1 /* Implementation of the ISO_C_BINDING library helper functions.
2 Copyright (C) 2007-2016 Free Software Foundation, Inc.
3 Contributed by Christopher Rickett.
4
5 This file is part of the GNU Fortran runtime library (libgfortran).
6
7 Libgfortran is free software; you can redistribute it and/or
8 modify it under the terms of the GNU General Public
9 License as published by the Free Software Foundation; either
10 version 3 of the License, or (at your option) any later version.
11
12 Libgfortran is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 Under Section 7 of GPL version 3, you are granted additional
18 permissions described in the GCC Runtime Library Exception, version
19 3.1, as published by the Free Software Foundation.
20
21 You should have received a copy of the GNU General Public License and
22 a copy of the GCC Runtime Library Exception along with this program;
23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 <http://www.gnu.org/licenses/>. */
25
26
27 /* Implement the functions and subroutines provided by the intrinsic
28 iso_c_binding module. */
29
30 #include "libgfortran.h"
31 #include "iso_c_binding.h"
32
33 #include <stdlib.h>
34
35
36 /* Set the fields of a Fortran pointer descriptor to point to the
37 given C address. It uses c_f_pointer_u0 for the common
38 fields, and will set up the information necessary if this C address
39 is to an array (i.e., offset, type, element size). The parameter
40 c_ptr_in represents the C address to have Fortran point to. The
41 parameter f_ptr_out is the Fortran pointer to associate with the C
42 address. The parameter shape is a one-dimensional array of integers
43 specifying the upper bound(s) of the array pointed to by the given C
44 address, if applicable. The shape parameter is optional in Fortran,
45 which will cause it to come in here as NULL. The parameter type is
46 the type of the data being pointed to (i.e.,libgfortran.h). The
47 elem_size parameter is the size, in bytes, of the data element being
48 pointed to. If the address is for an array, then the size needs to
49 be the size of a single element (i.e., for an array of doubles, it
50 needs to be the number of bytes for the size of one double). */
51
52 void
ISO_C_BINDING_PREFIX(c_f_pointer)53 ISO_C_BINDING_PREFIX (c_f_pointer) (void *c_ptr_in,
54 gfc_array_void *f_ptr_out,
55 const array_t *shape,
56 int type, int elemSize)
57 {
58 if (shape != NULL)
59 {
60 f_ptr_out->offset = 0;
61
62 /* Set the necessary dtype field for all pointers. */
63 f_ptr_out->dtype = 0;
64
65 /* Put in the element size. */
66 f_ptr_out->dtype = f_ptr_out->dtype | (elemSize << GFC_DTYPE_SIZE_SHIFT);
67
68 /* Set the data type (e.g., BT_INTEGER). */
69 f_ptr_out->dtype = f_ptr_out->dtype | (type << GFC_DTYPE_TYPE_SHIFT);
70 }
71
72 /* Use the generic version of c_f_pointer to set common fields. */
73 ISO_C_BINDING_PREFIX (c_f_pointer_u0) (c_ptr_in, f_ptr_out, shape);
74 }
75
76
77 /* A generic function to set the common fields of all descriptors, no
78 matter whether it's to a scalar or an array. Access is via the array
79 descrptor macros. Parameter shape is a rank 1 array of integers
80 containing the upper bound of each dimension of what f_ptr_out
81 points to. The length of this array must be EXACTLY the rank of
82 what f_ptr_out points to, as required by the draft (J3/04-007). If
83 f_ptr_out points to a scalar, then this parameter will be NULL. */
84
85 void
ISO_C_BINDING_PREFIX(c_f_pointer_u0)86 ISO_C_BINDING_PREFIX (c_f_pointer_u0) (void *c_ptr_in,
87 gfc_array_void *f_ptr_out,
88 const array_t *shape)
89 {
90 int i = 0;
91 int shapeSize = 0;
92
93 GFC_DESCRIPTOR_DATA (f_ptr_out) = c_ptr_in;
94
95 if (shape != NULL)
96 {
97 index_type source_stride, size;
98 index_type str = 1;
99 char *p;
100
101 f_ptr_out->offset = str;
102 shapeSize = 0;
103 p = shape->base_addr;
104 size = GFC_DESCRIPTOR_SIZE(shape);
105
106 source_stride = GFC_DESCRIPTOR_STRIDE_BYTES(shape,0);
107
108 /* shape's length (rank of the output array) */
109 shapeSize = GFC_DESCRIPTOR_EXTENT(shape,0);
110 for (i = 0; i < shapeSize; i++)
111 {
112 index_type ub;
113
114 /* Have to allow for the SHAPE array to be any valid kind for
115 an INTEGER type. */
116 switch (size)
117 {
118 #ifdef HAVE_GFC_INTEGER_1
119 case 1:
120 ub = *((GFC_INTEGER_1 *) p);
121 break;
122 #endif
123 #ifdef HAVE_GFC_INTEGER_2
124 case 2:
125 ub = *((GFC_INTEGER_2 *) p);
126 break;
127 #endif
128 #ifdef HAVE_GFC_INTEGER_4
129 case 4:
130 ub = *((GFC_INTEGER_4 *) p);
131 break;
132 #endif
133 #ifdef HAVE_GFC_INTEGER_8
134 case 8:
135 ub = *((GFC_INTEGER_8 *) p);
136 break;
137 #endif
138 #ifdef HAVE_GFC_INTEGER_16
139 case 16:
140 ub = *((GFC_INTEGER_16 *) p);
141 break;
142 #endif
143 default:
144 internal_error (NULL, "c_f_pointer_u0: Invalid size");
145 }
146 p += source_stride;
147
148 if (i != 0)
149 {
150 str = str * GFC_DESCRIPTOR_EXTENT(f_ptr_out,i-1);
151 f_ptr_out->offset += str;
152 }
153
154 /* Lower bound is 1, as specified by the draft. */
155 GFC_DIMENSION_SET(f_ptr_out->dim[i], 1, ub, str);
156 }
157
158 f_ptr_out->offset *= -1;
159
160 /* All we know is the rank, so set it, leaving the rest alone.
161 Make NO assumptions about the state of dtype coming in! If we
162 shift right by TYPE_SHIFT bits we'll throw away the existing
163 rank. Then, shift left by the same number to shift in zeros
164 and or with the new rank. */
165 f_ptr_out->dtype = ((f_ptr_out->dtype >> GFC_DTYPE_TYPE_SHIFT)
166 << GFC_DTYPE_TYPE_SHIFT) | shapeSize;
167 }
168 }
169
170
171 /* Sets the descriptor fields for a Fortran pointer to a derived type,
172 using c_f_pointer_u0 for the majority of the work. */
173
174 void
ISO_C_BINDING_PREFIX(c_f_pointer_d0)175 ISO_C_BINDING_PREFIX (c_f_pointer_d0) (void *c_ptr_in,
176 gfc_array_void *f_ptr_out,
177 const array_t *shape)
178 {
179 /* Set the common fields. */
180 ISO_C_BINDING_PREFIX (c_f_pointer_u0) (c_ptr_in, f_ptr_out, shape);
181
182 /* Preserve the size and rank bits, but reset the type. */
183 if (shape != NULL)
184 {
185 f_ptr_out->dtype = f_ptr_out->dtype & (~GFC_DTYPE_TYPE_MASK);
186 f_ptr_out->dtype = f_ptr_out->dtype
187 | (BT_DERIVED << GFC_DTYPE_TYPE_SHIFT);
188 }
189 }
190