+ triangle_out->solution_d = d;
+ triangle_out->solution_k = k;
+ triangle_out->solution_ptr = v - 1;
+ return BDELTA_OK;
+ }
+ }
+ }
+
+ free(data);
+ return BDELTA_INTERNAL_DMAX_EXCEEDED;
+}
+
+/*
+ * Trace a solution back to the top, returning a string of instructions
+ * for descending from the top to the solution.
+ *
+ * An instruction is one of the following:
+ *
+ * -1: Descend left.
+ * +1: Descend right.
+ * 0: Finished. You should be at the solution now.
+ *
+ * If memory allocation fails, this function will return NULL.
+ */
+static signed char *climb_triangle(const Triangle *triangle)
+{
+ signed char *descent;
+ int d, k;
+ uint32_t *p;
+
+ assert(triangle->solution_d >= 0);
+
+ descent = malloc(triangle->solution_d + 1);
+ if (descent == NULL)
+ return NULL;
+ d = triangle->solution_d;
+ k = triangle->solution_k;
+ p = triangle->solution_ptr;
+ descent[d] = 0;
+
+ while (d > 0) {
+ if (k == -d || (k != d && *(p-d-1) < *(p-d))) {
+ /* Climb right */
+ k++;
+ p = p - d;
+ descent[--d] = -1;
+ } else {
+ /* Climb left */
+ k--;
+ p = p - d - 1;
+ descent[--d] = 1;
+ }
+ }
+
+ return descent;
+}
+
+/*
+ * Generate the actual patch, given data produced by build_triangle and
+ * climb_triangle. new_ is needed for the content of the insertions.
+ *
+ * See the comment above the definition of Triangle. It concisely documents
+ * how a descent down the triangle corresponds to a patch script.
+ *
+ * The resulting patch, including the patch type byte, is appended to patch_out.
+ *
+ * Return values:
+ *
+ * BDELTA_OK: Success
+ * BDELTA_MEMORY: Memory allocation failed
+ */
+static BDELTAcode descent_to_patch(
+ const signed char *descent,
+ const Triangle *triangle,
+ const char *new_, uint32_t new_size,
+ SB *patch_out)
+{
+ const char *new_end = new_ + new_size;
+ uint32_t *p = triangle->data;
+ uint32_t *p2;
+ int d = 0;
+ int k = 0;
+ int pending_op = 0;
+ int current_op;
+ uint32_t pending_length = 0;
+ uint32_t copy_length;
+
+ if (sb_putc(patch_out, PT_CSI32) != 0)
+ return BDELTA_MEMORY;
+
+ if (*p > 0) {
+ if (csi32_emit_op(patch_out, OP_COPY, *p, &new_) != BDELTA_OK)
+ return BDELTA_MEMORY;
+ }
+
+ for (; *descent != 0; descent++, p = p2) {
+ if (*descent < 0) {
+ /* Descend left. */
+ d++;
+ k--;
+ p2 = p + d;
+ current_op = OP_INSERT;
+ assert(*p2 >= *p);
+ copy_length = *p2 - *p;
+ } else {
+ /* Descend right. */
+ d++;
+ k++;
+ p2 = p + d + 1;
+ current_op = OP_SKIP;
+ assert(*p2 > *p);
+ copy_length = *p2 - *p - 1;
+ }
+
+ if (pending_op == current_op) {
+ pending_length++;
+ } else {
+ if (pending_op != 0) {
+ if (csi32_emit_op(patch_out, pending_op, pending_length, &new_) != BDELTA_OK)
+ return BDELTA_MEMORY;
+ }
+ pending_op = current_op;
+ pending_length = 1;
+ }
+
+ if (copy_length > 0) {
+ if (csi32_emit_op(patch_out, pending_op, pending_length, &new_) != BDELTA_OK)
+ return BDELTA_MEMORY;
+ pending_op = 0;
+ if (csi32_emit_op(patch_out, OP_COPY, copy_length, &new_) != BDELTA_OK)
+ return BDELTA_MEMORY;
+ }
+ }
+ assert(d == triangle->solution_d);
+ assert(k == triangle->solution_k);
+ assert(p == triangle->solution_ptr);
+
+ /* Emit the last pending op, unless it's a skip. */
+ if (pending_op != 0 && pending_op != OP_SKIP) {
+ if (csi32_emit_op(patch_out, pending_op, pending_length, &new_) != BDELTA_OK)
+ return BDELTA_MEMORY;
+ }
+
+ assert(new_ == new_end);
+ return BDELTA_OK;
+}
+
+/*
+ * Generate a patch using Myers' O(ND) algorithm.
+ *
+ * The patch is appended to @patch_out, which must be initialized before calling.
+ *
+ * Return values:
+ *
+ * BDELTA_OK: Success
+ * BDELTA_MEMORY: Memory allocation failed
+ * BDELTA_INTERNAL_INPUTS_TOO_LARGE: Input sizes are too large
+ * BDELTA_INTERNAL_DMAX_EXCEEDED: d_max exceeded (strings are too different)
+ */
+static BDELTAcode diff_myers(
+ const char *old, size_t old_size,
+ const char *new_, size_t new_size,
+ SB *patch_out)
+{
+ Triangle triangle;
+ signed char *descent;
+ BDELTAcode rc;
+
+ /* Make sure old_size + new_size does not overflow int or uint32_t. */
+ if (old_size >= UINT32_MAX ||
+ new_size >= UINT32_MAX - old_size ||
+ old_size >= (unsigned int)INT_MAX ||
+ new_size >= (unsigned int)INT_MAX - old_size)
+ return BDELTA_INTERNAL_INPUTS_TOO_LARGE;
+
+ rc = build_triangle(old, old_size, new_, new_size, 1000, &triangle);
+ if (rc != BDELTA_OK)
+ return rc;
+
+ descent = climb_triangle(&triangle);
+ if (descent == NULL)
+ goto oom1;
+
+ if (descent_to_patch(descent, &triangle, new_, new_size, patch_out) != BDELTA_OK)
+ goto oom2;
+
+ free(descent);
+ free(triangle.data);
+ return BDELTA_OK;
+
+oom2:
+ free(descent);
+oom1:
+ free(triangle.data);
+ return BDELTA_MEMORY;
+}
+
+BDELTAcode bdelta_diff(
+ const void *old, size_t old_size,
+ const void *new_, size_t new_size,
+ void **patch_out, size_t *patch_size_out)
+{
+ SB patch;
+
+ if (sb_init(&patch) != 0)
+ goto out_of_memory;
+
+ if (new_size == 0)
+ goto emit_new_literally;
+
+ if (diff_myers(old, old_size, new_, new_size, &patch) != BDELTA_OK)
+ goto emit_new_literally;
+
+ if (sb_size(&patch) > new_size) {
+ /*
+ * A literal copy of new is no longer than this patch.
+ * All that for nothing.
+ */
+ goto emit_new_literally;
+ }
+
+ /*
+ * Verify that patch, when applied to old, produces the correct text.
+ * If it doesn't, it's a bug, but fall back to a simple emit
+ * to avert data corruption.
+ */
+ {
+ void *result;
+ size_t result_size;
+ BDELTAcode rc;
+ int correct;
+
+ rc = bdelta_patch(
+ old, old_size,
+ patch.start, patch.cur - patch.start,
+ &result, &result_size
+ );
+
+ switch (rc) {
+ case BDELTA_OK:
+ correct = (result_size == new_size &&
+ memcmp(result, new_, new_size) == 0);
+ free(result);
+ break;
+
+ case BDELTA_MEMORY:
+ goto out_of_memory;
+
+ default:
+ correct = 0;
+ break;
+ }
+
+ if (!correct) {
+ assert(0);
+ goto emit_new_literally;
+ }
+ }
+
+ sb_return(&patch, patch_out, patch_size_out);
+ return BDELTA_OK;
+
+emit_new_literally:
+ if (patch.cur != patch.start) {
+ free(patch.start);
+ if (sb_init(&patch) != 0)
+ goto out_of_memory;
+ }
+ if (sb_putc(&patch, PT_LITERAL) != 0 || sb_write(&patch, new_, new_size) != 0)
+ goto out_of_memory;
+ sb_return(&patch, patch_out, patch_size_out);
+ return BDELTA_OK;
+
+out_of_memory:
+ sb_discard(&patch, patch_out, patch_size_out);
+ return BDELTA_MEMORY;
+}
+
+/*
+ * Return values:
+ *
+ * BDELTA_OK: Success
+ * BDELTA_PATCH_INVALID: Patch is malformed
+ * BDELTA_PATCH_MISMATCH: Old string is too small
+ * BDELTA_MEMORY: Memory allocation failed
+ */
+static BDELTAcode patch_csi32(
+ const unsigned char *o, const unsigned char *oe,
+ const unsigned char *p, const unsigned char *pe,
+ SB *new_out)
+{
+ int op;
+ uint32_t size;
+
+ while (csi32_parse_op(&p, pe, &op, &size)) {
+ if ((op == OP_COPY || op == OP_SKIP) && (size_t)(oe - o) < size) {
+ /* Copy or skip instruction exceeds length of old string. */
+ return BDELTA_PATCH_MISMATCH;
+ }
+ if (op == OP_COPY || op == OP_INSERT)
+ sb_need(new_out, size);
+
+ switch (op) {
+ case OP_COPY: /* Copy @size bytes from old string. */
+ memcpy(new_out->cur, o, size);
+ new_out->cur += size;
+ o += size;
+ break;
+
+ case OP_SKIP: /* Skip @size bytes of old string. */
+ o += size;
+ break;
+
+ case OP_INSERT: /* Insert @size new bytes (from the patch script). */
+ memcpy(new_out->cur, p, size);
+ new_out->cur += size;
+ p += size;
+ break;
+
+ default:
+ assert(0);
+ }
+ }
+ if (p != pe)
+ return BDELTA_PATCH_INVALID;
+
+ return BDELTA_OK;
+
+out_of_memory:
+ return BDELTA_MEMORY;
+}
+
+BDELTAcode bdelta_patch(
+ const void *old, size_t old_size,
+ const void *patch, size_t patch_size,
+ void **new_out, size_t *new_size_out)
+{
+ const unsigned char *o = old;
+ const unsigned char *oe = o + old_size;
+ const unsigned char *p = patch;
+ const unsigned char *pe = p + patch_size;
+ SB result;
+ BDELTAcode rc;
+
+ if (sb_init(&result) != 0) {
+ rc = BDELTA_MEMORY;
+ goto discard;
+ }
+
+ if (p >= pe) {
+ rc = BDELTA_PATCH_INVALID;
+ goto discard;
+ }
+
+ switch (*p++) {
+ case PT_LITERAL:
+ if (sb_write(&result, p, pe - p) != 0) {
+ rc = BDELTA_MEMORY;
+ goto discard;
+ }
+ break;
+
+ case PT_CSI32:
+ rc = patch_csi32(o, oe, p, pe, &result);
+ if (rc != BDELTA_OK)
+ goto discard;
+ break;
+
+ default:
+ rc = BDELTA_PATCH_INVALID;
+ goto discard;
+ }
+
+ sb_return(&result, new_out, new_size_out);
+ return BDELTA_OK;
+
+discard:
+ sb_discard(&result, new_out, new_size_out);
+ return rc;
+}
+
+const char *bdelta_strerror(BDELTAcode code)
+{
+ switch (code) {
+ case BDELTA_OK:
+ return "Success";
+ case BDELTA_MEMORY:
+ return "Could not allocate memory";
+ case BDELTA_PATCH_INVALID:
+ return "Patch is invalid";
+ case BDELTA_PATCH_MISMATCH:
+ return "Patch applied to wrong data";
+
+ case BDELTA_INTERNAL_DMAX_EXCEEDED:
+ return "Difference threshold exceeded (internal error)";
+ case BDELTA_INTERNAL_INPUTS_TOO_LARGE:
+ return "Inputs are too large (internal error)";
+
+ default:
+ return "Invalid error code";
+ }
+}
+
+void bdelta_perror(const char *s, BDELTAcode code)
+{
+ if (s != NULL && *s != '\0')
+ fprintf(stderr, "%s: %s\n", s, bdelta_strerror(code));
+ else
+ fprintf(stderr, "%s\n", bdelta_strerror(code));
+}
projects / ccan / blobdiff