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![Linus Torvalds](/assets/img/avatar_default.png)
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>
55 lines
1.9 KiB
C
55 lines
1.9 KiB
C
/*
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* LibXDiff by Davide Libenzi ( File Differential Library )
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* Copyright (C) 2003 Davide Libenzi
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Davide Libenzi <davidel@xmailserver.org>
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*
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*/
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#if !defined(XMACROS_H)
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#define XMACROS_H
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#define XDL_MIN(a, b) ((a) < (b) ? (a): (b))
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#define XDL_MAX(a, b) ((a) > (b) ? (a): (b))
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#define XDL_ABS(v) ((v) >= 0 ? (v): -(v))
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#define XDL_ISDIGIT(c) ((c) >= '0' && (c) <= '9')
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#define XDL_ADDBITS(v,b) ((v) + ((v) >> (b)))
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#define XDL_MASKBITS(b) ((1UL << (b)) - 1)
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#define XDL_HASHLONG(v,b) (XDL_ADDBITS((unsigned long)(v), b) & XDL_MASKBITS(b))
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#define XDL_PTRFREE(p) do { if (p) { xdl_free(p); (p) = NULL; } } while (0)
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#define XDL_LE32_PUT(p, v) \
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do { \
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unsigned char *__p = (unsigned char *) (p); \
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*__p++ = (unsigned char) (v); \
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*__p++ = (unsigned char) ((v) >> 8); \
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*__p++ = (unsigned char) ((v) >> 16); \
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*__p = (unsigned char) ((v) >> 24); \
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} while (0)
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#define XDL_LE32_GET(p, v) \
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do { \
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unsigned char const *__p = (unsigned char const *) (p); \
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(v) = (unsigned long) __p[0] | ((unsigned long) __p[1]) << 8 | \
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((unsigned long) __p[2]) << 16 | ((unsigned long) __p[3]) << 24; \
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} while (0)
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#endif /* #if !defined(XMACROS_H) */
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