MOM_safe_alloc.F90

1! This file is part of MOM6, the Modular Ocean Model version 6.
2! See the LICENSE file for licensing information.
3! SPDX-License-Identifier: Apache-2.0
4
5!> Convenience functions for safely allocating memory without
6!! accidentally reallocating pointer and causing memory leaks.
8
9implicit none ; private
10
11public safe_alloc_ptr, safe_alloc_alloc
12
13!> Allocate a pointer to a 1-d, 2-d or 3-d array
14interface safe_alloc_ptr
17end interface safe_alloc_ptr
18
19!> Allocate a 2-d or 3-d allocatable array
20interface safe_alloc_alloc
22 module procedure safe_alloc_allocatable_3d_6arg
23end interface safe_alloc_alloc
24
25! This combined interface might work with a later version of Fortran, but
26! it fails with the gnu F90 compiler.
27!
28! interface safe_alloc
29! module procedure safe_alloc_ptr_3d_2arg, safe_alloc_ptr_2d_2arg
30! module procedure safe_alloc_ptr_3d, safe_alloc_ptr_2d, safe_alloc_ptr_1d
31! module procedure safe_alloc_allocatable_3d, safe_alloc_allocatable_2d
32! end interface safe_alloc
33
34contains
35
36!> Allocate a pointer to a 1-d array
37subroutine safe_alloc_ptr_1d(ptr, i1, i2)
38 real, dimension(:), pointer :: ptr !< A pointer to allocate
39 integer, intent(in) :: i1 !< The size of the array, or its starting index if i2 is present
40 integer, optional, intent(in) :: i2 !< The ending index of the array
41 if (.not.associated(ptr)) then
42 if (present(i2)) then
43 allocate(ptr(i1:i2), source=0.0)
44 else
45 allocate(ptr(i1), source=0.0)
46 endif
47 endif
48end subroutine safe_alloc_ptr_1d
49
50!> Allocate a pointer to a 2-d array based on its dimension sizes
51subroutine safe_alloc_ptr_2d_2arg(ptr, ni, nj)
52 real, dimension(:,:), pointer :: ptr !< A pointer to allocate
53 integer, intent(in) :: ni !< The size of the 1st dimension of the array
54 integer, intent(in) :: nj !< The size of the 2nd dimension of the array
55 if (.not.associated(ptr)) then
56 allocate(ptr(ni,nj), source=0.0)
57 endif
58end subroutine safe_alloc_ptr_2d_2arg
59
60!> Allocate a pointer to a 3-d array based on its dimension sizes
61subroutine safe_alloc_ptr_3d_3arg(ptr, ni, nj, nk)
62 real, dimension(:,:,:), pointer :: ptr !< A pointer to allocate
63 integer, intent(in) :: ni !< The size of the 1st dimension of the array
64 integer, intent(in) :: nj !< The size of the 2nd dimension of the array
65 integer, intent(in) :: nk !< The size of the 3rd dimension of the array
66 if (.not.associated(ptr)) then
67 allocate(ptr(ni,nj,nk), source=0.0)
68 endif
69end subroutine safe_alloc_ptr_3d_3arg
70
71!> Allocate a pointer to a 2-d array based on its index starting and ending values
72subroutine safe_alloc_ptr_2d(ptr, is, ie, js, je)
73 real, dimension(:,:), pointer :: ptr !< A pointer to allocate
74 integer, intent(in) :: is !< The start index to allocate for the 1st dimension
75 integer, intent(in) :: ie !< The end index to allocate for the 1st dimension
76 integer, intent(in) :: js !< The start index to allocate for the 2nd dimension
77 integer, intent(in) :: je !< The end index to allocate for the 2nd dimension
78 if (.not.associated(ptr)) then
79 allocate(ptr(is:ie,js:je), source=0.0)
80 endif
81end subroutine safe_alloc_ptr_2d
82
83!> Allocate a pointer to a 3-d array based on its index starting and ending values
84subroutine safe_alloc_ptr_3d(ptr, is, ie, js, je, nk)
85 real, dimension(:,:,:), pointer :: ptr !< A pointer to allocate
86 integer, intent(in) :: is !< The start index to allocate for the 1st dimension
87 integer, intent(in) :: ie !< The end index to allocate for the 1st dimension
88 integer, intent(in) :: js !< The start index to allocate for the 2nd dimension
89 integer, intent(in) :: je !< The end index to allocate for the 2nd dimension
90 integer, intent(in) :: nk !< The size to allocate for the 3rd dimension
91 if (.not.associated(ptr)) then
92 allocate(ptr(is:ie,js:je,nk), source=0.0)
93 endif
94end subroutine safe_alloc_ptr_3d
95
96!> Allocate a pointer to a 3-d array based on its index starting and ending values
97subroutine safe_alloc_ptr_3d_6arg(ptr, is, ie, js, je, ks, ke)
98 real, dimension(:,:,:), pointer :: ptr !< A pointer to allocate
99 integer, intent(in) :: is !< The start index to allocate for the 1st dimension
100 integer, intent(in) :: ie !< The end index to allocate for the 1st dimension
101 integer, intent(in) :: js !< The start index to allocate for the 2nd dimension
102 integer, intent(in) :: je !< The end index to allocate for the 2nd dimension
103 integer, intent(in) :: ks !< The start index to allocate for the 3rd dimension
104 integer, intent(in) :: ke !< The end index to allocate for the 3rd dimension
105 if (.not.associated(ptr)) then
106 allocate(ptr(is:ie,js:je,ks:ke), source=0.0)
107 endif
108end subroutine safe_alloc_ptr_3d_6arg
109
110
111!> Allocate a 2-d allocatable array based on its index starting and ending values
112subroutine safe_alloc_allocatable_2d(ptr, is, ie, js, je)
113 real, dimension(:,:), allocatable :: ptr !< An allocatable array to allocate
114 integer, intent(in) :: is !< The start index to allocate for the 1st dimension
115 integer, intent(in) :: ie !< The end index to allocate for the 1st dimension
116 integer, intent(in) :: js !< The start index to allocate for the 2nd dimension
117 integer, intent(in) :: je !< The end index to allocate for the 2nd dimension
118 if (.not.allocated(ptr)) then
119 allocate(ptr(is:ie,js:je), source=0.0)
120 endif
121end subroutine safe_alloc_allocatable_2d
122
123!> Allocate a 3-d allocatable array based on its index starting and ending values
124!! and k-index size
125subroutine safe_alloc_allocatable_3d(ptr, is, ie, js, je, nk)
126 real, dimension(:,:,:), allocatable :: ptr !< An allocatable array to allocate
127 integer, intent(in) :: is !< The start index to allocate for the 1st dimension
128 integer, intent(in) :: ie !< The end index to allocate for the 1st dimension
129 integer, intent(in) :: js !< The start index to allocate for the 2nd dimension
130 integer, intent(in) :: je !< The end index to allocate for the 2nd dimension
131 integer, intent(in) :: nk !< The size to allocate for the 3rd dimension
132 if (.not.allocated(ptr)) then
133 allocate(ptr(is:ie,js:je,nk), source=0.0)
134 endif
135end subroutine safe_alloc_allocatable_3d
136
137!> Allocate a 3-d allocatable array based on its 6 index starting and ending values
138subroutine safe_alloc_allocatable_3d_6arg(ptr, is, ie, js, je, ks, ke)
139 real, dimension(:,:,:), allocatable :: ptr !< An allocatable array to allocate
140 integer, intent(in) :: is !< The start index to allocate for the 1st dimension
141 integer, intent(in) :: ie !< The end index to allocate for the 1st dimension
142 integer, intent(in) :: js !< The start index to allocate for the 2nd dimension
143 integer, intent(in) :: je !< The end index to allocate for the 2nd dimension
144 integer, intent(in) :: ks !< The start index to allocate for the 3rd dimension
145 integer, intent(in) :: ke !< The end index to allocate for the 3rd dimension
146 if (.not.allocated(ptr)) then
147 allocate(ptr(is:ie,js:je,ks:ke), source=0.0)
148 endif
150
151end module mom_safe_alloc