/*
** Copyright (C) 2002 TTTech Computertechnik AG. All rights reserved
** Schönbrunnerstraße 7, A--1040 Wien, Austria. office@tttech.com
** 
**
**++
** Name
**    ALF
**
** Purpose
**    Abstract large file 
**
** Revision Dates
**    23-Jan-2002 (CT) Creation
**    24-Jan-2002 (CT) Renamed from AFT to ALF
**    27-Feb-2002 (SM) Pretty much complete rewrite
**    ««revision-date»»···
**--
**
*/

/*
  ALF - abstract large files

  The intent of this package is to create something that behaves like a
  large file even on systems that don't support POSIX large files.  To the
  greatest extent possible, this just mimics the interface provided to work
  with stdio's FILE object.

  Author: Skip Montanaro (skip@pobox.com)
  Date: 2002-01-25
*/

/* $Id: alf.h,v 1.3 2002/04/25 21:07:15 montanaro Exp $ */
/* $Source: /cvsroot/largefiles/alf/src/alf.h,v $ */

#ifndef _ALF_H_
#define _ALF_H_

#if defined(_WIN32) && !defined(MS_WIN32)
#define MS_WIN32
#endif

#ifdef MS_WIN32
#define LONG_LONG __int64
#else
#define LONG_LONG long long
#endif

#include <sys/types.h>

#ifdef MS_WIN32
#include <windows.h>
#include <direct.h>
#else
#include <dirent.h>
#endif

#include <stdio.h>

#include "common.h"

BEGIN_C_DECLS

typedef struct _ALF_chunk {
    char *path;
#ifdef ALF_DEBUG
#define ALF_CHUNK_PAD_SIZE 4
    LONG_LONG pad1[ALF_CHUNK_PAD_SIZE];
#endif
    unsigned LONG_LONG offset;
#ifdef ALF_DEBUG
    LONG_LONG pad2[ALF_CHUNK_PAD_SIZE];
#endif
} ALF_chunk;

typedef struct _ALF {
    /* information provided by the user */
    char *mode;			/* mode the file was opened with */
    char *path;			/* path to the file's base dir */

    /* information calculated or stored for expediency */
    unsigned LONG_LONG position; /* current position in the ALF */
    unsigned LONG_LONG length;	/* ALF file's length */
    /*@null@*/
    FILE *current;		/* current active file */
    int _needs_flush;
#ifdef REOPEN_ON_WRITE
    int _reopen_on_write;       /* work around MS bug... */
#endif

    /* bookkeeping stuff */
    unsigned int nchunks;	/* number of chunks making up ALF */
    unsigned int current_chunk; /* current chunk assoc w/ current file */
    /*@null@*/
    ALF_chunk *chunks;		/* offset info for each element file */

    unsigned int eof;
    unsigned int error;
} ALF;

ALF *alf_open (const char *path, const char *mode, unsigned int use_large);
/* ERRNO: fopen(3), malloc(3) */

ALF *alf_reopen (const char *path, const char *mode, unsigned int use_large,
		 ALF *stream);
/* ERRNO: fopen(3), malloc(3), fclose(3), fflush(3) */

int alf_close (ALF *stream);
/* ERRNO: fclose(3) */

size_t alf_read (/*@out@*/ void *ptr, size_t size, size_t nmemb, ALF *stream);
/* ERRNO: fclose(3), fflush(3) */

size_t alf_write (const void *ptr, size_t size, size_t nmemb, ALF *stream);
/* ERRNO: fclose(3), fflush(3) */

int alf_flush (ALF *stream);
/* ERRNO: fflush(3) */

int alf_seek (ALF *stream, LONG_LONG offset, int whence);
/* ERRNO: fseek(3), fclose(3), fflush(3) */

unsigned LONG_LONG alf_tell (ALF *stream);
/* ERRNO: ftell */

void alf_rewind (ALF *stream);
/* ERRNO: none */

int alf_supports_large_files (void);

int alf_putc (int c, ALF *stream);
/* ERRNO: fclose(3), fflush(3) */

int alf_puts (const char *s, ALF *stream);
/* ERRNO: fclose(3), fflush(3) */

int alf_truncate (ALF *stream, unsigned LONG_LONG length);
/* ERRNO: fclose(3), fflush(3), truncate(3) */

int alf_getc (ALF *stream);
/* ERRNO: fclose(3), fflush(3) */

char *alf_gets (char *s, int size, ALF *stream);
/* ERRNO: fclose(3), fflush(3) */

int alf_eof (ALF *stream);
int alf_error (ALF *stream);
int alf_clearerr (ALF *stream);

/* TBD */
#if 0
int alf_printf (ALF *stream, const char *format, ...);
int alf_scanf (ALF *stream, const char *format, ...);
#endif

#define LONG32_MAX	2147483647L
#define LONG32_MIN	(-LONG32_MAX-1L)
#define LONG64_MAX	9223372036854775807L
#define LONG64_MIN	(-LONG64_MAX-1L)
#define ULONG32_MAX	4294967295UL
#define ULONG64_MAX	18446744073709551615UL

END_C_DECLS

#endif /* _ALF_H_ */

/*
 * Local Variables: ***
 * c-basic-offset: 4 ***
 * indent-tabs-mode: nil ***
 * End: ***
 */