/usr/include/ITK-4.5/vnl/vnl_alloc.h is in libinsighttoolkit4-dev 4.5.0-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 | // This is core/vnl/vnl_alloc.h
#ifndef vnl_alloc_h_
#define vnl_alloc_h_
#ifdef VCL_NEEDS_PRAGMA_INTERFACE
#pragma interface
#endif
//:
// \file
// \author unknown
//
// \brief Default node allocator.
//
// With a reasonable compiler, this should be roughly as fast as the
// original STL class-specific allocators, but with less fragmentation.
// Default_alloc_template parameters are experimental and MAY
// DISAPPEAR in the future. Clients should just use vcl_alloc for now.
//
// Important implementation properties:
// - If the client request an object of size > __MAX_BYTES, the resulting
// object will be obtained directly from malloc.
// - In all other cases, we allocate an object of size exactly
// ROUND_UP(requested_size). Thus the client has enough size
// information that we can return the object to the proper free li*st
// without permanently losing part of the object.
//
// The first template parameter specifies whether more than one thread
// may use this allocator. It is safe to allocate an object from
// one instance of a default_alloc and deallocate it with another
// one. This effectively transfers its ownership to the second one.
// This may have undesirable effects on reference locality.
// The second parameter is unreferenced and serves only to allow the
// creation of multiple default_alloc instances.
//
// Note that containers built on different allocator instances have
// different types, limiting the utility of this approach.
#include <vcl_cstddef.h> // size_t lives here
const int VNL_ALLOC_ALIGN = 8;
const vcl_size_t VNL_ALLOC_MAX_BYTES = 256;
const vcl_size_t VNL_ALLOC_NFREELISTS = VNL_ALLOC_MAX_BYTES/VNL_ALLOC_ALIGN;
class vnl_alloc
{
static vcl_size_t ROUND_UP(vcl_size_t bytes) {
return (bytes + VNL_ALLOC_ALIGN-1) & ~(VNL_ALLOC_ALIGN - 1);
}
union obj;
friend union obj;
union obj {
union obj * free_list_link;
char client_data[1]; /* The client sees this. */
};
# if defined ( __SUNPRO_CC ) || defined ( _AIX )
static obj * free_list[];
// Specifying a size results in duplicate def for 4.1
# else
static obj * free_list[VNL_ALLOC_NFREELISTS];
# endif
static vcl_size_t FREELIST_INDEX(vcl_size_t bytes) {
return (bytes + VNL_ALLOC_ALIGN-1)/VNL_ALLOC_ALIGN - 1;
}
// Returns an object of size n, and optionally adds to size n free li*st.
static void *refill(vcl_size_t n);
// Allocates a chunk for nobjs of size size. nobjs may be reduced
// if it is inconvenient to allocate the requested number.
static char *chunk_alloc(vcl_size_t size, int &nobjs);
// Chunk allocation state.
static char *start_free;
static char *end_free;
static vcl_size_t heap_size;
class lock
{
public:
lock() {}
~lock() {}
};
friend class lock;
public:
// this one is needed for proper vcl_simple_alloc wrapping
typedef char value_type;
/* n must be > 0 */
static void * allocate(vcl_size_t n) {
obj * * my_free_list;
obj * result;
if (n > VNL_ALLOC_MAX_BYTES) {
return (void*)new char[n];
}
my_free_list = free_list + FREELIST_INDEX(n);
// Acquire the lock here with a constructor call.
// This ensures that it is released in exit or during stack
// unwinding.
result = *my_free_list;
if (result == 0) {
void *r = refill(ROUND_UP(n));
return r;
}
*my_free_list = result -> free_list_link;
return result;
};
/* p may not be 0 */
static void deallocate(void *p, vcl_size_t n)
{
obj *q = (obj *)p;
obj * * my_free_list;
if (n > VNL_ALLOC_MAX_BYTES) {
delete [] (char*)p;
return;
}
my_free_list = free_list + FREELIST_INDEX(n);
q -> free_list_link = *my_free_list;
*my_free_list = q;
}
static void * reallocate(void *p, vcl_size_t old_sz, vcl_size_t new_sz);
};
# endif // vnl_alloc_h_
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