1 /* input_file.c - Deal with Input Files - 2 Copyright (C) 1987-2016 Free Software Foundation, Inc. 3 4 This file is part of GAS, the GNU Assembler. 5 6 GAS is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3, or (at your option) 9 any later version. 10 11 GAS is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GAS; see the file COPYING. If not, write to the Free 18 Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA 19 02110-1301, USA. */ 20 21 /* Confines all details of reading source bytes to this module. 22 All O/S specific crocks should live here. 23 What we lose in "efficiency" we gain in modularity. 24 Note we don't need to #include the "as.h" file. No common coupling! */ 25 26 #include "as.h" 27 #include "input-file.h" 28 #include "safe-ctype.h" 29 30 /* This variable is non-zero if the file currently being read should be 31 preprocessed by app. It is zero if the file can be read straight in. */ 32 int preprocess = 0; 33 34 /* This code opens a file, then delivers BUFFER_SIZE character 35 chunks of the file on demand. 36 BUFFER_SIZE is supposed to be a number chosen for speed. 37 The caller only asks once what BUFFER_SIZE is, and asks before 38 the nature of the input files (if any) is known. */ 39 40 #define BUFFER_SIZE (32 * 1024) 41 42 /* We use static data: the data area is not sharable. */ 43 44 static FILE *f_in; 45 static const char *file_name; 46 47 /* Struct for saving the state of this module for file includes. */ 48 struct saved_file 49 { 50 FILE * f_in; 51 const char * file_name; 52 int preprocess; 53 char * app_save; 54 }; 55 56 /* These hooks accommodate most operating systems. */ 58 59 void 60 input_file_begin (void) 61 { 62 f_in = (FILE *) 0; 63 } 64 65 void 66 input_file_end (void) 67 { 68 } 69 70 /* Return BUFFER_SIZE. */ 71 size_t 72 input_file_buffer_size (void) 73 { 74 return (BUFFER_SIZE); 75 } 76 77 /* Push the state of our input, returning a pointer to saved info that 78 can be restored with input_file_pop (). */ 79 80 char * 81 input_file_push (void) 82 { 83 struct saved_file *saved; 84 85 saved = XNEW (struct saved_file); 86 87 saved->f_in = f_in; 88 saved->file_name = file_name; 89 saved->preprocess = preprocess; 90 if (preprocess) 91 saved->app_save = app_push (); 92 93 /* Initialize for new file. */ 94 input_file_begin (); 95 96 return (char *) saved; 97 } 98 99 void 100 input_file_pop (char *arg) 101 { 102 struct saved_file *saved = (struct saved_file *) arg; 103 104 input_file_end (); /* Close out old file. */ 105 106 f_in = saved->f_in; 107 file_name = saved->file_name; 108 preprocess = saved->preprocess; 109 if (preprocess) 110 app_pop (saved->app_save); 111 112 free (arg); 113 } 114 115 /* Open the specified file, "" means stdin. Filename must not be null. */ 117 118 void 119 input_file_open (const char *filename, 120 int pre) 121 { 122 int c; 123 char buf[80]; 124 125 preprocess = pre; 126 127 gas_assert (filename != 0); /* Filename may not be NULL. */ 128 if (filename[0]) 129 { 130 f_in = fopen (filename, FOPEN_RT); 131 file_name = filename; 132 } 133 else 134 { 135 /* Use stdin for the input file. */ 136 f_in = stdin; 137 /* For error messages. */ 138 file_name = _("{standard input}"); 139 } 140 141 if (f_in == NULL) 142 { 143 as_bad (_("can't open %s for reading: %s"), 144 file_name, xstrerror (errno)); 145 return; 146 } 147 148 c = getc (f_in); 149 150 if (ferror (f_in)) 151 { 152 as_bad (_("can't read from %s: %s"), 153 file_name, xstrerror (errno)); 154 155 fclose (f_in); 156 f_in = NULL; 157 return; 158 } 159 160 /* Check for an empty input file. */ 161 if (feof (f_in)) 162 { 163 fclose (f_in); 164 f_in = NULL; 165 return; 166 } 167 gas_assert (c != EOF); 168 169 if (c == '#') 170 { 171 /* Begins with comment, may not want to preprocess. */ 172 c = getc (f_in); 173 if (c == 'N') 174 { 175 if (fgets (buf, sizeof (buf), f_in) 176 && !strncmp (buf, "O_APP", 5) && ISSPACE (buf[5])) 177 preprocess = 0; 178 if (!strchr (buf, '\n')) 179 ungetc ('#', f_in); /* It was longer. */ 180 else 181 ungetc ('\n', f_in); 182 } 183 else if (c == 'A') 184 { 185 if (fgets (buf, sizeof (buf), f_in) 186 && !strncmp (buf, "PP", 2) && ISSPACE (buf[2])) 187 preprocess = 1; 188 if (!strchr (buf, '\n')) 189 ungetc ('#', f_in); 190 else 191 ungetc ('\n', f_in); 192 } 193 else if (c == '\n') 194 ungetc ('\n', f_in); 195 else 196 ungetc ('#', f_in); 197 } 198 else 199 ungetc (c, f_in); 200 } 201 202 /* Close input file. */ 203 204 void 205 input_file_close (void) 206 { 207 /* Don't close a null file pointer. */ 208 if (f_in != NULL) 209 fclose (f_in); 210 211 f_in = 0; 212 } 213 214 /* This function is passed to do_scrub_chars. */ 215 216 static size_t 217 input_file_get (char *buf, size_t buflen) 218 { 219 size_t size; 220 221 if (feof (f_in)) 222 return 0; 223 224 size = fread (buf, sizeof (char), buflen, f_in); 225 if (ferror (f_in)) 226 as_bad (_("can't read from %s: %s"), file_name, xstrerror (errno)); 227 return size; 228 } 229 230 /* Read a buffer from the input file. */ 231 232 char * 233 input_file_give_next_buffer (char *where /* Where to place 1st character of new buffer. */) 234 { 235 char *return_value; /* -> Last char of what we read, + 1. */ 236 size_t size; 237 238 if (f_in == (FILE *) 0) 239 return 0; 240 /* fflush (stdin); could be done here if you want to synchronise 241 stdin and stdout, for the case where our input file is stdin. 242 Since the assembler shouldn't do any output to stdout, we 243 don't bother to synch output and input. */ 244 if (preprocess) 245 size = do_scrub_chars (input_file_get, where, BUFFER_SIZE); 246 else 247 size = input_file_get (where, BUFFER_SIZE); 248 249 if (size) 250 return_value = where + size; 251 else 252 { 253 if (fclose (f_in)) 254 as_warn (_("can't close %s: %s"), file_name, xstrerror (errno)); 255 256 f_in = (FILE *) 0; 257 return_value = 0; 258 } 259 260 return return_value; 261 } 262
