70 lines
2.2 KiB
C
70 lines
2.2 KiB
C
/****************************************************************
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* *
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* Copyright 2001, 2011 Fidelity Information Services, Inc *
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* *
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* This source code contains the intellectual property *
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* of its copyright holder(s), and is made available *
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* under a license. If you do not know the terms of *
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* the license, please stop and do not read further. *
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* *
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****************************************************************/
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#include "mdef.h"
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#include "gtm_string.h"
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#include "mmemory.h"
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#include "min_max.h"
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GBLREF int mcavail;
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GBLREF mcalloc_hdr *mcavailptr, *mcavailbase;
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char *mcalloc(unsigned int n)
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{
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mcalloc_hdr *hdr, *nxt, *ptr;
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int new_size, rel_size;
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/* Choice of char_ptr_t made because it is a 64 bit pointer on Tru64 which
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* is the alignment we need there, or any other 64 bit platforms we support
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* in the future.
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*/
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n = ROUND_UP2(n, SIZEOF(char_ptr_t));
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if (n > mcavail)
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{ /* No sufficient space in the current block. Follow the link and check if the next block has sufficient
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* space. There is no next block or the next one doesn't have enough space, allocate a new block with
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* the requested size and insert it after the current block.
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*/
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hdr = mcavailptr->link;
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if (NULL == hdr || n > hdr->size)
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{
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if (NULL != hdr)
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{ /* i.e. the next block doesn't have sufficient space for n. Release as many small blocks as
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* necessary to make up for the space that we are allocating for the large block.
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* By release several small blocks and replacing them with a large block ensures that total
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* memory footprint is not increased due to a rare occurence of large routine compilation.
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*/
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rel_size = 0;
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for (nxt = hdr; NULL != nxt && (rel_size += nxt->size) < n; nxt = ptr)
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{
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ptr = nxt->link;
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free(nxt);
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}
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} else
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nxt = NULL;
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new_size = (int)MAX(MC_DSBLKSIZE, (n + MCALLOC_HDR_SZ));
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hdr = (mcalloc_hdr *)malloc(new_size);
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hdr->link = nxt;
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hdr->size = (int4)(new_size - MCALLOC_HDR_SZ);
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mcavailptr->link = hdr;
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}
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assert(n <= hdr->size);
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memset(&hdr->data[0], 0, hdr->size);
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mcavailptr = hdr;
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mcavail = hdr->size;
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}
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mcavail -= n;
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assert(mcavail >= 0);
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return &mcavailptr->data[mcavail];
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}
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