f7b587bf65
Add a helper to grow an array. This is analogous to ALLOC_GROW() in the rest of the codebase but returns −1 on allocation failure to accommodate other users of libxdiff such as libgit2. It will also return a error if the multiplication overflows while calculating the new allocation size. Note that this keeps doubling on reallocation like the code it is replacing rather than increasing the existing size by half like ALLOC_GROW(). It does however copy ALLOC_GROW()'s trick of adding a small amount to the new allocation to avoid a lot of reallocations at small sizes. Note that xdl_alloc_grow_helper() uses long rather than size_t for `nr` and `alloc` to match the existing code. Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
72 lines
2.5 KiB
C
72 lines
2.5 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, see
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* <http://www.gnu.org/licenses/>.
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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_ISSPACE(c) (isspace((unsigned char)(c)))
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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_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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/* Allocate an array of nr elements, returns NULL on failure */
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#define XDL_ALLOC_ARRAY(p, nr) \
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((p) = SIZE_MAX / sizeof(*(p)) >= (size_t)(nr) \
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? xdl_malloc((nr) * sizeof(*(p))) \
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: NULL)
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/* Allocate an array of nr zeroed out elements, returns NULL on failure */
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#define XDL_CALLOC_ARRAY(p, nr) ((p) = xdl_calloc(nr, sizeof(*(p))))
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/*
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* Ensure array p can accommodate at least nr elements, growing the
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* array and updating alloc (which is the number of allocated
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* elements) as necessary. Frees p and returns -1 on failure, returns
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* 0 on success
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*/
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#define XDL_ALLOC_GROW(p, nr, alloc) \
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(-!((nr) <= (alloc) || \
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((p) = xdl_alloc_grow_helper((p), (nr), &(alloc), sizeof(*(p))))))
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#endif /* #if !defined(XMACROS_H) */
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