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3666a048 | 1 | /* Copyright (C) 2019-2021 Free Software Foundation, Inc. |
b34c74ab JB |
2 | |
3 | This file is part of GDB. | |
4 | ||
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 3 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
17 | ||
18 | #include "gmp-utils.h" | |
19 | ||
20 | /* See gmp-utils.h. */ | |
21 | ||
987b6703 JB |
22 | std::string |
23 | gmp_string_printf (const char *fmt, ...) | |
b34c74ab JB |
24 | { |
25 | va_list vp; | |
b34c74ab JB |
26 | |
27 | va_start (vp, fmt); | |
987b6703 | 28 | int size = gmp_vsnprintf (NULL, 0, fmt, vp); |
b34c74ab JB |
29 | va_end (vp); |
30 | ||
987b6703 JB |
31 | std::string str (size, '\0'); |
32 | ||
33 | /* C++11 and later guarantee std::string uses contiguous memory and | |
34 | always includes the terminating '\0'. */ | |
35 | va_start (vp, fmt); | |
36 | gmp_vsprintf (&str[0], fmt, vp); | |
37 | va_end (vp); | |
38 | ||
39 | return str; | |
b34c74ab JB |
40 | } |
41 | ||
42 | /* See gmp-utils.h. */ | |
43 | ||
44 | void | |
c9f0b43f | 45 | gdb_mpz::read (gdb::array_view<const gdb_byte> buf, enum bfd_endian byte_order, |
b34c74ab JB |
46 | bool unsigned_p) |
47 | { | |
c9f0b43f | 48 | mpz_import (val, 1 /* count */, -1 /* order */, buf.size () /* size */, |
b34c74ab | 49 | byte_order == BFD_ENDIAN_BIG ? 1 : -1 /* endian */, |
c9f0b43f | 50 | 0 /* nails */, buf.data () /* op */); |
b34c74ab JB |
51 | |
52 | if (!unsigned_p) | |
53 | { | |
54 | /* The value was imported as if it was a positive value, | |
55 | as mpz_import does not handle signs. If the original value | |
56 | was in fact negative, we need to adjust VAL accordingly. */ | |
57 | gdb_mpz max; | |
58 | ||
3c7ba803 | 59 | mpz_ui_pow_ui (max.val, 2, buf.size () * HOST_CHAR_BIT - 1); |
b34c74ab JB |
60 | if (mpz_cmp (val, max.val) >= 0) |
61 | mpz_submul_ui (val, max.val, 2); | |
62 | } | |
63 | } | |
64 | ||
65 | /* See gmp-utils.h. */ | |
66 | ||
67 | void | |
c9f0b43f | 68 | gdb_mpz::write (gdb::array_view<gdb_byte> buf, enum bfd_endian byte_order, |
b34c74ab JB |
69 | bool unsigned_p) const |
70 | { | |
63c457b9 JB |
71 | this->safe_export |
72 | (buf, byte_order == BFD_ENDIAN_BIG ? 1 : -1 /* endian */, unsigned_p); | |
73 | } | |
74 | ||
75 | /* See gmp-utils.h. */ | |
76 | ||
77 | void | |
78 | gdb_mpz::safe_export (gdb::array_view<gdb_byte> buf, | |
79 | int endian, bool unsigned_p) const | |
80 | { | |
81 | gdb_assert (buf.size () > 0); | |
82 | ||
83 | if (mpz_sgn (val) == 0) | |
84 | { | |
85 | /* Our value is zero, so no need to call mpz_export to do the work, | |
86 | especially since mpz_export's documentation explicitly says | |
87 | that the function is a noop in this case. Just write zero to | |
88 | BUF ourselves. */ | |
89 | memset (buf.data (), 0, buf.size ()); | |
90 | return; | |
91 | } | |
92 | ||
93 | /* Determine the maximum range of values that our buffer can hold, | |
94 | and verify that VAL is within that range. */ | |
95 | ||
96 | gdb_mpz lo, hi; | |
97 | const size_t max_usable_bits = buf.size () * HOST_CHAR_BIT; | |
98 | if (unsigned_p) | |
99 | { | |
100 | lo = 0; | |
101 | ||
102 | mpz_ui_pow_ui (hi.val, 2, max_usable_bits); | |
103 | mpz_sub_ui (hi.val, hi.val, 1); | |
104 | } | |
105 | else | |
106 | { | |
107 | mpz_ui_pow_ui (lo.val, 2, max_usable_bits - 1); | |
108 | mpz_neg (lo.val, lo.val); | |
109 | ||
110 | mpz_ui_pow_ui (hi.val, 2, max_usable_bits - 1); | |
111 | mpz_sub_ui (hi.val, hi.val, 1); | |
112 | } | |
113 | ||
114 | if (mpz_cmp (val, lo.val) < 0 || mpz_cmp (val, hi.val) > 0) | |
115 | error (_("Cannot export value %s as %zu-bits %s integer" | |
116 | " (must be between %s and %s)"), | |
117 | this->str ().c_str (), | |
118 | max_usable_bits, | |
119 | unsigned_p ? _("unsigned") : _("signed"), | |
120 | lo.str ().c_str (), | |
121 | hi.str ().c_str ()); | |
122 | ||
b34c74ab JB |
123 | gdb_mpz exported_val (val); |
124 | ||
63c457b9 | 125 | if (mpz_cmp_ui (exported_val.val, 0) < 0) |
b34c74ab JB |
126 | { |
127 | /* mpz_export does not handle signed values, so create a positive | |
128 | value whose bit representation as an unsigned of the same length | |
129 | would be the same as our negative value. */ | |
130 | gdb_mpz neg_offset; | |
131 | ||
3c7ba803 | 132 | mpz_ui_pow_ui (neg_offset.val, 2, buf.size () * HOST_CHAR_BIT); |
b34c74ab JB |
133 | mpz_add (exported_val.val, exported_val.val, neg_offset.val); |
134 | } | |
135 | ||
63c457b9 JB |
136 | /* Do the export into a buffer allocated by GMP itself; that way, |
137 | we can detect cases where BUF is not large enough to export | |
138 | our value, and thus avoid a buffer overlow. Normally, this should | |
139 | never happen, since we verified earlier that the buffer is large | |
140 | enough to accomodate our value, but doing this allows us to be | |
141 | extra safe with the export. | |
142 | ||
143 | After verification that the export behaved as expected, we will | |
144 | copy the data over to BUF. */ | |
145 | ||
146 | size_t word_countp; | |
147 | gdb::unique_xmalloc_ptr<void> exported | |
148 | (mpz_export (NULL, &word_countp, -1 /* order */, buf.size () /* size */, | |
149 | endian, 0 /* nails */, exported_val.val)); | |
150 | ||
151 | gdb_assert (word_countp == 1); | |
152 | ||
153 | memcpy (buf.data (), exported.get (), buf.size ()); | |
b34c74ab JB |
154 | } |
155 | ||
156 | /* See gmp-utils.h. */ | |
157 | ||
158 | gdb_mpz | |
159 | gdb_mpq::get_rounded () const | |
160 | { | |
161 | /* Work with a positive number so as to make the "floor" rounding | |
162 | always round towards zero. */ | |
163 | ||
164 | gdb_mpq abs_val (val); | |
165 | mpq_abs (abs_val.val, abs_val.val); | |
166 | ||
167 | /* Convert our rational number into a quotient and remainder, | |
168 | with "floor" rounding, which in our case means rounding | |
169 | towards zero. */ | |
170 | ||
171 | gdb_mpz quotient, remainder; | |
172 | mpz_fdiv_qr (quotient.val, remainder.val, | |
173 | mpq_numref (abs_val.val), mpq_denref (abs_val.val)); | |
174 | ||
175 | /* Multiply the remainder by 2, and see if it is greater or equal | |
176 | to abs_val's denominator. If yes, round to the next integer. */ | |
177 | ||
178 | mpz_mul_ui (remainder.val, remainder.val, 2); | |
179 | if (mpz_cmp (remainder.val, mpq_denref (abs_val.val)) >= 0) | |
180 | mpz_add_ui (quotient.val, quotient.val, 1); | |
181 | ||
182 | /* Re-apply the sign if needed. */ | |
183 | if (mpq_sgn (val) < 0) | |
184 | mpz_neg (quotient.val, quotient.val); | |
185 | ||
186 | return quotient; | |
187 | } | |
188 | ||
189 | /* See gmp-utils.h. */ | |
190 | ||
191 | void | |
c9f0b43f | 192 | gdb_mpq::read_fixed_point (gdb::array_view<const gdb_byte> buf, |
b34c74ab JB |
193 | enum bfd_endian byte_order, bool unsigned_p, |
194 | const gdb_mpq &scaling_factor) | |
195 | { | |
196 | gdb_mpz vz; | |
c9f0b43f | 197 | vz.read (buf, byte_order, unsigned_p); |
b34c74ab JB |
198 | |
199 | mpq_set_z (val, vz.val); | |
200 | mpq_mul (val, val, scaling_factor.val); | |
201 | } | |
202 | ||
203 | /* See gmp-utils.h. */ | |
204 | ||
205 | void | |
c9f0b43f | 206 | gdb_mpq::write_fixed_point (gdb::array_view<gdb_byte> buf, |
b34c74ab JB |
207 | enum bfd_endian byte_order, bool unsigned_p, |
208 | const gdb_mpq &scaling_factor) const | |
209 | { | |
210 | gdb_mpq unscaled (val); | |
211 | ||
212 | mpq_div (unscaled.val, unscaled.val, scaling_factor.val); | |
213 | ||
214 | gdb_mpz unscaled_z = unscaled.get_rounded (); | |
c9f0b43f | 215 | unscaled_z.write (buf, byte_order, unsigned_p); |
b34c74ab JB |
216 | } |
217 | ||
218 | /* A wrapper around xrealloc that we can then register with GMP | |
219 | as the "realloc" function. */ | |
220 | ||
221 | static void * | |
222 | xrealloc_for_gmp (void *ptr, size_t old_size, size_t new_size) | |
223 | { | |
224 | return xrealloc (ptr, new_size); | |
225 | } | |
226 | ||
227 | /* A wrapper around xfree that we can then register with GMP | |
228 | as the "free" function. */ | |
229 | ||
230 | static void | |
231 | xfree_for_gmp (void *ptr, size_t size) | |
232 | { | |
233 | xfree (ptr); | |
234 | } | |
235 | ||
236 | void _initialize_gmp_utils (); | |
237 | ||
238 | void | |
239 | _initialize_gmp_utils () | |
240 | { | |
241 | /* Tell GMP to use GDB's memory management routines. */ | |
242 | mp_set_memory_functions (xmalloc, xrealloc_for_gmp, xfree_for_gmp); | |
243 | } |