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authorRincewindsHat <12514511+RincewindsHat@users.noreply.github.com>2023-01-31 13:46:01 (GMT)
committerRincewindsHat <12514511+RincewindsHat@users.noreply.github.com>2023-01-31 13:46:01 (GMT)
commite8bd88d1fcded01ccd066572eeaae1b507989cb3 (patch)
treec8e7be6c07c6f635f6e803e6a6ba9e7a95fee7c0 /gl/intprops.h
parent2ad962c13473607ca0d974bfaa516a0ed53ec73d (diff)
downloadmonitoring-plugins-e8bd88d1fcded01ccd066572eeaae1b507989cb3.tar.gz
Sync with the latest Gnulib code 668c0b8ffa
Diffstat (limited to 'gl/intprops.h')
-rw-r--r--gl/intprops.h250
1 files changed, 133 insertions, 117 deletions
diff --git a/gl/intprops.h b/gl/intprops.h
index f57f9b4..44b5e60 100644
--- a/gl/intprops.h
+++ b/gl/intprops.h
@@ -1,34 +1,24 @@
1/* intprops.h -- properties of integer types 1/* intprops.h -- properties of integer types
2 2
3 Copyright (C) 2001-2005, 2009-2013 Free Software Foundation, Inc. 3 Copyright (C) 2001-2023 Free Software Foundation, Inc.
4 4
5 This program is free software: you can redistribute it and/or modify 5 This program is free software: you can redistribute it and/or modify it
6 it under the terms of the GNU General Public License as published by 6 under the terms of the GNU Lesser General Public License as published
7 the Free Software Foundation; either version 3 of the License, or 7 by the Free Software Foundation; either version 2.1 of the License, or
8 (at your option) any later version. 8 (at your option) any later version.
9 9
10 This program is distributed in the hope that it will be useful, 10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details. 13 GNU Lesser General Public License for more details.
14 14
15 You should have received a copy of the GNU General Public License 15 You should have received a copy of the GNU Lesser General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
17
18/* Written by Paul Eggert. */
19 17
20#ifndef _GL_INTPROPS_H 18#ifndef _GL_INTPROPS_H
21#define _GL_INTPROPS_H 19#define _GL_INTPROPS_H
22 20
23#include <limits.h> 21#include "intprops-internal.h"
24
25/* Return an integer value, converted to the same type as the integer
26 expression E after integer type promotion. V is the unconverted value. */
27#define _GL_INT_CONVERT(e, v) (0 * (e) + (v))
28
29/* Act like _GL_INT_CONVERT (E, -V) but work around a bug in IRIX 6.5 cc; see
30 <http://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00406.html>. */
31#define _GL_INT_NEGATE_CONVERT(e, v) (0 * (e) - (v))
32 22
33/* The extra casts in the following macros work around compiler bugs, 23/* The extra casts in the following macros work around compiler bugs,
34 e.g., in Cray C 5.0.3.0. */ 24 e.g., in Cray C 5.0.3.0. */
@@ -37,72 +27,27 @@
37 an integer. */ 27 an integer. */
38#define TYPE_IS_INTEGER(t) ((t) 1.5 == 1) 28#define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
39 29
40/* True if negative values of the signed integer type T use two's 30/* True if the real type T is signed. */
41 complement, ones' complement, or signed magnitude representation, 31#define TYPE_SIGNED(t) _GL_TYPE_SIGNED (t)
42 respectively. Much GNU code assumes two's complement, but some
43 people like to be portable to all possible C hosts. */
44#define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
45#define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
46#define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)
47 32
48/* True if the signed integer expression E uses two's complement. */ 33/* Return 1 if the real expression E, after promotion, has a
49#define _GL_INT_TWOS_COMPLEMENT(e) (~ _GL_INT_CONVERT (e, 0) == -1) 34 signed or floating type. Do not evaluate E. */
35#define EXPR_SIGNED(e) _GL_EXPR_SIGNED (e)
50 36
51/* True if the arithmetic type T is signed. */
52#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
53 37
54/* Return 1 if the integer expression E, after integer promotion, has 38/* Minimum and maximum values for integer types and expressions. */
55 a signed type. */
56#define _GL_INT_SIGNED(e) (_GL_INT_NEGATE_CONVERT (e, 1) < 0)
57 39
58 40/* The width in bits of the integer type or expression T.
59/* Minimum and maximum values for integer types and expressions. These 41 Do not evaluate T. T must not be a bit-field expression.
60 macros have undefined behavior if T is signed and has padding bits. 42 Padding bits are not supported; this is checked at compile-time below. */
61 If this is a problem for you, please let us know how to fix it for 43#define TYPE_WIDTH(t) _GL_TYPE_WIDTH (t)
62 your host. */
63 44
64/* The maximum and minimum values for the integer type T. */ 45/* The maximum and minimum values for the integer type T. */
65#define TYPE_MINIMUM(t) \ 46#define TYPE_MINIMUM(t) ((t) ~ TYPE_MAXIMUM (t))
66 ((t) (! TYPE_SIGNED (t) \
67 ? (t) 0 \
68 : TYPE_SIGNED_MAGNITUDE (t) \
69 ? ~ (t) 0 \
70 : ~ TYPE_MAXIMUM (t)))
71#define TYPE_MAXIMUM(t) \ 47#define TYPE_MAXIMUM(t) \
72 ((t) (! TYPE_SIGNED (t) \ 48 ((t) (! TYPE_SIGNED (t) \
73 ? (t) -1 \ 49 ? (t) -1 \
74 : ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1))) 50 : ((((t) 1 << (TYPE_WIDTH (t) - 2)) - 1) * 2 + 1)))
75
76/* The maximum and minimum values for the type of the expression E,
77 after integer promotion. E should not have side effects. */
78#define _GL_INT_MINIMUM(e) \
79 (_GL_INT_SIGNED (e) \
80 ? - _GL_INT_TWOS_COMPLEMENT (e) - _GL_SIGNED_INT_MAXIMUM (e) \
81 : _GL_INT_CONVERT (e, 0))
82#define _GL_INT_MAXIMUM(e) \
83 (_GL_INT_SIGNED (e) \
84 ? _GL_SIGNED_INT_MAXIMUM (e) \
85 : _GL_INT_NEGATE_CONVERT (e, 1))
86#define _GL_SIGNED_INT_MAXIMUM(e) \
87 (((_GL_INT_CONVERT (e, 1) << (sizeof ((e) + 0) * CHAR_BIT - 2)) - 1) * 2 + 1)
88
89
90/* Return 1 if the __typeof__ keyword works. This could be done by
91 'configure', but for now it's easier to do it by hand. */
92#if 2 <= __GNUC__ || defined __IBM__TYPEOF__ || 0x5110 <= __SUNPRO_C
93# define _GL_HAVE___TYPEOF__ 1
94#else
95# define _GL_HAVE___TYPEOF__ 0
96#endif
97
98/* Return 1 if the integer type or expression T might be signed. Return 0
99 if it is definitely unsigned. This macro does not evaluate its argument,
100 and expands to an integer constant expression. */
101#if _GL_HAVE___TYPEOF__
102# define _GL_SIGNED_TYPE_OR_EXPR(t) TYPE_SIGNED (__typeof__ (t))
103#else
104# define _GL_SIGNED_TYPE_OR_EXPR(t) 1
105#endif
106 51
107/* Bound on length of the string representing an unsigned integer 52/* Bound on length of the string representing an unsigned integer
108 value representable in B bits. log10 (2.0) < 146/485. The 53 value representable in B bits. log10 (2.0) < 146/485. The
@@ -110,30 +55,31 @@
110#define INT_BITS_STRLEN_BOUND(b) (((b) * 146 + 484) / 485) 55#define INT_BITS_STRLEN_BOUND(b) (((b) * 146 + 484) / 485)
111 56
112/* Bound on length of the string representing an integer type or expression T. 57/* Bound on length of the string representing an integer type or expression T.
58 T must not be a bit-field expression.
59
113 Subtract 1 for the sign bit if T is signed, and then add 1 more for 60 Subtract 1 for the sign bit if T is signed, and then add 1 more for
114 a minus sign if needed. 61 a minus sign if needed.
115 62
116 Because _GL_SIGNED_TYPE_OR_EXPR sometimes returns 0 when its argument is 63 Because _GL_SIGNED_TYPE_OR_EXPR sometimes returns 1 when its argument is
117 signed, this macro may overestimate the true bound by one byte when 64 unsigned, this macro may overestimate the true bound by one byte when
118 applied to unsigned types of size 2, 4, 16, ... bytes. */ 65 applied to unsigned types of size 2, 4, 16, ... bytes. */
119#define INT_STRLEN_BOUND(t) \ 66#define INT_STRLEN_BOUND(t) \
120 (INT_BITS_STRLEN_BOUND (sizeof (t) * CHAR_BIT \ 67 (INT_BITS_STRLEN_BOUND (TYPE_WIDTH (t) - _GL_SIGNED_TYPE_OR_EXPR (t)) \
121 - _GL_SIGNED_TYPE_OR_EXPR (t)) \
122 + _GL_SIGNED_TYPE_OR_EXPR (t)) 68 + _GL_SIGNED_TYPE_OR_EXPR (t))
123 69
124/* Bound on buffer size needed to represent an integer type or expression T, 70/* Bound on buffer size needed to represent an integer type or expression T,
125 including the terminating null. */ 71 including the terminating null. T must not be a bit-field expression. */
126#define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1) 72#define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1)
127 73
128 74
129/* Range overflow checks. 75/* Range overflow checks.
130 76
131 The INT_<op>_RANGE_OVERFLOW macros return 1 if the corresponding C 77 The INT_<op>_RANGE_OVERFLOW macros return 1 if the corresponding C
132 operators might not yield numerically correct answers due to 78 operators overflow arithmetically when given the same arguments.
133 arithmetic overflow. They do not rely on undefined or 79 These macros do not rely on undefined or implementation-defined behavior.
134 implementation-defined behavior. Their implementations are simple 80 Although their implementations are simple and straightforward,
135 and straightforward, but they are a bit harder to use than the 81 they are harder to use and may be less efficient than the
136 INT_<op>_OVERFLOW macros described below. 82 INT_<op>_WRAPV, INT_<op>_OK, and INT_<op>_OVERFLOW macros described below.
137 83
138 Example usage: 84 Example usage:
139 85
@@ -157,6 +103,9 @@
157 must have minimum value MIN and maximum MAX. Unsigned types should 103 must have minimum value MIN and maximum MAX. Unsigned types should
158 use a zero MIN of the proper type. 104 use a zero MIN of the proper type.
159 105
106 Because all arguments are subject to integer promotions, these
107 macros typically do not work on types narrower than 'int'.
108
160 These macros are tuned for constant MIN and MAX. For commutative 109 These macros are tuned for constant MIN and MAX. For commutative
161 operations such as A + B, they are also tuned for constant B. */ 110 operations such as A + B, they are also tuned for constant B. */
162 111
@@ -177,14 +126,12 @@
177/* Return 1 if - A would overflow in [MIN,MAX] arithmetic. 126/* Return 1 if - A would overflow in [MIN,MAX] arithmetic.
178 See above for restrictions. */ 127 See above for restrictions. */
179#define INT_NEGATE_RANGE_OVERFLOW(a, min, max) \ 128#define INT_NEGATE_RANGE_OVERFLOW(a, min, max) \
180 ((min) < 0 \ 129 _GL_INT_NEGATE_RANGE_OVERFLOW (a, min, max)
181 ? (a) < - (max) \
182 : 0 < (a))
183 130
184/* Return 1 if A * B would overflow in [MIN,MAX] arithmetic. 131/* Return 1 if A * B would overflow in [MIN,MAX] arithmetic.
185 See above for restrictions. Avoid && and || as they tickle 132 See above for restrictions. Avoid && and || as they tickle
186 bugs in Sun C 5.11 2010/08/13 and other compilers; see 133 bugs in Sun C 5.11 2010/08/13 and other compilers; see
187 <http://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00401.html>. */ 134 <https://lists.gnu.org/r/bug-gnulib/2011-05/msg00401.html>. */
188#define INT_MULTIPLY_RANGE_OVERFLOW(a, b, min, max) \ 135#define INT_MULTIPLY_RANGE_OVERFLOW(a, b, min, max) \
189 ((b) < 0 \ 136 ((b) < 0 \
190 ? ((a) < 0 \ 137 ? ((a) < 0 \
@@ -223,24 +170,32 @@
223 ? (a) < (min) >> (b) \ 170 ? (a) < (min) >> (b) \
224 : (max) >> (b) < (a)) 171 : (max) >> (b) < (a))
225 172
226
227/* The _GL*_OVERFLOW macros have the same restrictions as the 173/* The _GL*_OVERFLOW macros have the same restrictions as the
228 *_RANGE_OVERFLOW macros, except that they do not assume that operands 174 *_RANGE_OVERFLOW macros, except that they do not assume that operands
229 (e.g., A and B) have the same type as MIN and MAX. Instead, they assume 175 (e.g., A and B) have the same type as MIN and MAX. Instead, they assume
230 that the result (e.g., A + B) has that type. */ 176 that the result (e.g., A + B) has that type. */
231#define _GL_ADD_OVERFLOW(a, b, min, max) \ 177#if _GL_HAS_BUILTIN_OVERFLOW_P
232 ((min) < 0 ? INT_ADD_RANGE_OVERFLOW (a, b, min, max) \ 178# define _GL_ADD_OVERFLOW(a, b, min, max) \
233 : (a) < 0 ? (b) <= (a) + (b) \ 179 __builtin_add_overflow_p (a, b, (__typeof__ ((a) + (b))) 0)
234 : (b) < 0 ? (a) <= (a) + (b) \ 180# define _GL_SUBTRACT_OVERFLOW(a, b, min, max) \
235 : (a) + (b) < (b)) 181 __builtin_sub_overflow_p (a, b, (__typeof__ ((a) - (b))) 0)
236#define _GL_SUBTRACT_OVERFLOW(a, b, min, max) \ 182# define _GL_MULTIPLY_OVERFLOW(a, b, min, max) \
237 ((min) < 0 ? INT_SUBTRACT_RANGE_OVERFLOW (a, b, min, max) \ 183 __builtin_mul_overflow_p (a, b, (__typeof__ ((a) * (b))) 0)
238 : (a) < 0 ? 1 \ 184#else
239 : (b) < 0 ? (a) - (b) <= (a) \ 185# define _GL_ADD_OVERFLOW(a, b, min, max) \
240 : (a) < (b)) 186 ((min) < 0 ? INT_ADD_RANGE_OVERFLOW (a, b, min, max) \
241#define _GL_MULTIPLY_OVERFLOW(a, b, min, max) \ 187 : (a) < 0 ? (b) <= (a) + (b) \
242 (((min) == 0 && (((a) < 0 && 0 < (b)) || ((b) < 0 && 0 < (a)))) \ 188 : (b) < 0 ? (a) <= (a) + (b) \
243 || INT_MULTIPLY_RANGE_OVERFLOW (a, b, min, max)) 189 : (a) + (b) < (b))
190# define _GL_SUBTRACT_OVERFLOW(a, b, min, max) \
191 ((min) < 0 ? INT_SUBTRACT_RANGE_OVERFLOW (a, b, min, max) \
192 : (a) < 0 ? 1 \
193 : (b) < 0 ? (a) - (b) <= (a) \
194 : (a) < (b))
195# define _GL_MULTIPLY_OVERFLOW(a, b, min, max) \
196 (((min) == 0 && (((a) < 0 && 0 < (b)) || ((b) < 0 && 0 < (a)))) \
197 || INT_MULTIPLY_RANGE_OVERFLOW (a, b, min, max))
198#endif
244#define _GL_DIVIDE_OVERFLOW(a, b, min, max) \ 199#define _GL_DIVIDE_OVERFLOW(a, b, min, max) \
245 ((min) < 0 ? (b) == _GL_INT_NEGATE_CONVERT (min, 1) && (a) < - (max) \ 200 ((min) < 0 ? (b) == _GL_INT_NEGATE_CONVERT (min, 1) && (a) < - (max) \
246 : (a) < 0 ? (b) <= (a) + (b) - 1 \ 201 : (a) < 0 ? (b) <= (a) + (b) - 1 \
@@ -262,22 +217,31 @@
262 : (a) % - (b)) \ 217 : (a) % - (b)) \
263 == 0) 218 == 0)
264 219
265 220/* Check for integer overflow, and report low order bits of answer.
266/* Integer overflow checks.
267 221
268 The INT_<op>_OVERFLOW macros return 1 if the corresponding C operators 222 The INT_<op>_OVERFLOW macros return 1 if the corresponding C operators
269 might not yield numerically correct answers due to arithmetic overflow. 223 might not yield numerically correct answers due to arithmetic overflow.
270 They work correctly on all known practical hosts, and do not rely 224 The INT_<op>_WRAPV macros compute the low-order bits of the sum,
225 difference, and product of two C integers, and return 1 if these
226 low-order bits are not numerically correct.
227 These macros work correctly on all known practical hosts, and do not rely
271 on undefined behavior due to signed arithmetic overflow. 228 on undefined behavior due to signed arithmetic overflow.
272 229
273 Example usage: 230 Example usage, assuming A and B are long int:
274 231
275 long int i = ...; 232 if (INT_MULTIPLY_OVERFLOW (a, b))
276 long int j = ...; 233 printf ("result would overflow\n");
277 if (INT_MULTIPLY_OVERFLOW (i, j))
278 printf ("multiply would overflow");
279 else 234 else
280 printf ("product is %ld", i * j); 235 printf ("result is %ld (no overflow)\n", a * b);
236
237 Example usage with WRAPV flavor:
238
239 long int result;
240 bool overflow = INT_MULTIPLY_WRAPV (a, b, &result);
241 printf ("result is %ld (%s)\n", result,
242 overflow ? "after overflow" : "no overflow");
243
244 Restrictions on these macros:
281 245
282 These macros do not check for all possible numerical problems or 246 These macros do not check for all possible numerical problems or
283 undefined or unspecified behavior: they do not check for division 247 undefined or unspecified behavior: they do not check for division
@@ -286,7 +250,23 @@
286 These macros may evaluate their arguments zero or multiple times, so the 250 These macros may evaluate their arguments zero or multiple times, so the
287 arguments should not have side effects. 251 arguments should not have side effects.
288 252
289 These macros are tuned for their last argument being a constant. 253 The WRAPV macros are not constant expressions. They support only
254 +, binary -, and *.
255
256 Because the WRAPV macros convert the result, they report overflow
257 in different circumstances than the OVERFLOW macros do. For
258 example, in the typical case with 16-bit 'short' and 32-bit 'int',
259 if A, B and *R are all of type 'short' then INT_ADD_OVERFLOW (A, B)
260 returns false because the addition cannot overflow after A and B
261 are converted to 'int', whereas INT_ADD_WRAPV (A, B, R) returns
262 true or false depending on whether the sum fits into 'short'.
263
264 These macros are tuned for their last input argument being a constant.
265
266 A, B, and *R should be integers; they need not be the same type,
267 and they need not be all signed or all unsigned.
268 However, none of the integer types should be bit-precise,
269 and *R's type should not be char, bool, or an enumeration type.
290 270
291 Return 1 if the integer expressions A * B, A - B, -A, A * B, A / B, 271 Return 1 if the integer expressions A * B, A - B, -A, A * B, A / B,
292 A % B, and A << B would overflow, respectively. */ 272 A % B, and A << B would overflow, respectively. */
@@ -295,8 +275,7 @@
295 _GL_BINARY_OP_OVERFLOW (a, b, _GL_ADD_OVERFLOW) 275 _GL_BINARY_OP_OVERFLOW (a, b, _GL_ADD_OVERFLOW)
296#define INT_SUBTRACT_OVERFLOW(a, b) \ 276#define INT_SUBTRACT_OVERFLOW(a, b) \
297 _GL_BINARY_OP_OVERFLOW (a, b, _GL_SUBTRACT_OVERFLOW) 277 _GL_BINARY_OP_OVERFLOW (a, b, _GL_SUBTRACT_OVERFLOW)
298#define INT_NEGATE_OVERFLOW(a) \ 278#define INT_NEGATE_OVERFLOW(a) _GL_INT_NEGATE_OVERFLOW (a)
299 INT_NEGATE_RANGE_OVERFLOW (a, _GL_INT_MINIMUM (a), _GL_INT_MAXIMUM (a))
300#define INT_MULTIPLY_OVERFLOW(a, b) \ 279#define INT_MULTIPLY_OVERFLOW(a, b) \
301 _GL_BINARY_OP_OVERFLOW (a, b, _GL_MULTIPLY_OVERFLOW) 280 _GL_BINARY_OP_OVERFLOW (a, b, _GL_MULTIPLY_OVERFLOW)
302#define INT_DIVIDE_OVERFLOW(a, b) \ 281#define INT_DIVIDE_OVERFLOW(a, b) \
@@ -313,7 +292,44 @@
313 Arguments should be free of side effects. */ 292 Arguments should be free of side effects. */
314#define _GL_BINARY_OP_OVERFLOW(a, b, op_result_overflow) \ 293#define _GL_BINARY_OP_OVERFLOW(a, b, op_result_overflow) \
315 op_result_overflow (a, b, \ 294 op_result_overflow (a, b, \
316 _GL_INT_MINIMUM (0 * (b) + (a)), \ 295 _GL_INT_MINIMUM (_GL_INT_CONVERT (a, b)), \
317 _GL_INT_MAXIMUM (0 * (b) + (a))) 296 _GL_INT_MAXIMUM (_GL_INT_CONVERT (a, b)))
297
298/* Store the low-order bits of A + B, A - B, A * B, respectively, into *R.
299 Return 1 if the result overflows. See above for restrictions. */
300#define INT_ADD_WRAPV(a, b, r) _GL_INT_ADD_WRAPV (a, b, r)
301#define INT_SUBTRACT_WRAPV(a, b, r) _GL_INT_SUBTRACT_WRAPV (a, b, r)
302#define INT_MULTIPLY_WRAPV(a, b, r) _GL_INT_MULTIPLY_WRAPV (a, b, r)
303
304/* The following macros compute A + B, A - B, and A * B, respectively.
305 If no overflow occurs, they set *R to the result and return 1;
306 otherwise, they return 0 and may modify *R.
307
308 Example usage:
309
310 long int result;
311 if (INT_ADD_OK (a, b, &result))
312 printf ("result is %ld\n", result);
313 else
314 printf ("overflow\n");
315
316 A, B, and *R should be integers; they need not be the same type,
317 and they need not be all signed or all unsigned.
318 However, none of the integer types should be bit-precise,
319 and *R's type should not be char, bool, or an enumeration type.
320
321 These macros work correctly on all known practical hosts, and do not rely
322 on undefined behavior due to signed arithmetic overflow.
323
324 These macros are not constant expressions.
325
326 These macros may evaluate their arguments zero or multiple times, so the
327 arguments should not have side effects.
328
329 These macros are tuned for B being a constant. */
330
331#define INT_ADD_OK(a, b, r) (! INT_ADD_WRAPV (a, b, r))
332#define INT_SUBTRACT_OK(a, b, r) (! INT_SUBTRACT_WRAPV (a, b, r))
333#define INT_MULTIPLY_OK(a, b, r) (! INT_MULTIPLY_WRAPV (a, b, r))
318 334
319#endif /* _GL_INTPROPS_H */ 335#endif /* _GL_INTPROPS_H */