gas/sb.c

   1 /* sb.c - string buffer manipulation routines
   2    Copyright 1994, 1995, 2000, 2003, 2005, 2006, 2007, 2009, 2012
   3    Free Software Foundation, Inc.
   4
   5    Written by Steve and Judy Chamberlain of Cygnus Support,
   6       sac@cygnus.com
   7
   8    This file is part of GAS, the GNU Assembler.
   9
  10    GAS is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3, or (at your option)
  13    any later version.
  14
  15    GAS is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with GAS; see the file COPYING.  If not, write to the Free
  22    Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
  23    02110-1301, USA.  */
  24
  25 #include "as.h"
  26 #include "sb.h"
  27
  28 #ifdef HAVE_LIMITS_H
  29 #include <limits.h>
  30 #endif
  31 #ifndef CHAR_BIT
  32 #define CHAR_BIT 8
  33 #endif
  34
  35 /* These routines are about manipulating strings.
  36
  37    They are managed in things called `sb's which is an abbreviation
  38    for string buffers.  An sb has to be created, things can be glued
  39    on to it, and at the end of it's life it should be freed.  The
  40    contents should never be pointed at whilst it is still growing,
  41    since it could be moved at any time
  42
  43    eg:
  44    sb_new (&foo);
  45    sb_grow... (&foo,...);
  46    use foo->ptr[*];
  47    sb_kill (&foo);  */
  48
  49 /* Buffers start at INIT_ALLOC size, and roughly double each time we
  50    go over the current allocation.  MALLOC_OVERHEAD is a guess at the
  51    system malloc overhead.  We aim to not waste any memory in the
  52    underlying page/chunk allocated by the system malloc.  */
  53 #define MALLOC_OVERHEAD (2 * sizeof (size_t))
  54 #define INIT_ALLOC (64 - MALLOC_OVERHEAD - 1)
  55
  56 static void sb_check (sb *, size_t);
  57
  58 /* Initializes an sb.  */
  59
  60 void
  61 sb_build (sb *ptr, size_t size)
  62 {
  63   ptr->ptr = xmalloc (size + 1);
  64   ptr->max = size;
  65   ptr->len = 0;
  66 }
  67
  68 void
  69 sb_new (sb *ptr)
  70 {
  71   sb_build (ptr, INIT_ALLOC);
  72 }
  73
  74 /* Deallocate the sb at ptr.  */
  75
  76 void
  77 sb_kill (sb *ptr)
  78 {
  79   free (ptr->ptr);
  80 }
  81
  82 /* Add the sb at s to the end of the sb at ptr.  */
  83
  84 void
  85 sb_add_sb (sb *ptr, sb *s)
  86 {
  87   sb_check (ptr, s->len);
  88   memcpy (ptr->ptr + ptr->len, s->ptr, s->len);
  89   ptr->len += s->len;
  90 }
  91
  92 /* Helper for sb_scrub_and_add_sb.  */
  93
  94 static sb *sb_to_scrub;
  95 static char *scrub_position;
  96 static size_t
  97 scrub_from_sb (char *buf, size_t buflen)
  98 {
  99   size_t copy;
 100   copy = sb_to_scrub->len - (scrub_position - sb_to_scrub->ptr);
 101   if (copy > buflen)
 102     copy = buflen;
 103   memcpy (buf, scrub_position, copy);
 104   scrub_position += copy;
 105   return copy;
 106 }
 107
 108 /* Run the sb at s through do_scrub_chars and add the result to the sb
 109    at ptr.  */
 110
 111 void
 112 sb_scrub_and_add_sb (sb *ptr, sb *s)
 113 {
 114   sb_to_scrub = s;
 115   scrub_position = s->ptr;
 116
 117   sb_check (ptr, s->len);
 118   ptr->len += do_scrub_chars (scrub_from_sb, ptr->ptr + ptr->len, s->len);
 119
 120   sb_to_scrub = 0;
 121   scrub_position = 0;
 122 }
 123
 124 /* Make sure that the sb at ptr has room for another len characters,
 125    and grow it if it doesn't.  */
 126
 127 static void
 128 sb_check (sb *ptr, size_t len)
 129 {
 130   size_t want = ptr->len + len;
 131
 132   if (want > ptr->max)
 133     {
 134       size_t max;
 135
 136       want += MALLOC_OVERHEAD + 1;
 137       if ((ssize_t) want < 0)
 138         as_fatal ("string buffer overflow");
 139 #if GCC_VERSION >= 3004
 140       max = (size_t) 1 << (CHAR_BIT * sizeof (want)
 141                            - (sizeof (want) <= sizeof (long)
 142                               ? __builtin_clzl ((long) want)
 143                               : __builtin_clzll ((long long) want)));
 144 #else
 145       max = 128;
 146       while (want > max)
 147         max <<= 1;
 148 #endif
 149       max -= MALLOC_OVERHEAD + 1;
 150       ptr->max = max;
 151       ptr->ptr = xrealloc (ptr->ptr, max + 1);
 152     }
 153 }
 154
 155 /* Make the sb at ptr point back to the beginning.  */
 156
 157 void
 158 sb_reset (sb *ptr)
 159 {
 160   ptr->len = 0;
 161 }
 162
 163 /* Add character c to the end of the sb at ptr.  */
 164
 165 void
 166 sb_add_char (sb *ptr, size_t c)
 167 {
 168   sb_check (ptr, 1);
 169   ptr->ptr[ptr->len++] = c;
 170 }
 171
 172 /* Add null terminated string s to the end of sb at ptr.  */
 173
 174 void
 175 sb_add_string (sb *ptr, const char *s)
 176 {
 177   size_t len = strlen (s);
 178   sb_check (ptr, len);
 179   memcpy (ptr->ptr + ptr->len, s, len);
 180   ptr->len += len;
 181 }
 182
 183 /* Add string at s of length len to sb at ptr */
 184
 185 void
 186 sb_add_buffer (sb *ptr, const char *s, size_t len)
 187 {
 188   sb_check (ptr, len);
 189   memcpy (ptr->ptr + ptr->len, s, len);
 190   ptr->len += len;
 191 }
 192
 193 /* Write terminating NUL and return string.  */
 194
 195 char *
 196 sb_terminate (sb *in)
 197 {
 198   in->ptr[in->len] = 0;
 199   return in->ptr;
 200 }
 201
 202 /* Start at the index idx into the string in sb at ptr and skip
 203    whitespace. return the index of the first non whitespace character.  */
 204
 205 size_t
 206 sb_skip_white (size_t idx, sb *ptr)
 207 {
 208   while (idx < ptr->len
 209          && (ptr->ptr[idx] == ' '
 210              || ptr->ptr[idx] == '\t'))
 211     idx++;
 212   return idx;
 213 }
 214
 215 /* Start at the index idx into the sb at ptr. skips whitespace,
 216    a comma and any following whitespace. returns the index of the
 217    next character.  */
 218
 219 size_t
 220 sb_skip_comma (size_t idx, sb *ptr)
 221 {
 222   while (idx < ptr->len
 223          && (ptr->ptr[idx] == ' '
 224              || ptr->ptr[idx] == '\t'))
 225     idx++;
 226
 227   if (idx < ptr->len
 228       && ptr->ptr[idx] == ',')
 229     idx++;
 230
 231   while (idx < ptr->len
 232          && (ptr->ptr[idx] == ' '
 233              || ptr->ptr[idx] == '\t'))
 234     idx++;
 235
 236   return idx;
 237 }