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Revision 9de0834663f28bee9e6b2c4647ed6128241ed26f authored by Linus Torvalds on 17 October 2006, 02:58:54 UTC, committed by Junio C Hamano on 17 October 2006, 04:27:44 UTC
Jim Mayering noticed that xdiff library took insanely long time when comparing files with many identical lines. This was because the hash function used in the library is broken on 64-bit architectures and caused too many collisions. http://thread.gmane.org/gmane.comp.version-control.git/28962/focus=28994 Acked-by: Davide Libenzi <davidel@xmaliserver.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
1 parent 6fe5b7f
Tip revision: 9de0834663f28bee9e6b2c4647ed6128241ed26f authored by Linus Torvalds on 17 October 2006, 02:58:54 UTC
Fix hash function in xdiff library
Fix hash function in xdiff library
Tip revision: 9de0834
diffcore.h
/*
* Copyright (C) 2005 Junio C Hamano
*/
#ifndef _DIFFCORE_H_
#define _DIFFCORE_H_
/* This header file is internal between diff.c and its diff transformers
* (e.g. diffcore-rename, diffcore-pickaxe). Never include this header
* in anything else.
*/
/* We internally use unsigned short as the score value,
* and rely on an int capable to hold 32-bits. -B can take
* -Bmerge_score/break_score format and the two scores are
* passed around in one int (high 16-bit for merge and low 16-bit
* for break).
*/
#define MAX_SCORE 60000.0
#define DEFAULT_RENAME_SCORE 30000 /* rename/copy similarity minimum (50%) */
#define DEFAULT_BREAK_SCORE 30000 /* minimum for break to happen (50%) */
#define DEFAULT_MERGE_SCORE 36000 /* maximum for break-merge to happen 60%) */
#define MINIMUM_BREAK_SIZE 400 /* do not break a file smaller than this */
struct diff_filespec {
unsigned char sha1[20];
char *path;
void *data;
void *cnt_data;
unsigned long size;
int xfrm_flags; /* for use by the xfrm */
unsigned short mode; /* file mode */
unsigned sha1_valid : 1; /* if true, use sha1 and trust mode;
* if false, use the name and read from
* the filesystem.
*/
#define DIFF_FILE_VALID(spec) (((spec)->mode) != 0)
unsigned should_free : 1; /* data should be free()'ed */
unsigned should_munmap : 1; /* data should be munmap()'ed */
};
extern struct diff_filespec *alloc_filespec(const char *);
extern void fill_filespec(struct diff_filespec *, const unsigned char *,
unsigned short);
extern int diff_populate_filespec(struct diff_filespec *, int);
extern void diff_free_filespec_data(struct diff_filespec *);
struct diff_filepair {
struct diff_filespec *one;
struct diff_filespec *two;
unsigned short int score;
char status; /* M C R N D U (see Documentation/diff-format.txt) */
unsigned source_stays : 1; /* all of R/C are copies */
unsigned broken_pair : 1;
unsigned renamed_pair : 1;
};
#define DIFF_PAIR_UNMERGED(p) \
(!DIFF_FILE_VALID((p)->one) && !DIFF_FILE_VALID((p)->two))
#define DIFF_PAIR_RENAME(p) ((p)->renamed_pair)
#define DIFF_PAIR_BROKEN(p) \
( (!DIFF_FILE_VALID((p)->one) != !DIFF_FILE_VALID((p)->two)) && \
((p)->broken_pair != 0) )
#define DIFF_PAIR_TYPE_CHANGED(p) \
((S_IFMT & (p)->one->mode) != (S_IFMT & (p)->two->mode))
#define DIFF_PAIR_MODE_CHANGED(p) ((p)->one->mode != (p)->two->mode)
extern void diff_free_filepair(struct diff_filepair *);
extern int diff_unmodified_pair(struct diff_filepair *);
struct diff_queue_struct {
struct diff_filepair **queue;
int alloc;
int nr;
};
extern struct diff_queue_struct diff_queued_diff;
extern struct diff_filepair *diff_queue(struct diff_queue_struct *,
struct diff_filespec *,
struct diff_filespec *);
extern void diff_q(struct diff_queue_struct *, struct diff_filepair *);
extern void diffcore_pathspec(const char **pathspec);
extern void diffcore_break(int);
extern void diffcore_rename(struct diff_options *);
extern void diffcore_merge_broken(void);
extern void diffcore_pickaxe(const char *needle, int opts);
extern void diffcore_order(const char *orderfile);
#define DIFF_DEBUG 0
#if DIFF_DEBUG
void diff_debug_filespec(struct diff_filespec *, int, const char *);
void diff_debug_filepair(const struct diff_filepair *, int);
void diff_debug_queue(const char *, struct diff_queue_struct *);
#else
#define diff_debug_filespec(a,b,c) do {} while(0)
#define diff_debug_filepair(a,b) do {} while(0)
#define diff_debug_queue(a,b) do {} while(0)
#endif
extern int diffcore_count_changes(void *src, unsigned long src_size,
void *dst, unsigned long dst_size,
void **src_count_p,
void **dst_count_p,
unsigned long delta_limit,
unsigned long *src_copied,
unsigned long *literal_added);
#endif
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