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260 lines
5.8 KiB
C
260 lines
5.8 KiB
C
/* input_file.c - Deal with Input Files -
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Copyright (C) 1987-2017 Free Software Foundation, Inc.
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This file is part of GAS, the GNU Assembler.
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GAS is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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GAS is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GAS; see the file COPYING. If not, write to the Free
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Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
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02110-1301, USA. */
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/* Confines all details of reading source bytes to this module.
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All O/S specific crocks should live here.
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What we lose in "efficiency" we gain in modularity.
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Note we don't need to #include the "as.h" file. No common coupling! */
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#include "as.h"
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#include "input-file.h"
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#include "safe-ctype.h"
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/* This variable is non-zero if the file currently being read should be
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preprocessed by app. It is zero if the file can be read straight in. */
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int preprocess = 0;
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/* This code opens a file, then delivers BUFFER_SIZE character
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chunks of the file on demand.
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BUFFER_SIZE is supposed to be a number chosen for speed.
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The caller only asks once what BUFFER_SIZE is, and asks before
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the nature of the input files (if any) is known. */
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#define BUFFER_SIZE (32 * 1024)
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/* We use static data: the data area is not sharable. */
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static FILE *f_in;
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static const char *file_name;
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/* Struct for saving the state of this module for file includes. */
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struct saved_file
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{
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FILE * f_in;
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const char * file_name;
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int preprocess;
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char * app_save;
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};
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/* These hooks accommodate most operating systems. */
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void
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input_file_begin (void)
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{
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f_in = (FILE *) 0;
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}
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void
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input_file_end (void)
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{
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}
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/* Return BUFFER_SIZE. */
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size_t
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input_file_buffer_size (void)
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{
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return (BUFFER_SIZE);
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}
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/* Push the state of our input, returning a pointer to saved info that
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can be restored with input_file_pop (). */
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char *
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input_file_push (void)
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{
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struct saved_file *saved;
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saved = XNEW (struct saved_file);
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saved->f_in = f_in;
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saved->file_name = file_name;
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saved->preprocess = preprocess;
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if (preprocess)
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saved->app_save = app_push ();
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/* Initialize for new file. */
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input_file_begin ();
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return (char *) saved;
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}
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void
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input_file_pop (char *arg)
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{
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struct saved_file *saved = (struct saved_file *) arg;
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input_file_end (); /* Close out old file. */
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f_in = saved->f_in;
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file_name = saved->file_name;
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preprocess = saved->preprocess;
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if (preprocess)
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app_pop (saved->app_save);
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free (arg);
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}
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/* Open the specified file, "" means stdin. Filename must not be null. */
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void
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input_file_open (const char *filename,
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int pre)
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{
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int c;
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char buf[80];
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preprocess = pre;
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gas_assert (filename != 0); /* Filename may not be NULL. */
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if (filename[0])
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{
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f_in = fopen (filename, FOPEN_RT);
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file_name = filename;
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}
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else
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{
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/* Use stdin for the input file. */
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f_in = stdin;
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/* For error messages. */
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file_name = _("{standard input}");
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}
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if (f_in == NULL)
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{
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as_bad (_("can't open %s for reading: %s"),
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file_name, xstrerror (errno));
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return;
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}
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c = getc (f_in);
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if (ferror (f_in))
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{
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as_bad (_("can't read from %s: %s"),
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file_name, xstrerror (errno));
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fclose (f_in);
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f_in = NULL;
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return;
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}
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/* Check for an empty input file. */
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if (feof (f_in))
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{
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fclose (f_in);
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f_in = NULL;
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return;
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}
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gas_assert (c != EOF);
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if (c == '#')
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{
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/* Begins with comment, may not want to preprocess. */
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c = getc (f_in);
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if (c == 'N')
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{
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if (fgets (buf, sizeof (buf), f_in)
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&& !strncmp (buf, "O_APP", 5) && ISSPACE (buf[5]))
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preprocess = 0;
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if (!strchr (buf, '\n'))
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ungetc ('#', f_in); /* It was longer. */
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else
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ungetc ('\n', f_in);
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}
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else if (c == 'A')
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{
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if (fgets (buf, sizeof (buf), f_in)
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&& !strncmp (buf, "PP", 2) && ISSPACE (buf[2]))
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preprocess = 1;
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if (!strchr (buf, '\n'))
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ungetc ('#', f_in);
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else
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ungetc ('\n', f_in);
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}
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else if (c == '\n')
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ungetc ('\n', f_in);
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else
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ungetc ('#', f_in);
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}
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else
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ungetc (c, f_in);
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}
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/* Close input file. */
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void
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input_file_close (void)
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{
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/* Don't close a null file pointer. */
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if (f_in != NULL)
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fclose (f_in);
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f_in = 0;
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}
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/* This function is passed to do_scrub_chars. */
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static size_t
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input_file_get (char *buf, size_t buflen)
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{
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size_t size;
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if (feof (f_in))
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return 0;
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size = fread (buf, sizeof (char), buflen, f_in);
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if (ferror (f_in))
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as_bad (_("can't read from %s: %s"), file_name, xstrerror (errno));
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return size;
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}
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/* Read a buffer from the input file. */
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char *
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input_file_give_next_buffer (char *where /* Where to place 1st character of new buffer. */)
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{
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char *return_value; /* -> Last char of what we read, + 1. */
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size_t size;
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if (f_in == (FILE *) 0)
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return 0;
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/* fflush (stdin); could be done here if you want to synchronise
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stdin and stdout, for the case where our input file is stdin.
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Since the assembler shouldn't do any output to stdout, we
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don't bother to synch output and input. */
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if (preprocess)
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size = do_scrub_chars (input_file_get, where, BUFFER_SIZE);
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else
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size = input_file_get (where, BUFFER_SIZE);
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if (size)
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return_value = where + size;
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else
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{
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if (fclose (f_in))
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as_warn (_("can't close %s: %s"), file_name, xstrerror (errno));
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f_in = (FILE *) 0;
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return_value = 0;
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}
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return return_value;
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}
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