1 /* _PDCLIB_allocpages( int const )
3 This file is part of the Public Domain C Library (PDCLib).
4 Permission is granted to use, modify, and / or redistribute at will.
7 /* This is an example implementation of _PDCLIB_allocpages() (declared in
8 _PDCLIB_config.h), fit for use with POSIX kernels.
14 void * sbrk( intptr_t );
16 #include <_PDCLIB_glue.h>
18 static void * membreak = NULL;
20 void * _PDCLIB_allocpages( int const n )
22 if ( membreak == NULL )
24 /* first call, make sure end-of-heap is page-aligned */
25 intptr_t unaligned = 0;
27 unaligned = _PDCLIB_PAGESIZE - (intptr_t)membreak % _PDCLIB_PAGESIZE;
28 if ( unaligned < _PDCLIB_PAGESIZE )
30 /* end-of-heap not page-aligned - adjust */
31 if ( sbrk( unaligned ) != membreak )
36 membreak = (char *)membreak + unaligned;
39 /* increasing or decreasing heap - standard operation */
40 void * oldbreak = membreak;
41 membreak = (void *)( (char *)membreak + ( n * _PDCLIB_PAGESIZE ) );
42 if ( sbrk( (char*)membreak - (char*)oldbreak ) == membreak )
56 #include <_PDCLIB_test.h>
60 char * startbreak = sbrk( 0 );
61 TESTCASE( _PDCLIB_allocpages( 0 ) );
62 TESTCASE( ( (char *)sbrk( 0 ) - startbreak ) <= _PDCLIB_PAGESIZE );
63 startbreak = sbrk( 0 );
64 TESTCASE( _PDCLIB_allocpages( 1 ) );
65 TESTCASE( sbrk( 0 ) == startbreak + ( 1 * _PDCLIB_PAGESIZE ) );
66 TESTCASE( _PDCLIB_allocpages( 5 ) );
67 TESTCASE( sbrk( 0 ) == startbreak + ( 6 * _PDCLIB_PAGESIZE ) );
68 TESTCASE( _PDCLIB_allocpages( -3 ) );
69 TESTCASE( sbrk( 0 ) == startbreak + ( 3 * _PDCLIB_PAGESIZE ) );