-/* PSPP - a program for statistical analysis.
- Copyright (C) 2007, 2009, 2010 Free Software Foundation, Inc.
-
- This program is free software: you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation, either version 3 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
-
-/* A interface to allow a temporary file to be treated as an
- array of data. */
-
-#include <config.h>
-
-#include <libpspp/temp-file.h>
-
-#include <errno.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-#include <libpspp/assertion.h>
-#include <libpspp/cast.h>
-
-#include "error.h"
-#include "xalloc.h"
-
-#include "gettext.h"
-#define _(msgid) gettext (msgid)
-
-struct temp_file
- {
- FILE *file; /* Underlying file. */
-
- /* Current byte offset in file. We track this manually,
- instead of using ftello, because in glibc ftello flushes
- the stream buffer, making the common case of sequential
- access to cases unreasonably slow. */
- off_t position;
- };
-
-/* Creates and returns a new temporary file. The temporary file
- will be automatically deleted when the process exits. */
-struct temp_file *
-temp_file_create (void)
-{
- struct temp_file *tf = xmalloc (sizeof *tf);
- tf->file = tmpfile ();
- if (tf->file == NULL)
- error (0, errno, _("failed to create temporary file"));
- tf->position = 0;
- return tf;
-}
-
-/* Closes and destroys temporary file TF. Returns true if I/O on
- TF always succeeded, false if an I/O error occurred at some
- point. */
-bool
-temp_file_destroy (struct temp_file *tf)
-{
- bool ok = true;
- if (tf != NULL)
- {
- ok = !temp_file_error (tf);
- if (tf->file != NULL)
- fclose (tf->file);
- free (tf);
- }
- return ok;
-}
-
-/* Seeks TF's underlying file to the start of `union value'
- VALUE_IDX within case CASE_IDX.
- Returns true if the seek is successful and TF is not
- otherwise tainted, false otherwise. */
-static bool
-do_seek (const struct temp_file *tf_, off_t offset)
-{
- struct temp_file *tf = CONST_CAST (struct temp_file *, tf_);
-
- if (!temp_file_error (tf))
- {
- if (tf->position == offset)
- return true;
- else if (fseeko (tf->file, offset, SEEK_SET) == 0)
- {
- tf->position = offset;
- return true;
- }
- else
- error (0, errno, _("seeking in temporary file"));
- }
-
- return false;
-}
-
-/* Reads BYTES bytes from TF's underlying file into BUFFER.
- TF must not be tainted upon entry into this function.
- Returns true if successful, false upon an I/O error (in which
- case TF is marked tainted). */
-static bool
-do_read (const struct temp_file *tf_, void *buffer, size_t bytes)
-{
- struct temp_file *tf = CONST_CAST (struct temp_file *, tf_);
-
- assert (!temp_file_error (tf));
- if (bytes > 0 && fread (buffer, bytes, 1, tf->file) != 1)
- {
- if (ferror (tf->file))
- error (0, errno, _("reading temporary file"));
- else if (feof (tf->file))
- error (0, 0, _("unexpected end of file reading temporary file"));
- else
- NOT_REACHED ();
- return false;
- }
- tf->position += bytes;
- return true;
-}
-
-/* Writes BYTES bytes from BUFFER into TF's underlying file.
- TF must not be tainted upon entry into this function.
- Returns true if successful, false upon an I/O error (in which
- case TF is marked tainted). */
-static bool
-do_write (struct temp_file *tf, const void *buffer, size_t bytes)
-{
- assert (!temp_file_error (tf));
- if (bytes > 0 && fwrite (buffer, bytes, 1, tf->file) != 1)
- {
- error (0, errno, _("writing to temporary file"));
- return false;
- }
- tf->position += bytes;
- return true;
-}
-
-/* Reads N bytes from TF at byte offset OFFSET into DATA.
- Returns true if successful, false on failure. */
-bool
-temp_file_read (const struct temp_file *tf, off_t offset, size_t n, void *data)
-{
- return do_seek (tf, offset) && do_read (tf, data, n);
-}
-
-/* Writes the N bytes in DATA to TF at byte offset OFFSET.
- Returns true if successful, false on failure. */
-bool
-temp_file_write (struct temp_file *tf, off_t offset, size_t n,
- const void *data)
-{
- return do_seek (tf, offset) && do_write (tf, data, n);
-}
-
-/* Returns true if an error has occurred in I/O on TF,
- false if no error has been detected. */
-bool
-temp_file_error (const struct temp_file *tf)
-{
- return tf->file == NULL || ferror (tf->file) || feof (tf->file);
-}