mirror of
https://github.com/git/git.git
synced 2024-10-30 22:07:53 +01:00
307ab20b33
Because the default Myers, patience and histogram algorithms cannot be in effect at the same time, XDL_PATIENCE_DIFF and XDL_HISTOGRAM_DIFF are not independent bits. Instead of wasting one bit per algorithm, define a few macros to access the few bits they occupy and update the code that access them. Signed-off-by: Junio C Hamano <gitster@pobox.com>
363 lines
9 KiB
C
363 lines
9 KiB
C
/*
|
|
* Copyright (C) 2010, Google Inc.
|
|
* and other copyright owners as documented in JGit's IP log.
|
|
*
|
|
* This program and the accompanying materials are made available
|
|
* under the terms of the Eclipse Distribution License v1.0 which
|
|
* accompanies this distribution, is reproduced below, and is
|
|
* available at http://www.eclipse.org/org/documents/edl-v10.php
|
|
*
|
|
* 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.
|
|
*
|
|
* - Neither the name of the Eclipse Foundation, Inc. nor the
|
|
* names of its contributors may be used to endorse or promote
|
|
* products derived from this software without specific prior
|
|
* written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
|
|
* CONTRIBUTORS "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 THE COPYRIGHT OWNER OR
|
|
* CONTRIBUTORS 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.
|
|
*/
|
|
|
|
#include "xinclude.h"
|
|
#include "xtypes.h"
|
|
#include "xdiff.h"
|
|
|
|
#define MAX_PTR UINT_MAX
|
|
#define MAX_CNT UINT_MAX
|
|
|
|
#define LINE_END(n) (line##n + count##n - 1)
|
|
#define LINE_END_PTR(n) (*line##n + *count##n - 1)
|
|
|
|
struct histindex {
|
|
struct record {
|
|
unsigned int ptr, cnt;
|
|
struct record *next;
|
|
} **records, /* an ocurrence */
|
|
**line_map; /* map of line to record chain */
|
|
chastore_t rcha;
|
|
unsigned int *next_ptrs;
|
|
unsigned int table_bits,
|
|
records_size,
|
|
line_map_size;
|
|
|
|
unsigned int max_chain_length,
|
|
key_shift,
|
|
ptr_shift;
|
|
|
|
unsigned int cnt,
|
|
has_common;
|
|
|
|
xdfenv_t *env;
|
|
xpparam_t const *xpp;
|
|
};
|
|
|
|
struct region {
|
|
unsigned int begin1, end1;
|
|
unsigned int begin2, end2;
|
|
};
|
|
|
|
#define LINE_MAP(i, a) (i->line_map[(a) - i->ptr_shift])
|
|
|
|
#define NEXT_PTR(index, ptr) \
|
|
(index->next_ptrs[(ptr) - index->ptr_shift])
|
|
|
|
#define CNT(index, ptr) \
|
|
((LINE_MAP(index, ptr))->cnt)
|
|
|
|
#define REC(env, s, l) \
|
|
(env->xdf##s.recs[l - 1])
|
|
|
|
static int cmp_recs(xpparam_t const *xpp,
|
|
xrecord_t *r1, xrecord_t *r2)
|
|
{
|
|
return r1->ha == r2->ha &&
|
|
xdl_recmatch(r1->ptr, r1->size, r2->ptr, r2->size,
|
|
xpp->flags);
|
|
}
|
|
|
|
#define CMP_ENV(xpp, env, s1, l1, s2, l2) \
|
|
(cmp_recs(xpp, REC(env, s1, l1), REC(env, s2, l2)))
|
|
|
|
#define CMP(i, s1, l1, s2, l2) \
|
|
(cmp_recs(i->xpp, REC(i->env, s1, l1), REC(i->env, s2, l2)))
|
|
|
|
#define TABLE_HASH(index, side, line) \
|
|
XDL_HASHLONG((REC(index->env, side, line))->ha, index->table_bits)
|
|
|
|
static int scanA(struct histindex *index, int line1, int count1)
|
|
{
|
|
unsigned int ptr, tbl_idx;
|
|
unsigned int chain_len;
|
|
struct record **rec_chain, *rec;
|
|
|
|
for (ptr = LINE_END(1); line1 <= ptr; ptr--) {
|
|
tbl_idx = TABLE_HASH(index, 1, ptr);
|
|
rec_chain = index->records + tbl_idx;
|
|
rec = *rec_chain;
|
|
|
|
chain_len = 0;
|
|
while (rec) {
|
|
if (CMP(index, 1, rec->ptr, 1, ptr)) {
|
|
/*
|
|
* ptr is identical to another element. Insert
|
|
* it onto the front of the existing element
|
|
* chain.
|
|
*/
|
|
NEXT_PTR(index, ptr) = rec->ptr;
|
|
rec->ptr = ptr;
|
|
/* cap rec->cnt at MAX_CNT */
|
|
rec->cnt = XDL_MIN(MAX_CNT, rec->cnt + 1);
|
|
LINE_MAP(index, ptr) = rec;
|
|
goto continue_scan;
|
|
}
|
|
|
|
rec = rec->next;
|
|
chain_len++;
|
|
}
|
|
|
|
if (chain_len == index->max_chain_length)
|
|
return -1;
|
|
|
|
/*
|
|
* This is the first time we have ever seen this particular
|
|
* element in the sequence. Construct a new chain for it.
|
|
*/
|
|
if (!(rec = xdl_cha_alloc(&index->rcha)))
|
|
return -1;
|
|
rec->ptr = ptr;
|
|
rec->cnt = 1;
|
|
rec->next = *rec_chain;
|
|
*rec_chain = rec;
|
|
LINE_MAP(index, ptr) = rec;
|
|
|
|
continue_scan:
|
|
; /* no op */
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int try_lcs(struct histindex *index, struct region *lcs, int b_ptr,
|
|
int line1, int count1, int line2, int count2)
|
|
{
|
|
unsigned int b_next = b_ptr + 1;
|
|
struct record *rec = index->records[TABLE_HASH(index, 2, b_ptr)];
|
|
unsigned int as, ae, bs, be, np, rc;
|
|
int should_break;
|
|
|
|
for (; rec; rec = rec->next) {
|
|
if (rec->cnt > index->cnt) {
|
|
if (!index->has_common)
|
|
index->has_common = CMP(index, 1, rec->ptr, 2, b_ptr);
|
|
continue;
|
|
}
|
|
|
|
as = rec->ptr;
|
|
if (!CMP(index, 1, as, 2, b_ptr))
|
|
continue;
|
|
|
|
index->has_common = 1;
|
|
for (;;) {
|
|
should_break = 0;
|
|
np = NEXT_PTR(index, as);
|
|
bs = b_ptr;
|
|
ae = as;
|
|
be = bs;
|
|
rc = rec->cnt;
|
|
|
|
while (line1 < as && line2 < bs
|
|
&& CMP(index, 1, as - 1, 2, bs - 1)) {
|
|
as--;
|
|
bs--;
|
|
if (1 < rc)
|
|
rc = XDL_MIN(rc, CNT(index, as));
|
|
}
|
|
while (ae < LINE_END(1) && be < LINE_END(2)
|
|
&& CMP(index, 1, ae + 1, 2, be + 1)) {
|
|
ae++;
|
|
be++;
|
|
if (1 < rc)
|
|
rc = XDL_MIN(rc, CNT(index, ae));
|
|
}
|
|
|
|
if (b_next <= be)
|
|
b_next = be + 1;
|
|
if (lcs->end1 - lcs->begin1 < ae - as || rc < index->cnt) {
|
|
lcs->begin1 = as;
|
|
lcs->begin2 = bs;
|
|
lcs->end1 = ae;
|
|
lcs->end2 = be;
|
|
index->cnt = rc;
|
|
}
|
|
|
|
if (np == 0)
|
|
break;
|
|
|
|
while (np <= ae) {
|
|
np = NEXT_PTR(index, np);
|
|
if (np == 0) {
|
|
should_break = 1;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (should_break)
|
|
break;
|
|
|
|
as = np;
|
|
}
|
|
}
|
|
return b_next;
|
|
}
|
|
|
|
static int find_lcs(struct histindex *index, struct region *lcs,
|
|
int line1, int count1, int line2, int count2) {
|
|
int b_ptr;
|
|
|
|
if (scanA(index, line1, count1))
|
|
return -1;
|
|
|
|
index->cnt = index->max_chain_length + 1;
|
|
|
|
for (b_ptr = line2; b_ptr <= LINE_END(2); )
|
|
b_ptr = try_lcs(index, lcs, b_ptr, line1, count1, line2, count2);
|
|
|
|
return index->has_common && index->max_chain_length < index->cnt;
|
|
}
|
|
|
|
static int fall_back_to_classic_diff(struct histindex *index,
|
|
int line1, int count1, int line2, int count2)
|
|
{
|
|
xpparam_t xpp;
|
|
xpp.flags = index->xpp->flags & ~XDF_DIFF_ALGORITHM_MASK;
|
|
|
|
return xdl_fall_back_diff(index->env, &xpp,
|
|
line1, count1, line2, count2);
|
|
}
|
|
|
|
static int histogram_diff(xpparam_t const *xpp, xdfenv_t *env,
|
|
int line1, int count1, int line2, int count2)
|
|
{
|
|
struct histindex index;
|
|
struct region lcs;
|
|
int sz;
|
|
int result = -1;
|
|
|
|
if (count1 <= 0 && count2 <= 0)
|
|
return 0;
|
|
|
|
if (LINE_END(1) >= MAX_PTR)
|
|
return -1;
|
|
|
|
if (!count1) {
|
|
while(count2--)
|
|
env->xdf2.rchg[line2++ - 1] = 1;
|
|
return 0;
|
|
} else if (!count2) {
|
|
while(count1--)
|
|
env->xdf1.rchg[line1++ - 1] = 1;
|
|
return 0;
|
|
}
|
|
|
|
memset(&index, 0, sizeof(index));
|
|
|
|
index.env = env;
|
|
index.xpp = xpp;
|
|
|
|
index.records = NULL;
|
|
index.line_map = NULL;
|
|
/* in case of early xdl_cha_free() */
|
|
index.rcha.head = NULL;
|
|
|
|
index.table_bits = xdl_hashbits(count1);
|
|
sz = index.records_size = 1 << index.table_bits;
|
|
sz *= sizeof(struct record *);
|
|
if (!(index.records = (struct record **) xdl_malloc(sz)))
|
|
goto cleanup;
|
|
memset(index.records, 0, sz);
|
|
|
|
sz = index.line_map_size = count1;
|
|
sz *= sizeof(struct record *);
|
|
if (!(index.line_map = (struct record **) xdl_malloc(sz)))
|
|
goto cleanup;
|
|
memset(index.line_map, 0, sz);
|
|
|
|
sz = index.line_map_size;
|
|
sz *= sizeof(unsigned int);
|
|
if (!(index.next_ptrs = (unsigned int *) xdl_malloc(sz)))
|
|
goto cleanup;
|
|
memset(index.next_ptrs, 0, sz);
|
|
|
|
/* lines / 4 + 1 comes from xprepare.c:xdl_prepare_ctx() */
|
|
if (xdl_cha_init(&index.rcha, sizeof(struct record), count1 / 4 + 1) < 0)
|
|
goto cleanup;
|
|
|
|
index.ptr_shift = line1;
|
|
index.max_chain_length = 64;
|
|
|
|
memset(&lcs, 0, sizeof(lcs));
|
|
if (find_lcs(&index, &lcs, line1, count1, line2, count2))
|
|
result = fall_back_to_classic_diff(&index, line1, count1, line2, count2);
|
|
else {
|
|
if (lcs.begin1 == 0 && lcs.begin2 == 0) {
|
|
while (count1--)
|
|
env->xdf1.rchg[line1++ - 1] = 1;
|
|
while (count2--)
|
|
env->xdf2.rchg[line2++ - 1] = 1;
|
|
result = 0;
|
|
} else {
|
|
result = histogram_diff(xpp, env,
|
|
line1, lcs.begin1 - line1,
|
|
line2, lcs.begin2 - line2);
|
|
if (result)
|
|
goto cleanup;
|
|
result = histogram_diff(xpp, env,
|
|
lcs.end1 + 1, LINE_END(1) - lcs.end1,
|
|
lcs.end2 + 1, LINE_END(2) - lcs.end2);
|
|
if (result)
|
|
goto cleanup;
|
|
}
|
|
}
|
|
|
|
cleanup:
|
|
xdl_free(index.records);
|
|
xdl_free(index.line_map);
|
|
xdl_free(index.next_ptrs);
|
|
xdl_cha_free(&index.rcha);
|
|
|
|
return result;
|
|
}
|
|
|
|
int xdl_do_histogram_diff(mmfile_t *file1, mmfile_t *file2,
|
|
xpparam_t const *xpp, xdfenv_t *env)
|
|
{
|
|
if (xdl_prepare_env(file1, file2, xpp, env) < 0)
|
|
return -1;
|
|
|
|
return histogram_diff(xpp, env,
|
|
env->xdf1.dstart + 1, env->xdf1.dend - env->xdf1.dstart + 1,
|
|
env->xdf2.dstart + 1, env->xdf2.dend - env->xdf2.dstart + 1);
|
|
}
|