gas/input-file.c

   1 /* input_file.c - Deal with Input Files -
   2    Copyright 1987, 1990, 1991, 1992, 1993, 1994, 1995, 1999, 2000, 2001,
   3    2002, 2003, 2005
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GAS, the GNU Assembler.
   7
   8    GAS is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2, or (at your option)
  11    any later version.
  12
  13    GAS is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with GAS; see the file COPYING.  If not, write to the Free
  20    Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
  21    02110-1301, USA.  */
  22
  23 /* Confines all details of reading source bytes to this module.
  24    All O/S specific crocks should live here.
  25    What we lose in "efficiency" we gain in modularity.
  26    Note we don't need to #include the "as.h" file. No common coupling!  */
  27
  28 #include <stdio.h>
  29 #include <string.h>
  30 #include <errno.h>
  31 #include "as.h"
  32 #include "input-file.h"
  33 #include "safe-ctype.h"
  34
  35 static int input_file_get (char *, int);
  36
  37 /* This variable is non-zero if the file currently being read should be
  38    preprocessed by app.  It is zero if the file can be read straight in.  */
  39 int preprocess = 0;
  40
  41 /* This code opens a file, then delivers BUFFER_SIZE character
  42    chunks of the file on demand.
  43    BUFFER_SIZE is supposed to be a number chosen for speed.
  44    The caller only asks once what BUFFER_SIZE is, and asks before
  45    the nature of the input files (if any) is known.  */
  46
  47 #define BUFFER_SIZE (32 * 1024)
  48
  49 /* We use static data: the data area is not sharable.  */
  50
  51 static FILE *f_in;
  52 static char *file_name;
  53
  54 /* Struct for saving the state of this module for file includes.  */
  55 struct saved_file
  56   {
  57     FILE * f_in;
  58     char * file_name;
  59     int    preprocess;
  60     char * app_save;
  61   };
  62 \f
  63 /* These hooks accommodate most operating systems.  */
  64
  65 void
  66 input_file_begin (void)
  67 {
  68   f_in = (FILE *) 0;
  69 }
  70
  71 void
  72 input_file_end (void)
  73 {
  74 }
  75
  76 /* Return BUFFER_SIZE.  */
  77 unsigned int
  78 input_file_buffer_size (void)
  79 {
  80   return (BUFFER_SIZE);
  81 }
  82
  83 /* Push the state of our input, returning a pointer to saved info that
  84    can be restored with input_file_pop ().  */
  85
  86 char *
  87 input_file_push (void)
  88 {
  89   register struct saved_file *saved;
  90
  91   saved = (struct saved_file *) xmalloc (sizeof *saved);
  92
  93   saved->f_in = f_in;
  94   saved->file_name = file_name;
  95   saved->preprocess = preprocess;
  96   if (preprocess)
  97     saved->app_save = app_push ();
  98
  99   /* Initialize for new file.  */
 100   input_file_begin ();
 101
 102   return (char *) saved;
 103 }
 104
 105 void
 106 input_file_pop (char *arg)
 107 {
 108   register struct saved_file *saved = (struct saved_file *) arg;
 109
 110   input_file_end ();            /* Close out old file.  */
 111
 112   f_in = saved->f_in;
 113   file_name = saved->file_name;
 114   preprocess = saved->preprocess;
 115   if (preprocess)
 116     app_pop (saved->app_save);
 117
 118   free (arg);
 119 }
 120 \f
 121 void
 122 input_file_open (char *filename, /* "" means use stdin. Must not be 0.  */
 123                  int pre)
 124 {
 125   int c;
 126   char buf[80];
 127
 128   preprocess = pre;
 129
 130   assert (filename != 0);       /* Filename may not be NULL.  */
 131   if (filename[0])
 132     {
 133       f_in = fopen (filename, FOPEN_RT);
 134       file_name = filename;
 135     }
 136   else
 137     {
 138       /* Use stdin for the input file.  */
 139       f_in = stdin;
 140       /* For error messages.  */
 141       file_name = _("{standard input}");
 142     }
 143
 144   if (f_in == NULL)
 145     {
 146 #ifdef BFD_ASSEMBLER
 147       bfd_set_error (bfd_error_system_call);
 148 #endif
 149       as_perror (_("Can't open %s for reading"), file_name);
 150       return;
 151     }
 152
 153   c = getc (f_in);
 154
 155   if (ferror (f_in))
 156     {
 157 #ifdef BFD_ASSEMBLER
 158       bfd_set_error (bfd_error_system_call);
 159 #endif
 160       as_perror (_("Can't open %s for reading"), file_name);
 161
 162       fclose (f_in);
 163       f_in = NULL;
 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 }