+++ /dev/null
-/* diff - compute a shortest edit script (SES) given two sequences
- * Copyright (c) 2004 Michael B. Allen <mba2000 ioplex.com>
- * Copyright (c) 2010-2014, Vsevolod Stakhov
- *
- * The MIT License
- *
- * 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.
- */
-
-/* This algorithm is basically Myers' solution to SES/LCS with
- * the Hirschberg linear space refinement as described in the
- * following publication:
- *
- * E. Myers, ``An O(ND) Difference Algorithm and Its Variations,''
- * Algorithmica 1, 2 (1986), 251-266.
- * http://www.cs.arizona.edu/people/gene/PAPERS/diff.ps
- *
- * This is the same algorithm used by GNU diff(1).
- */
-
-
-#include "config.h"
-#include "diff.h"
-
-
-#define FV(k) _v (ctx, (k), 0)
-#define RV(k) _v (ctx, (k), 1)
-
-#define MAX_DIFF 1024
-
-struct _ctx
-{
- GArray *buf;
- GArray *ses;
- gint si;
- gint dmax;
-};
-
-struct middle_snake
-{
- gint x, y, u, v;
-};
-
-static
-void
-maybe_resize_array (GArray *arr, guint k)
-{
- if (k > arr->len) {
- g_array_set_size (arr, k);
- }
-
-}
-
-static void
-_setv (struct _ctx *ctx, gint k, gint r, gint val)
-{
- gint j;
- gint *i;
- /* Pack -N to N ginto 0 to N * 2
- */
- j = k <= 0 ? -k * 4 + r : k * 4 + (r - 2);
-
- maybe_resize_array (ctx->buf, j);
- i = (gint *) &g_array_index (ctx->buf, gint, j);
- *i = val;
-}
-
-static gint
-_v (struct _ctx *ctx, gint k, gint r)
-{
- gint j;
-
- j = k <= 0 ? -k * 4 + r : k * 4 + (r - 2);
-
- return *((gint *) &g_array_index (ctx->buf, gint, j));
-}
-
-static gint
-_find_middle_snake (const void *a, gint aoff, gint n, const void *b,
- gint boff, gint m, struct _ctx *ctx, struct middle_snake *ms)
-{
- gint delta, odd, mid, d;
-
- delta = n - m;
- odd = delta & 1;
- mid = (n + m) / 2;
- mid += odd;
-
- _setv (ctx, 1, 0, 0);
- _setv (ctx, delta - 1, 1, n);
-
- for (d = 0; d <= mid; d++) {
- gint k, x, y;
-
- if ((2 * d - 1) >= ctx->dmax) {
- return ctx->dmax;
- }
-
- for (k = d; k >= -d; k -= 2) {
- if (k == -d || (k != d && FV (k - 1) < FV (k + 1))) {
- x = FV (k + 1);
- }
- else {
- x = FV (k - 1) + 1;
- }
- y = x - k;
-
- ms->x = x;
- ms->y = y;
- const guchar *a0 = (const guchar *) a + aoff;
- const guchar *b0 = (const guchar *) b + boff;
- while (x < n && y < m && a0[x] == b0[y]) {
- x++;
- y++;
- }
- _setv (ctx, k, 0, x);
-
- if (odd && k >= (delta - (d - 1)) && k <= (delta + (d - 1))) {
- if (x >= RV (k)) {
- ms->u = x;
- ms->v = y;
- return 2 * d - 1;
- }
- }
- }
- for (k = d; k >= -d; k -= 2) {
- gint kr = (n - m) + k;
-
- if (k == d || (k != -d && RV (kr - 1) < RV (kr + 1))) {
- x = RV (kr - 1);
- }
- else {
- x = RV (kr + 1) - 1;
- }
- y = x - kr;
-
- ms->u = x;
- ms->v = y;
- const guchar *a0 = (const guchar *) a + aoff;
- const guchar *b0 = (const guchar *) b + boff;
- while (x > 0 && y > 0 && a0[x - 1] == b0[y - 1]) {
- x--;
- y--;
- }
- _setv (ctx, kr, 1, x);
-
- if (!odd && kr >= -d && kr <= d) {
- if (x <= FV (kr)) {
- ms->x = x;
- ms->y = y;
- return 2 * d;
- }
- }
- }
- }
-
- errno = EFAULT;
-
- return -1;
-}
-
-static void
-_edit (struct _ctx *ctx, gint op, gint off, gint len)
-{
- struct diff_edit *e = NULL, newe;
-
- if (len == 0 || ctx->ses == NULL) {
- return;
- }
- /*
- * Add an edit to the SES (or
- * coalesce if the op is the same)
- */
- if (ctx->ses->len != 0) {
- e = &g_array_index (ctx->ses, struct diff_edit, ctx->ses->len - 1);
- }
- if (e == NULL || e->op != op) {
- newe.op = op;
- newe.off = off;
- newe.len = len;
- g_array_append_val (ctx->ses, newe);
- }
- else {
- e->len += len;
- }
-}
-
-static gint
-_ses (const void *a, gint aoff, gint n, const void *b, gint boff,
- gint m, struct _ctx *ctx)
-{
- struct middle_snake ms = {
- .x = 0,
- .y = 0,
- .u = 0,
- .v = 0
- };
- gint d;
-
- if (n == 0) {
- _edit (ctx, DIFF_INSERT, boff, m);
- d = m;
- }
- else if (m == 0) {
- _edit (ctx, DIFF_DELETE, aoff, n);
- d = n;
- }
- else {
- /* Find the middle "snake" around which we
- * recursively solve the sub-problems.
- */
- d = _find_middle_snake (a, aoff, n, b, boff, m, ctx, &ms);
- if (d == -1) {
- return -1;
- }
- else if (d >= ctx->dmax) {
- return ctx->dmax;
- }
- else if (ctx->ses == NULL) {
- return d;
- }
- else if (d > 1) {
- if (_ses (a, aoff, ms.x, b, boff, ms.y, ctx) == -1) {
- return -1;
- }
-
- _edit (ctx, DIFF_MATCH, aoff + ms.x, ms.u - ms.x);
-
- aoff += ms.u;
- boff += ms.v;
- n -= ms.u;
- m -= ms.v;
- if (_ses (a, aoff, n, b, boff, m, ctx) == -1) {
- return -1;
- }
- }
- else {
- gint x = ms.x;
- gint u = ms.u;
-
- /* There are only 4 base cases when the
- * edit distance is 1.
- *
- * n > m m > n
- *
- * - |
- * \ \ x != u
- * \ \
- *
- * \ \
- * \ \ x == u
- * - |
- */
-
- /*
- * XXX: coverity found this code suspicious, needs checking
- */
- if (m > n) {
- if (x == u) {
- _edit (ctx, DIFF_MATCH, aoff, n);
- _edit (ctx, DIFF_INSERT, boff + (m - 1), 1);
- }
- else {
- _edit (ctx, DIFF_INSERT, boff, 1);
- _edit (ctx, DIFF_MATCH, aoff, n);
- }
- }
- else {
- if (x == u) {
- _edit (ctx, DIFF_MATCH, aoff, m);
- _edit (ctx, DIFF_DELETE, aoff + (n - 1), 1);
- }
- else {
- _edit (ctx, DIFF_DELETE, aoff, 1);
- _edit (ctx, DIFF_MATCH, aoff + 1, m);
- }
- }
- }
- }
-
- return d;
-}
-
-gint
-rspamd_diff (const void *a, gint aoff, gint n, const void *b, gint boff, gint m,
- gint dmax, GArray *ses, gint *sn)
-{
- struct _ctx ctx;
- gint d, x, y;
- GArray *tmp;
-
- tmp = g_array_sized_new (FALSE, TRUE, sizeof(gint), dmax);
- ctx.buf = tmp;
- ctx.ses = ses;
- ctx.si = 0;
- ctx.dmax = dmax;
-
- /* The _ses function assumes the SES will begin or end with a delete
- * or insert. The following will insure this is true by eating any
- * beginning matches. This is also a quick to process sequences
- * that match entirely.
- */
- x = y = 0;
- const guchar *a0 = (const guchar *) a + aoff;
- const guchar *b0 = (const guchar *) b + boff;
- while (x < n && y < m && a0[x] == b0[y]) {
- x++;
- y++;
- }
- _edit (&ctx, DIFF_MATCH, aoff, x);
-
- if ((d = _ses (a, aoff + x, n - x, b, boff + y, m - y, &ctx)) == -1) {
- g_array_free (tmp, TRUE);
- return -1;
- }
-
- g_array_free (tmp, TRUE);
- return d;
-}
-
-static guint32
-compare_diff_distance_unnormalized (rspamd_fstring_t *s1, rspamd_fstring_t *s2)
-{
- GArray *ses;
- struct diff_edit *e;
- guint i;
- guint32 distance = 0;
-
- ses = g_array_sized_new (FALSE, TRUE, sizeof (struct diff_edit), MAX_DIFF);
-
- if (rspamd_diff (s1->begin, 0, s1->len,
- s2->begin, 0, s2->len, MAX_DIFF, ses, NULL) == -1) {
- /* Diff failed, strings are different */
- g_array_free (ses, TRUE);
- return 0;
- }
-
- for (i = 0; i < ses->len; i++) {
- e = &g_array_index (ses, struct diff_edit, i);
- if (e->op != DIFF_MATCH) {
- distance += e->len;
- }
- }
-
- g_array_free (ses, TRUE);
-
- return distance;
-}
-
-guint32
-rspamd_diff_distance (rspamd_fstring_t *s1, rspamd_fstring_t *s2)
-{
-
- return 100 -
- (2 *
- compare_diff_distance_unnormalized (s1,
- s2) * 100) / (s1->len + s2->len);
-}
-
-
-guint32
-rspamd_diff_distance_normalized (rspamd_fstring_t *s1, rspamd_fstring_t *s2)
-{
- gchar b1[BUFSIZ], b2[BUFSIZ], *t, *h, *p1, *p2;
- gsize r1, r2;
- rspamd_fstring_t t1, t2;
- guint32 cur_diff = 0;
-
- r1 = s1->len;
- r2 = s2->len;
- p1 = s1->begin;
- p2 = s2->begin;
-
- while (r1 > 0 && r2 > 0) {
- /* Copy strings to the buffer normalized */
- h = p1;
- t = b1;
-
- /* The first string */
- while (r1 > 0 && t - b1 < (gint)sizeof (b1)) {
- if (!g_ascii_isspace (*h)) {
- *t++ = g_ascii_tolower (*h);
- }
- h++;
- p1++;
- r1--;
- }
-
- t1.begin = b1;
- t1.len = t - b1;
-
- /* The second string */
- h = p2;
- t = b2;
- while (r2 > 0 && t - b2 < (gint)sizeof (b2)) {
- if (!g_ascii_isspace (*h)) {
- *t++ = g_ascii_tolower (*h);
- }
- h++;
- p2++;
- r2--;
- }
-
- t2.begin = b2;
- t2.len = t - b2;
-
- cur_diff += compare_diff_distance_unnormalized (&t1, &t2);
- }
-
- if (r1 > 0) {
- h = p1;
- while (r1 > 0) {
- if (!g_ascii_isspace (*h)) {
- cur_diff++;
- }
- r1--;
- h++;
- }
- }
- else if (r2 > 0) {
- h = p2;
- while (r2 > 0) {
- if (!g_ascii_isspace (*h)) {
- cur_diff++;
- }
- r2--;
- h++;
- }
- }
-
- return 100 - (2 * cur_diff * 100) / (s1->len + s2->len);
-}
+++ /dev/null
-/* Copyright (c) 2010, Vsevolod Stakhov
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- * * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * * Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED ''AS IS'' AND ANY
- * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
- * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL Rambler BE LIABLE FOR ANY
- * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
- * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
- * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-
-#ifndef DIFF_H_
-#define DIFF_H_
-
-#include "config.h"
-#include "fstring.h"
-
-typedef enum
-{
- DIFF_MATCH = 1,
- DIFF_DELETE,
- DIFF_INSERT
-} diff_op;
-
-struct diff_edit
-{
- gshort op;
- gint off; /* off ginto s1 if MATCH or DELETE but s2 if INSERT */
- gint len;
-};
-
-/*
- * Calculate difference between two strings using diff algorithm
- * @param a the first line begin
- * @param aoff the first line offset
- * @param n the first line length
- * @param b the second line begin
- * @param boff the second line offset
- * @param b the second line length
- * @param dmax maximum differences number
- * @param ses here would be stored the shortest script to transform a to b
- * @param sn here would be stored a number of differences between a and b
- * @return distance between strings or -1 in case of error
- */
-gint rspamd_diff (const void *a,
- gint aoff,
- gint n,
- const void *b,
- gint boff,
- gint m,
- gint dmax,
- GArray *ses,
- gint *sn);
-
-/*
- * Calculate distance between two strings (in percentage) using diff algorithm.
- * @return 100 in case of identical strings and 0 in case of totally different strings.
- */
-guint32 rspamd_diff_distance (rspamd_fstring_t *s1, rspamd_fstring_t *s2);
-
-/*
- * Calculate distance between two strings (in percentage) using diff algorithm. Strings are normalized before:
- * all spaces are removed and all characters are lowercased.
- * @return 100 in case of identical strings and 0 in case of totally different strings.
- */
-guint32 rspamd_diff_distance_normalized (rspamd_fstring_t *s1, rspamd_fstring_t *s2);
-
-#endif /* DIFF_H_ */
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