5 /* _PDCLIB_allocpages( int const )
7 This file is part of the Public Domain C Library (PDCLib).
8 Permission is granted to use, modify, and / or redistribute at will.
11 /* This is an example implementation of _PDCLIB_allocpages() (declared in
12 _PDCLIB_config.h), fit for use with POSIX kernels.
19 void * sbrk( intptr_t );
21 #ifndef _PDCLIB_GLUE_H
22 #define _PDCLIB_GLUE_H _PDCLIB_GLUE_H
23 #include <_PDCLIB_glue.h>
26 static void * membreak = NULL;
28 void * _PDCLIB_allocpages( int const n )
30 if ( membreak == NULL )
32 /* first call, make sure end-of-heap is page-aligned */
33 intptr_t unaligned = 0;
35 unaligned = _PDCLIB_PAGESIZE - (intptr_t)membreak % _PDCLIB_PAGESIZE;
36 if ( unaligned < _PDCLIB_PAGESIZE )
38 /* end-of-heap not page-aligned - adjust */
39 if ( sbrk( unaligned ) != membreak )
44 membreak = (char *)membreak + unaligned;
47 /* increasing or decreasing heap - standard operation */
48 void * oldbreak = membreak;
49 membreak = (void *)( (char *)membreak + ( n * _PDCLIB_PAGESIZE ) );
50 if ( brk( membreak ) == 0 )
64 #include <_PDCLIB_test.h>
70 char * startbreak = sbrk( 0 );
71 TESTCASE( _PDCLIB_allocpages( 0 ) );
72 TESTCASE( ( (char *)sbrk( 0 ) - startbreak ) <= _PDCLIB_PAGESIZE );
73 startbreak = sbrk( 0 );
74 TESTCASE( _PDCLIB_allocpages( 1 ) );
75 TESTCASE( sbrk( 0 ) == startbreak + ( 1 * _PDCLIB_PAGESIZE ) );
76 TESTCASE( _PDCLIB_allocpages( 5 ) );
77 TESTCASE( sbrk( 0 ) == startbreak + ( 6 * _PDCLIB_PAGESIZE ) );
78 TESTCASE( _PDCLIB_allocpages( -3 ) );
79 TESTCASE( sbrk( 0 ) == startbreak + ( 3 * _PDCLIB_PAGESIZE ) );