umf_mem_alloc_head_block.c
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/* ========================================================================== */
/* === UMF_mem_alloc_head_block ============================================= */
/* ========================================================================== */
/* -------------------------------------------------------------------------- */
/* UMFPACK Copyright (c) Timothy A. Davis, CISE, */
/* Univ. of Florida. All Rights Reserved. See ../Doc/License for License. */
/* web: http://www.cise.ufl.edu/research/sparse/umfpack */
/* -------------------------------------------------------------------------- */
/* The UMF_mem_* routines manage the Numeric->Memory memory space. */
/* allocate nunits from head of Numeric->Memory. No header allocated. */
/* Returns the index into Numeric->Memory if successful, or 0 on failure. */
#include "umf_internal.h"
GLOBAL Int UMF_mem_alloc_head_block
(
NumericType *Numeric,
Int nunits
)
{
Int p, usage ;
DEBUG2 (("GET BLOCK: from head, size "ID" ", nunits)) ;
ASSERT (Numeric != (NumericType *) NULL) ;
ASSERT (Numeric->Memory != (Unit *) NULL) ;
#ifndef NDEBUG
if (UMF_allocfail)
{
/* pretend to fail, to test garbage_collection */
DEBUGm2 (("UMF_mem_alloc_head_block: pretend to fail\n")) ;
UMF_allocfail = FALSE ; /* don't fail the next time */
return (0) ;
}
#endif
if (nunits > (Numeric->itail - Numeric->ihead))
{
DEBUG2 ((" failed\n")) ;
return (0) ;
}
/* return p as an offset from Numeric->Memory */
p = Numeric->ihead ;
Numeric->ihead += nunits ;
DEBUG2 (("p: "ID"\n", p)) ;
usage = Numeric->ihead + Numeric->tail_usage ;
Numeric->max_usage = MAX (Numeric->max_usage, usage) ;
return (p) ;
}