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[/] [or1k/] [trunk/] [linux/] [uClibc/] [libc/] [stdlib/] [malloc-standard/] [calloc.c] - Blame information for rev 1771

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Line No. Rev Author Line
1 1325 phoenix
/*
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  This is a version (aka dlmalloc) of malloc/free/realloc written by
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  Doug Lea and released to the public domain.  Use, modify, and
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  redistribute this code without permission or acknowledgement in any
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  way you wish.  Send questions, comments, complaints, performance
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  data, etc to dl@cs.oswego.edu
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  VERSION 2.7.2 Sat Aug 17 09:07:30 2002  Doug Lea  (dl at gee)
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  Note: There may be an updated version of this malloc obtainable at
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           ftp://gee.cs.oswego.edu/pub/misc/malloc.c
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  Check before installing!
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  Hacked up for uClibc by Erik Andersen <andersen@codepoet.org>
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*/
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#include "malloc.h"
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/* ------------------------------ calloc ------------------------------ */
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void* calloc(size_t n_elements, size_t elem_size)
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{
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    mchunkptr p;
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    unsigned long  clearsize;
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    unsigned long  nclears;
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    size_t size, *d;
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    void* mem;
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    /* guard vs integer overflow, but allow nmemb
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     * to fall through and call malloc(0) */
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    size = n_elements * elem_size;
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    if (n_elements && elem_size != (size / n_elements)) {
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        __set_errno(ENOMEM);
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        return NULL;
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    }
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    LOCK;
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    mem = malloc(size);
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    if (mem != 0) {
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        p = mem2chunk(mem);
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        if (!chunk_is_mmapped(p))
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        {
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            /*
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               Unroll clear of <= 36 bytes (72 if 8byte sizes)
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               We know that contents have an odd number of
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               size_t-sized words; minimally 3.
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               */
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            d = (size_t*)mem;
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            clearsize = chunksize(p) - (sizeof(size_t));
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            nclears = clearsize / sizeof(size_t);
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            assert(nclears >= 3);
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            if (nclears > 9)
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                memset(d, 0, clearsize);
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            else {
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                *(d+0) = 0;
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                *(d+1) = 0;
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                *(d+2) = 0;
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                if (nclears > 4) {
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                    *(d+3) = 0;
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                    *(d+4) = 0;
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                    if (nclears > 6) {
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                        *(d+5) = 0;
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                        *(d+6) = 0;
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                        if (nclears > 8) {
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                            *(d+7) = 0;
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                            *(d+8) = 0;
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                        }
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                    }
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                }
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            }
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        }
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#if 0
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        else
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        {
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        /* Standard unix mmap using /dev/zero clears memory so calloc
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         * doesn't need to actually zero anything....
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         */
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            d = (size_t*)mem;
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            /* Note the additional (sizeof(size_t)) */
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            clearsize = chunksize(p) - 2*(sizeof(size_t));
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            memset(d, 0, clearsize);
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        }
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#endif
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    }
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    UNLOCK;
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    return mem;
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}
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