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1d506c26 | 1 | /* Copyright (C) 2019-2024 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 | { | |
7aeae94f | 48 | mpz_import (m_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 | ||
7aeae94f TT |
59 | mpz_ui_pow_ui (max.m_val, 2, buf.size () * HOST_CHAR_BIT - 1); |
60 | if (mpz_cmp (m_val, max.m_val) >= 0) | |
61 | mpz_submul_ui (m_val, max.m_val, 2); | |
b34c74ab JB |
62 | } |
63 | } | |
64 | ||
65 | /* See gmp-utils.h. */ | |
66 | ||
67 | void | |
1c805ba0 TT |
68 | gdb_mpz::export_bits (gdb::array_view<gdb_byte> buf, int endian, bool unsigned_p, |
69 | bool safe) const | |
63c457b9 | 70 | { |
c7c3708a TT |
71 | int sign = mpz_sgn (m_val); |
72 | if (sign == 0) | |
63c457b9 JB |
73 | { |
74 | /* Our value is zero, so no need to call mpz_export to do the work, | |
75 | especially since mpz_export's documentation explicitly says | |
76 | that the function is a noop in this case. Just write zero to | |
767c4b92 TT |
77 | BUF ourselves, if it is non-empty. In some languages, a |
78 | zero-bit type can exist and this is also fine. */ | |
79 | if (buf.size () > 0) | |
80 | memset (buf.data (), 0, buf.size ()); | |
63c457b9 JB |
81 | return; |
82 | } | |
83 | ||
767c4b92 TT |
84 | gdb_assert (buf.size () > 0); |
85 | ||
1c805ba0 | 86 | if (safe) |
63c457b9 | 87 | { |
1c805ba0 TT |
88 | /* Determine the maximum range of values that our buffer can |
89 | hold, and verify that VAL is within that range. */ | |
90 | ||
91 | gdb_mpz lo, hi; | |
92 | const size_t max_usable_bits = buf.size () * HOST_CHAR_BIT; | |
93 | if (unsigned_p) | |
94 | { | |
95 | lo = 0; | |
96 | ||
97 | mpz_ui_pow_ui (hi.m_val, 2, max_usable_bits); | |
98 | mpz_sub_ui (hi.m_val, hi.m_val, 1); | |
99 | } | |
100 | else | |
101 | { | |
102 | mpz_ui_pow_ui (lo.m_val, 2, max_usable_bits - 1); | |
103 | mpz_neg (lo.m_val, lo.m_val); | |
104 | ||
105 | mpz_ui_pow_ui (hi.m_val, 2, max_usable_bits - 1); | |
106 | mpz_sub_ui (hi.m_val, hi.m_val, 1); | |
107 | } | |
108 | ||
109 | if (mpz_cmp (m_val, lo.m_val) < 0 || mpz_cmp (m_val, hi.m_val) > 0) | |
110 | error (_("Cannot export value %s as %zu-bits %s integer" | |
111 | " (must be between %s and %s)"), | |
112 | this->str ().c_str (), | |
113 | max_usable_bits, | |
114 | unsigned_p ? _("unsigned") : _("signed"), | |
115 | lo.str ().c_str (), | |
116 | hi.str ().c_str ()); | |
63c457b9 JB |
117 | } |
118 | ||
c7c3708a TT |
119 | const gdb_mpz *exported_val = this; |
120 | gdb_mpz un_signed; | |
121 | if (sign < 0) | |
b34c74ab JB |
122 | { |
123 | /* mpz_export does not handle signed values, so create a positive | |
124 | value whose bit representation as an unsigned of the same length | |
125 | would be the same as our negative value. */ | |
c7c3708a TT |
126 | gdb_mpz neg_offset = gdb_mpz::pow (2, buf.size () * HOST_CHAR_BIT); |
127 | un_signed = *exported_val + neg_offset; | |
128 | exported_val = &un_signed; | |
b34c74ab JB |
129 | } |
130 | ||
1c805ba0 TT |
131 | /* If the value is too large, truncate it. */ |
132 | if (!safe | |
133 | && mpz_sizeinbase (exported_val->m_val, 2) > buf.size () * HOST_CHAR_BIT) | |
134 | { | |
135 | /* If we don't already have a copy, make it now. */ | |
136 | if (exported_val != &un_signed) | |
137 | { | |
138 | un_signed = *exported_val; | |
139 | exported_val = &un_signed; | |
140 | } | |
141 | ||
142 | un_signed.mask (buf.size () * HOST_CHAR_BIT); | |
143 | } | |
144 | ||
145 | /* It's possible that one of the above results in zero, which has to | |
146 | be handled specially. */ | |
147 | if (exported_val->sgn () == 0) | |
148 | { | |
149 | memset (buf.data (), 0, buf.size ()); | |
150 | return; | |
151 | } | |
152 | ||
63c457b9 JB |
153 | /* Do the export into a buffer allocated by GMP itself; that way, |
154 | we can detect cases where BUF is not large enough to export | |
33b5899f | 155 | our value, and thus avoid a buffer overflow. Normally, this should |
63c457b9 | 156 | never happen, since we verified earlier that the buffer is large |
33b5899f | 157 | enough to accommodate our value, but doing this allows us to be |
63c457b9 JB |
158 | extra safe with the export. |
159 | ||
160 | After verification that the export behaved as expected, we will | |
161 | copy the data over to BUF. */ | |
162 | ||
163 | size_t word_countp; | |
164 | gdb::unique_xmalloc_ptr<void> exported | |
165 | (mpz_export (NULL, &word_countp, -1 /* order */, buf.size () /* size */, | |
c7c3708a | 166 | endian, 0 /* nails */, exported_val->m_val)); |
63c457b9 JB |
167 | |
168 | gdb_assert (word_countp == 1); | |
169 | ||
170 | memcpy (buf.data (), exported.get (), buf.size ()); | |
b34c74ab JB |
171 | } |
172 | ||
173 | /* See gmp-utils.h. */ | |
174 | ||
175 | gdb_mpz | |
176 | gdb_mpq::get_rounded () const | |
177 | { | |
178 | /* Work with a positive number so as to make the "floor" rounding | |
179 | always round towards zero. */ | |
180 | ||
81768386 TT |
181 | gdb_mpq abs_val (m_val); |
182 | mpq_abs (abs_val.m_val, abs_val.m_val); | |
b34c74ab JB |
183 | |
184 | /* Convert our rational number into a quotient and remainder, | |
185 | with "floor" rounding, which in our case means rounding | |
186 | towards zero. */ | |
187 | ||
188 | gdb_mpz quotient, remainder; | |
7aeae94f | 189 | mpz_fdiv_qr (quotient.m_val, remainder.m_val, |
81768386 | 190 | mpq_numref (abs_val.m_val), mpq_denref (abs_val.m_val)); |
b34c74ab JB |
191 | |
192 | /* Multiply the remainder by 2, and see if it is greater or equal | |
193 | to abs_val's denominator. If yes, round to the next integer. */ | |
194 | ||
7aeae94f | 195 | mpz_mul_ui (remainder.m_val, remainder.m_val, 2); |
81768386 | 196 | if (mpz_cmp (remainder.m_val, mpq_denref (abs_val.m_val)) >= 0) |
7aeae94f | 197 | mpz_add_ui (quotient.m_val, quotient.m_val, 1); |
b34c74ab JB |
198 | |
199 | /* Re-apply the sign if needed. */ | |
81768386 | 200 | if (mpq_sgn (m_val) < 0) |
7aeae94f | 201 | mpz_neg (quotient.m_val, quotient.m_val); |
b34c74ab JB |
202 | |
203 | return quotient; | |
204 | } | |
205 | ||
206 | /* See gmp-utils.h. */ | |
207 | ||
208 | void | |
c9f0b43f | 209 | gdb_mpq::read_fixed_point (gdb::array_view<const gdb_byte> buf, |
b34c74ab JB |
210 | enum bfd_endian byte_order, bool unsigned_p, |
211 | const gdb_mpq &scaling_factor) | |
212 | { | |
213 | gdb_mpz vz; | |
c9f0b43f | 214 | vz.read (buf, byte_order, unsigned_p); |
b34c74ab | 215 | |
81768386 TT |
216 | mpq_set_z (m_val, vz.m_val); |
217 | mpq_mul (m_val, m_val, scaling_factor.m_val); | |
b34c74ab JB |
218 | } |
219 | ||
220 | /* See gmp-utils.h. */ | |
221 | ||
222 | void | |
c9f0b43f | 223 | gdb_mpq::write_fixed_point (gdb::array_view<gdb_byte> buf, |
b34c74ab JB |
224 | enum bfd_endian byte_order, bool unsigned_p, |
225 | const gdb_mpq &scaling_factor) const | |
226 | { | |
81768386 | 227 | gdb_mpq unscaled (m_val); |
b34c74ab | 228 | |
81768386 | 229 | mpq_div (unscaled.m_val, unscaled.m_val, scaling_factor.m_val); |
b34c74ab JB |
230 | |
231 | gdb_mpz unscaled_z = unscaled.get_rounded (); | |
c9f0b43f | 232 | unscaled_z.write (buf, byte_order, unsigned_p); |
b34c74ab JB |
233 | } |
234 | ||
235 | /* A wrapper around xrealloc that we can then register with GMP | |
236 | as the "realloc" function. */ | |
237 | ||
238 | static void * | |
239 | xrealloc_for_gmp (void *ptr, size_t old_size, size_t new_size) | |
240 | { | |
241 | return xrealloc (ptr, new_size); | |
242 | } | |
243 | ||
244 | /* A wrapper around xfree that we can then register with GMP | |
245 | as the "free" function. */ | |
246 | ||
247 | static void | |
248 | xfree_for_gmp (void *ptr, size_t size) | |
249 | { | |
250 | xfree (ptr); | |
251 | } | |
252 | ||
253 | void _initialize_gmp_utils (); | |
254 | ||
255 | void | |
256 | _initialize_gmp_utils () | |
257 | { | |
258 | /* Tell GMP to use GDB's memory management routines. */ | |
259 | mp_set_memory_functions (xmalloc, xrealloc_for_gmp, xfree_for_gmp); | |
260 | } |