1 /* Helper function for cshift functions.
2 Copyright (C) 2008-2016 Free Software Foundation, Inc.
3 Contributed by Thomas Koenig <tkoenig@gcc.gnu.org>
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 #include "libgfortran.h"
27 #include <stdlib.h>
28 #include <assert.h>
29 #include <string.h>
30
31
32 #if defined (HAVE_GFC_INTEGER_8)
33
34 void
cshift0_i8(gfc_array_i8 * ret,const gfc_array_i8 * array,ptrdiff_t shift,int which)35 cshift0_i8 (gfc_array_i8 *ret, const gfc_array_i8 *array, ptrdiff_t shift,
36 int which)
37 {
38 /* r.* indicates the return array. */
39 index_type rstride[GFC_MAX_DIMENSIONS];
40 index_type rstride0;
41 index_type roffset;
42 GFC_INTEGER_8 *rptr;
43
44 /* s.* indicates the source array. */
45 index_type sstride[GFC_MAX_DIMENSIONS];
46 index_type sstride0;
47 index_type soffset;
48 const GFC_INTEGER_8 *sptr;
49
50 index_type count[GFC_MAX_DIMENSIONS];
51 index_type extent[GFC_MAX_DIMENSIONS];
52 index_type dim;
53 index_type len;
54 index_type n;
55
56 which = which - 1;
57 sstride[0] = 0;
58 rstride[0] = 0;
59
60 extent[0] = 1;
61 count[0] = 0;
62 n = 0;
63 /* Initialized for avoiding compiler warnings. */
64 roffset = 1;
65 soffset = 1;
66 len = 0;
67
68 for (dim = 0; dim < GFC_DESCRIPTOR_RANK (array); dim++)
69 {
70 if (dim == which)
71 {
72 roffset = GFC_DESCRIPTOR_STRIDE(ret,dim);
73 if (roffset == 0)
74 roffset = 1;
75 soffset = GFC_DESCRIPTOR_STRIDE(array,dim);
76 if (soffset == 0)
77 soffset = 1;
78 len = GFC_DESCRIPTOR_EXTENT(array,dim);
79 }
80 else
81 {
82 count[n] = 0;
83 extent[n] = GFC_DESCRIPTOR_EXTENT(array,dim);
84 rstride[n] = GFC_DESCRIPTOR_STRIDE(ret,dim);
85 sstride[n] = GFC_DESCRIPTOR_STRIDE(array,dim);
86 n++;
87 }
88 }
89 if (sstride[0] == 0)
90 sstride[0] = 1;
91 if (rstride[0] == 0)
92 rstride[0] = 1;
93
94 dim = GFC_DESCRIPTOR_RANK (array);
95 rstride0 = rstride[0];
96 sstride0 = sstride[0];
97 rptr = ret->base_addr;
98 sptr = array->base_addr;
99
100 /* Avoid the costly modulo for trivially in-bound shifts. */
101 if (shift < 0 || shift >= len)
102 {
103 shift = len == 0 ? 0 : shift % (ptrdiff_t)len;
104 if (shift < 0)
105 shift += len;
106 }
107
108 while (rptr)
109 {
110 /* Do the shift for this dimension. */
111
112 /* If elements are contiguous, perform the operation
113 in two block moves. */
114 if (soffset == 1 && roffset == 1)
115 {
116 size_t len1 = shift * sizeof (GFC_INTEGER_8);
117 size_t len2 = (len - shift) * sizeof (GFC_INTEGER_8);
118 memcpy (rptr, sptr + shift, len2);
119 memcpy (rptr + (len - shift), sptr, len1);
120 }
121 else
122 {
123 /* Otherwise, we will have to perform the copy one element at
124 a time. */
125 GFC_INTEGER_8 *dest = rptr;
126 const GFC_INTEGER_8 *src = &sptr[shift * soffset];
127
128 for (n = 0; n < len - shift; n++)
129 {
130 *dest = *src;
131 dest += roffset;
132 src += soffset;
133 }
134 for (src = sptr, n = 0; n < shift; n++)
135 {
136 *dest = *src;
137 dest += roffset;
138 src += soffset;
139 }
140 }
141
142 /* Advance to the next section. */
143 rptr += rstride0;
144 sptr += sstride0;
145 count[0]++;
146 n = 0;
147 while (count[n] == extent[n])
148 {
149 /* When we get to the end of a dimension, reset it and increment
150 the next dimension. */
151 count[n] = 0;
152 /* We could precalculate these products, but this is a less
153 frequently used path so probably not worth it. */
154 rptr -= rstride[n] * extent[n];
155 sptr -= sstride[n] * extent[n];
156 n++;
157 if (n >= dim - 1)
158 {
159 /* Break out of the loop. */
160 rptr = NULL;
161 break;
162 }
163 else
164 {
165 count[n]++;
166 rptr += rstride[n];
167 sptr += sstride[n];
168 }
169 }
170 }
171
172 return;
173 }
174
175 #endif
176