gas/input-file.c

   1 /* input_file.c - Deal with Input Files -
   2    Copyright 1987, 1990, 1991, 1992, 1993, 1994, 1995, 1999, 2000, 2001, 2003
   3    Free Software Foundation, Inc.
   4
   5    This file is part of GAS, the GNU Assembler.
   6
   7    GAS is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2, or (at your option)
  10    any later version.
  11
  12    GAS is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GAS; see the file COPYING.  If not, write to the Free
  19    Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20    02111-1307, USA.  */
  21
  22 /* Confines all details of reading source bytes to this module.
  23    All O/S specific crocks should live here.
  24    What we lose in "efficiency" we gain in modularity.
  25    Note we don't need to #include the "as.h" file. No common coupling!  */
  26
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <errno.h>
  30 #include "as.h"
  31 #include "input-file.h"
  32 #include "safe-ctype.h"
  33
  34 static int input_file_get (char *, int);
  35
  36 /* This variable is non-zero if the file currently being read should be
  37    preprocessed by app.  It is zero if the file can be read straight in.  */
  38 int preprocess = 0;
  39
  40 /* This code opens a file, then delivers BUFFER_SIZE character
  41    chunks of the file on demand.
  42    BUFFER_SIZE is supposed to be a number chosen for speed.
  43    The caller only asks once what BUFFER_SIZE is, and asks before
  44    the nature of the input files (if any) is known.  */
  45
  46 #define BUFFER_SIZE (32 * 1024)
  47
  48 /* We use static data: the data area is not sharable.  */
  49
  50 static FILE *f_in;
  51 static char *file_name;
  52
  53 /* Struct for saving the state of this module for file includes.  */
  54 struct saved_file
  55   {
  56     FILE * f_in;
  57     char * file_name;
  58     int    preprocess;
  59     char * app_save;
  60   };
  61 \f
  62 /* These hooks accommodate most operating systems.  */
  63
  64 void
  65 input_file_begin (void)
  66 {
  67   f_in = (FILE *) 0;
  68 }
  69
  70 void
  71 input_file_end (void)
  72 {
  73 }
  74
  75 /* Return BUFFER_SIZE.  */
  76 unsigned int
  77 input_file_buffer_size (void)
  78 {
  79   return (BUFFER_SIZE);
  80 }
  81
  82 int
  83 input_file_is_open (void)
  84 {
  85   return f_in != (FILE *) 0;
  86 }
  87
  88 /* Push the state of our input, returning a pointer to saved info that
  89    can be restored with input_file_pop ().  */
  90
  91 char *
  92 input_file_push (void)
  93 {
  94   register struct saved_file *saved;
  95
  96   saved = (struct saved_file *) xmalloc (sizeof *saved);
  97
  98   saved->f_in = f_in;
  99   saved->file_name = file_name;
 100   saved->preprocess = preprocess;
 101   if (preprocess)
 102     saved->app_save = app_push ();
 103
 104   /* Initialize for new file.  */
 105   input_file_begin ();
 106
 107   return (char *) saved;
 108 }
 109
 110 void
 111 input_file_pop (char *arg)
 112 {
 113   register struct saved_file *saved = (struct saved_file *) arg;
 114
 115   input_file_end ();            /* Close out old file.  */
 116
 117   f_in = saved->f_in;
 118   file_name = saved->file_name;
 119   preprocess = saved->preprocess;
 120   if (preprocess)
 121     app_pop (saved->app_save);
 122
 123   free (arg);
 124 }
 125 \f
 126 void
 127 input_file_open (char *filename, /* "" means use stdin. Must not be 0.  */
 128                  int pre)
 129 {
 130   int c;
 131   char buf[80];
 132
 133   preprocess = pre;
 134
 135   assert (filename != 0);       /* Filename may not be NULL.  */
 136   if (filename[0])
 137     {
 138       f_in = fopen (filename, FOPEN_RT);
 139       file_name = filename;
 140     }
 141   else
 142     {
 143       /* Use stdin for the input file.  */
 144       f_in = stdin;
 145       /* For error messages.  */
 146       file_name = _("{standard input}");
 147     }
 148
 149   if (f_in)
 150     c = getc (f_in);
 151
 152   if (f_in == NULL || ferror (f_in))
 153     {
 154 #ifdef BFD_ASSEMBLER
 155       bfd_set_error (bfd_error_system_call);
 156 #endif
 157       as_perror (_("Can't open %s for reading"), file_name);
 158
 159       if (f_in)
 160         {
 161           fclose (f_in);
 162           f_in = NULL;
 163         }
 164       return;
 165     }
 166
 167   if (c == '#')
 168     {
 169       /* Begins with comment, may not want to preprocess.  */
 170       c = getc (f_in);
 171       if (c == 'N')
 172         {
 173           fgets (buf, 80, f_in);
 174           if (!strncmp (buf, "O_APP", 5) && ISSPACE (buf[5]))
 175             preprocess = 0;
 176           if (!strchr (buf, '\n'))
 177             ungetc ('#', f_in); /* It was longer.  */
 178           else
 179             ungetc ('\n', f_in);
 180         }
 181       else if (c == 'A')
 182         {
 183           fgets (buf, 80, f_in);
 184           if (!strncmp (buf, "PP", 2) && ISSPACE (buf[2]))
 185             preprocess = 1;
 186           if (!strchr (buf, '\n'))
 187             ungetc ('#', f_in);
 188           else
 189             ungetc ('\n', f_in);
 190         }
 191       else if (c == '\n')
 192         ungetc ('\n', f_in);
 193       else
 194         ungetc ('#', f_in);
 195     }
 196   else
 197     ungetc (c, f_in);
 198 }
 199
 200 /* Close input file.  */
 201
 202 void
 203 input_file_close (void)
 204 {
 205   /* Don't close a null file pointer.  */
 206   if (f_in != NULL)
 207     fclose (f_in);
 208
 209   f_in = 0;
 210 }
 211
 212 /* This function is passed to do_scrub_chars.  */
 213
 214 static int
 215 input_file_get (char *buf, int buflen)
 216 {
 217   int size;
 218
 219   size = fread (buf, sizeof (char), buflen, f_in);
 220   if (size < 0)
 221     {
 222 #ifdef BFD_ASSEMBLER
 223       bfd_set_error (bfd_error_system_call);
 224 #endif
 225       as_perror (_("Can't read from %s"), file_name);
 226       size = 0;
 227     }
 228   return size;
 229 }
 230
 231 /* Read a buffer from the input file.  */
 232
 233 char *
 234 input_file_give_next_buffer (char *where /* Where to place 1st character of new buffer.  */)
 235 {
 236   char *return_value;           /* -> Last char of what we read, + 1.  */
 237   register int size;
 238
 239   if (f_in == (FILE *) 0)
 240     return 0;
 241   /* fflush (stdin); could be done here if you want to synchronise
 242      stdin and stdout, for the case where our input file is stdin.
 243      Since the assembler shouldn't do any output to stdout, we
 244      don't bother to synch output and input.  */
 245   if (preprocess)
 246     size = do_scrub_chars (input_file_get, where, BUFFER_SIZE);
 247   else
 248     size = fread (where, sizeof (char), BUFFER_SIZE, f_in);
 249   if (size < 0)
 250     {
 251 #ifdef BFD_ASSEMBLER
 252       bfd_set_error (bfd_error_system_call);
 253 #endif
 254       as_perror (_("Can't read from %s"), file_name);
 255       size = 0;
 256     }
 257   if (size)
 258     return_value = where + size;
 259   else
 260     {
 261       if (fclose (f_in))
 262         {
 263 #ifdef BFD_ASSEMBLER
 264           bfd_set_error (bfd_error_system_call);
 265 #endif
 266           as_perror (_("Can't close %s"), file_name);
 267         }
 268       f_in = (FILE *) 0;
 269       return_value = 0;
 270     }
 271
 272   return return_value;
 273 }