gas/sb.c

   1 /* sb.c - string buffer manipulation routines
   2    Copyright (C) 1994-2020 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
  55 static void sb_check (sb *, size_t);
  56
  57 /* Initializes an sb.  */
  58
  59 void
  60 sb_build (sb *ptr, size_t size)
  61 {
  62   ptr->ptr = XNEWVEC (char, size + 1);
  63   ptr->max = size;
  64   ptr->len = 0;
  65 }
  66
  67 void
  68 sb_new (sb *ptr)
  69 {
  70   sb_build (ptr, INIT_ALLOC);
  71 }
  72
  73 /* Deallocate the sb at ptr.  */
  74
  75 void
  76 sb_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
  83 void
  84 sb_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
  93 static sb *sb_to_scrub;
  94 static char *scrub_position;
  95 static size_t
  96 scrub_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
 110 void
 111 sb_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
 126 static void
 127 sb_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
 156 void
 157 sb_reset (sb *ptr)
 158 {
 159   ptr->len = 0;
 160 }
 161
 162 /* Add character c to the end of the sb at ptr.  */
 163
 164 void
 165 sb_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
 173 void
 174 sb_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
 184 void
 185 sb_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
 194 char *
 195 sb_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
 204 size_t
 205 sb_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
 218 size_t
 219 sb_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 }