1 /* sb.c - string buffer manipulation routines
2 Copyright (C) 1994-2023 Free Software Foundation, Inc.
3
4 Written by Steve and Judy Chamberlain of Cygnus Support,
5 sac@cygnus.com
6
7 This file is part of GAS, the GNU Assembler.
8
9 GAS is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3, or (at your option)
12 any later version.
13
14 GAS is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with GAS; see the file COPYING. If not, write to the Free
21 Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
22 02110-1301, USA. */
23
24 #include "as.h"
25 #include "sb.h"
26
27 #include <limits.h>
28 #ifndef CHAR_BIT
29 #define CHAR_BIT 8
30 #endif
31
32 /* These routines are about manipulating strings.
33
34 They are managed in things called `sb's which is an abbreviation
35 for string buffers. An sb has to be created, things can be glued
36 on to it, and at the end of it's life it should be freed. The
37 contents should never be pointed at whilst it is still growing,
38 since it could be moved at any time
39
40 eg:
41 sb_new (&foo);
42 sb_grow... (&foo,...);
43 use foo->ptr[*];
44 sb_kill (&foo); */
45
46 /* Buffers start at INIT_ALLOC size, and roughly double each time we
47 go over the current allocation. MALLOC_OVERHEAD is a guess at the
48 system malloc overhead. We aim to not waste any memory in the
49 underlying page/chunk allocated by the system malloc. */
50 #define MALLOC_OVERHEAD (2 * sizeof (size_t))
51 #define INIT_ALLOC (64 - MALLOC_OVERHEAD - 1)
52
53 static void sb_check (sb *, size_t);
54
55 /* Initializes an sb. */
56
57 void
58 sb_build (sb *ptr, size_t size)
59 {
60 ptr->ptr = XNEWVEC (char, size + 1);
61 ptr->max = size;
62 ptr->len = 0;
63 }
64
65 void
66 sb_new (sb *ptr)
67 {
68 sb_build (ptr, INIT_ALLOC);
69 }
70
71 /* Deallocate the sb at ptr. */
72
73 void
74 sb_kill (sb *ptr)
75 {
76 free (ptr->ptr);
77 }
78
79 /* Add the sb at s to the end of the sb at ptr. */
80
81 void
82 sb_add_sb (sb *ptr, sb *s)
83 {
84 sb_check (ptr, s->len);
85 memcpy (ptr->ptr + ptr->len, s->ptr, s->len);
86 ptr->len += s->len;
87 }
88
89 /* Helper for sb_scrub_and_add_sb. */
90
91 static sb *sb_to_scrub;
92 static char *scrub_position;
93 static size_t
94 scrub_from_sb (char *buf, size_t buflen)
95 {
96 size_t copy;
97 copy = sb_to_scrub->len - (scrub_position - sb_to_scrub->ptr);
98 if (copy > buflen)
99 copy = buflen;
100 memcpy (buf, scrub_position, copy);
101 scrub_position += copy;
102 return copy;
103 }
104
105 /* Run the sb at s through do_scrub_chars and add the result to the sb
106 at ptr. */
107
108 void
109 sb_scrub_and_add_sb (sb *ptr, sb *s)
110 {
111 sb_to_scrub = s;
112 scrub_position = s->ptr;
113
114 /* do_scrub_chars can expand text, for example when replacing
115 # 123 "filename"
116 with
117 \t.linefile 123 "filename"
118 or when replacing a 'c with the decimal ascii number for c.
119 So we loop until the input S is consumed. */
120 while (1)
121 {
122 size_t copy = s->len - (scrub_position - s->ptr) + do_scrub_pending ();
123 if (copy == 0)
124 break;
125 sb_check (ptr, copy);
126 ptr->len += do_scrub_chars (scrub_from_sb, ptr->ptr + ptr->len,
127 ptr->max - ptr->len);
128 }
129
130 sb_to_scrub = 0;
131 scrub_position = 0;
132 }
133
134 /* Make sure that the sb at ptr has room for another len characters,
135 and grow it if it doesn't. */
136
137 static void
138 sb_check (sb *ptr, size_t len)
139 {
140 size_t want = ptr->len + len;
141
142 if (want > ptr->max)
143 {
144 size_t max;
145
146 want += MALLOC_OVERHEAD + 1;
147 if ((ssize_t) want < 0)
148 as_fatal ("string buffer overflow");
149 #if GCC_VERSION >= 3004
150 max = (size_t) 1 << (CHAR_BIT * sizeof (want)
151 - (sizeof (want) <= sizeof (long)
152 ? __builtin_clzl ((long) want)
153 : __builtin_clzll ((long long) want)));
154 #else
155 max = 128;
156 while (want > max)
157 max <<= 1;
158 #endif
159 max -= MALLOC_OVERHEAD + 1;
160 ptr->max = max;
161 ptr->ptr = XRESIZEVEC (char, ptr->ptr, max + 1);
162 }
163 }
164
165 /* Make the sb at ptr point back to the beginning. */
166
167 void
168 sb_reset (sb *ptr)
169 {
170 ptr->len = 0;
171 }
172
173 /* Add character c to the end of the sb at ptr. */
174
175 void
176 sb_add_char (sb *ptr, size_t c)
177 {
178 sb_check (ptr, 1);
179 ptr->ptr[ptr->len++] = c;
180 }
181
182 /* Add null terminated string s to the end of sb at ptr. */
183
184 void
185 sb_add_string (sb *ptr, const char *s)
186 {
187 size_t len = strlen (s);
188 sb_check (ptr, len);
189 memcpy (ptr->ptr + ptr->len, s, len);
190 ptr->len += len;
191 }
192
193 /* Add string at s of length len to sb at ptr */
194
195 void
196 sb_add_buffer (sb *ptr, const char *s, size_t len)
197 {
198 sb_check (ptr, len);
199 memcpy (ptr->ptr + ptr->len, s, len);
200 ptr->len += len;
201 }
202
203 /* Write terminating NUL and return string. */
204
205 char *
206 sb_terminate (sb *in)
207 {
208 in->ptr[in->len] = 0;
209 return in->ptr;
210 }
211
212 /* Start at the index idx into the string in sb at ptr and skip
213 whitespace. return the index of the first non whitespace character. */
214
215 size_t
216 sb_skip_white (size_t idx, sb *ptr)
217 {
218 while (idx < ptr->len
219 && (ptr->ptr[idx] == ' '
220 || ptr->ptr[idx] == '\t'))
221 idx++;
222 return idx;
223 }
224
225 /* Start at the index idx into the sb at ptr. skips whitespace,
226 a comma and any following whitespace. returns the index of the
227 next character. */
228
229 size_t
230 sb_skip_comma (size_t idx, sb *ptr)
231 {
232 while (idx < ptr->len
233 && (ptr->ptr[idx] == ' '
234 || ptr->ptr[idx] == '\t'))
235 idx++;
236
237 if (idx < ptr->len
238 && ptr->ptr[idx] == ',')
239 idx++;
240
241 while (idx < ptr->len
242 && (ptr->ptr[idx] == ' '
243 || ptr->ptr[idx] == '\t'))
244 idx++;
245
246 return idx;
247 }