1/* sb.c - string buffer manipulation routines
2   Copyright (C) 1994-2022 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
53static void sb_check (sb *, size_t);
54
55/* Initializes an sb.  */
56
57void
58sb_build (sb *ptr, size_t size)
59{
60  ptr->ptr = XNEWVEC (char, size + 1);
61  ptr->max = size;
62  ptr->len = 0;
63}
64
65void
66sb_new (sb *ptr)
67{
68  sb_build (ptr, INIT_ALLOC);
69}
70
71/* Deallocate the sb at ptr.  */
72
73void
74sb_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
81void
82sb_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
91static sb *sb_to_scrub;
92static char *scrub_position;
93static size_t
94scrub_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
108void
109sb_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
137static void
138sb_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
167void
168sb_reset (sb *ptr)
169{
170  ptr->len = 0;
171}
172
173/* Add character c to the end of the sb at ptr.  */
174
175void
176sb_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
184void
185sb_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
195void
196sb_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
205char *
206sb_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
215size_t
216sb_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
229size_t
230sb_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}
248