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) - __builtin_clzl (want));
 141 #else
 142       max = 128;
 143       while (want > max)
 144         max <<= 1;
 145 #endif
 146       max -= MALLOC_OVERHEAD + 1;
 147       ptr->max = max;
 148       ptr->ptr = xrealloc (ptr->ptr, max + 1);
 149     }
 150 }
 151
 152 /* Make the sb at ptr point back to the beginning.  */
 153
 154 void
 155 sb_reset (sb *ptr)
 156 {
 157   ptr->len = 0;
 158 }
 159
 160 /* Add character c to the end of the sb at ptr.  */
 161
 162 void
 163 sb_add_char (sb *ptr, size_t c)
 164 {
 165   sb_check (ptr, 1);
 166   ptr->ptr[ptr->len++] = c;
 167 }
 168
 169 /* Add null terminated string s to the end of sb at ptr.  */
 170
 171 void
 172 sb_add_string (sb *ptr, const char *s)
 173 {
 174   size_t len = strlen (s);
 175   sb_check (ptr, len);
 176   memcpy (ptr->ptr + ptr->len, s, len);
 177   ptr->len += len;
 178 }
 179
 180 /* Add string at s of length len to sb at ptr */
 181
 182 void
 183 sb_add_buffer (sb *ptr, const char *s, size_t len)
 184 {
 185   sb_check (ptr, len);
 186   memcpy (ptr->ptr + ptr->len, s, len);
 187   ptr->len += len;
 188 }
 189
 190 /* Write terminating NUL and return string.  */
 191
 192 char *
 193 sb_terminate (sb *in)
 194 {
 195   in->ptr[in->len] = 0;
 196   return in->ptr;
 197 }
 198
 199 /* Start at the index idx into the string in sb at ptr and skip
 200    whitespace. return the index of the first non whitespace character.  */
 201
 202 size_t
 203 sb_skip_white (size_t idx, sb *ptr)
 204 {
 205   while (idx < ptr->len
 206          && (ptr->ptr[idx] == ' '
 207              || ptr->ptr[idx] == '\t'))
 208     idx++;
 209   return idx;
 210 }
 211
 212 /* Start at the index idx into the sb at ptr. skips whitespace,
 213    a comma and any following whitespace. returns the index of the
 214    next character.  */
 215
 216 size_t
 217 sb_skip_comma (size_t idx, sb *ptr)
 218 {
 219   while (idx < ptr->len
 220          && (ptr->ptr[idx] == ' '
 221              || ptr->ptr[idx] == '\t'))
 222     idx++;
 223
 224   if (idx < ptr->len
 225       && ptr->ptr[idx] == ',')
 226     idx++;
 227
 228   while (idx < ptr->len
 229          && (ptr->ptr[idx] == ' '
 230              || ptr->ptr[idx] == '\t'))
 231     idx++;
 232
 233   return idx;
 234 }