1/* sb.c - string buffer manipulation routines
2   Copyright (C) 1994-2017 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#ifdef HAVE_LIMITS_H
28#include <limits.h>
29#endif
30#ifndef CHAR_BIT
31#define CHAR_BIT 8
32#endif
33
34/* These routines are about manipulating strings.
35
36   They are managed in things called `sb's which is an abbreviation
37   for string buffers.  An sb has to be created, things can be glued
38   on to it, and at the end of it's life it should be freed.  The
39   contents should never be pointed at whilst it is still growing,
40   since it could be moved at any time
41
42   eg:
43   sb_new (&foo);
44   sb_grow... (&foo,...);
45   use foo->ptr[*];
46   sb_kill (&foo);  */
47
48/* Buffers start at INIT_ALLOC size, and roughly double each time we
49   go over the current allocation.  MALLOC_OVERHEAD is a guess at the
50   system malloc overhead.  We aim to not waste any memory in the
51   underlying page/chunk allocated by the system malloc.  */
52#define MALLOC_OVERHEAD (2 * sizeof (size_t))
53#define INIT_ALLOC (64 - MALLOC_OVERHEAD - 1)
54
55static void sb_check (sb *, size_t);
56
57/* Initializes an sb.  */
58
59void
60sb_build (sb *ptr, size_t size)
61{
62  ptr->ptr = XNEWVEC (char, size + 1);
63  ptr->max = size;
64  ptr->len = 0;
65}
66
67void
68sb_new (sb *ptr)
69{
70  sb_build (ptr, INIT_ALLOC);
71}
72
73/* Deallocate the sb at ptr.  */
74
75void
76sb_kill (sb *ptr)
77{
78  free (ptr->ptr);
79}
80
81/* Add the sb at s to the end of the sb at ptr.  */
82
83void
84sb_add_sb (sb *ptr, sb *s)
85{
86  sb_check (ptr, s->len);
87  memcpy (ptr->ptr + ptr->len, s->ptr, s->len);
88  ptr->len += s->len;
89}
90
91/* Helper for sb_scrub_and_add_sb.  */
92
93static sb *sb_to_scrub;
94static char *scrub_position;
95static size_t
96scrub_from_sb (char *buf, size_t buflen)
97{
98  size_t copy;
99  copy = sb_to_scrub->len - (scrub_position - sb_to_scrub->ptr);
100  if (copy > buflen)
101    copy = buflen;
102  memcpy (buf, scrub_position, copy);
103  scrub_position += copy;
104  return copy;
105}
106
107/* Run the sb at s through do_scrub_chars and add the result to the sb
108   at ptr.  */
109
110void
111sb_scrub_and_add_sb (sb *ptr, sb *s)
112{
113  sb_to_scrub = s;
114  scrub_position = s->ptr;
115
116  sb_check (ptr, s->len);
117  ptr->len += do_scrub_chars (scrub_from_sb, ptr->ptr + ptr->len, s->len);
118
119  sb_to_scrub = 0;
120  scrub_position = 0;
121}
122
123/* Make sure that the sb at ptr has room for another len characters,
124   and grow it if it doesn't.  */
125
126static void
127sb_check (sb *ptr, size_t len)
128{
129  size_t want = ptr->len + len;
130
131  if (want > ptr->max)
132    {
133      size_t max;
134
135      want += MALLOC_OVERHEAD + 1;
136      if ((ssize_t) want < 0)
137	as_fatal ("string buffer overflow");
138#if GCC_VERSION >= 3004
139      max = (size_t) 1 << (CHAR_BIT * sizeof (want)
140			   - (sizeof (want) <= sizeof (long)
141			      ? __builtin_clzl ((long) want)
142			      : __builtin_clzll ((long long) want)));
143#else
144      max = 128;
145      while (want > max)
146	max <<= 1;
147#endif
148      max -= MALLOC_OVERHEAD + 1;
149      ptr->max = max;
150      ptr->ptr = XRESIZEVEC (char, ptr->ptr, max + 1);
151    }
152}
153
154/* Make the sb at ptr point back to the beginning.  */
155
156void
157sb_reset (sb *ptr)
158{
159  ptr->len = 0;
160}
161
162/* Add character c to the end of the sb at ptr.  */
163
164void
165sb_add_char (sb *ptr, size_t c)
166{
167  sb_check (ptr, 1);
168  ptr->ptr[ptr->len++] = c;
169}
170
171/* Add null terminated string s to the end of sb at ptr.  */
172
173void
174sb_add_string (sb *ptr, const char *s)
175{
176  size_t len = strlen (s);
177  sb_check (ptr, len);
178  memcpy (ptr->ptr + ptr->len, s, len);
179  ptr->len += len;
180}
181
182/* Add string at s of length len to sb at ptr */
183
184void
185sb_add_buffer (sb *ptr, const char *s, size_t len)
186{
187  sb_check (ptr, len);
188  memcpy (ptr->ptr + ptr->len, s, len);
189  ptr->len += len;
190}
191
192/* Write terminating NUL and return string.  */
193
194char *
195sb_terminate (sb *in)
196{
197  in->ptr[in->len] = 0;
198  return in->ptr;
199}
200
201/* Start at the index idx into the string in sb at ptr and skip
202   whitespace. return the index of the first non whitespace character.  */
203
204size_t
205sb_skip_white (size_t idx, sb *ptr)
206{
207  while (idx < ptr->len
208	 && (ptr->ptr[idx] == ' '
209	     || ptr->ptr[idx] == '\t'))
210    idx++;
211  return idx;
212}
213
214/* Start at the index idx into the sb at ptr. skips whitespace,
215   a comma and any following whitespace. returns the index of the
216   next character.  */
217
218size_t
219sb_skip_comma (size_t idx, sb *ptr)
220{
221  while (idx < ptr->len
222	 && (ptr->ptr[idx] == ' '
223	     || ptr->ptr[idx] == '\t'))
224    idx++;
225
226  if (idx < ptr->len
227      && ptr->ptr[idx] == ',')
228    idx++;
229
230  while (idx < ptr->len
231	 && (ptr->ptr[idx] == ' '
232	     || ptr->ptr[idx] == '\t'))
233    idx++;
234
235  return idx;
236}
237