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/* $Id$ */
/** @file fileio.cpp Standard In/Out file operations */
#include "stdafx.h"
#include "openttd.h"
#include "fileio.h"
#include "functions.h"
#include "string.h"
#include "macros.h"
#include "variables.h"
#include "debug.h"
/*************************************************/
/* FILE IO ROUTINES ******************************/
/*************************************************/
#define FIO_BUFFER_SIZE 512
#define MAX_HANDLES 64
typedef struct {
byte *buffer, *buffer_end; ///< position pointer in local buffer and last valid byte of buffer
uint32 pos; ///< current (system) position in file
FILE *cur_fh; ///< current file handle
FILE *handles[MAX_HANDLES]; ///< array of file handles we can have open
byte buffer_start[FIO_BUFFER_SIZE]; ///< local buffer when read from file
#if defined(LIMITED_FDS)
uint open_handles; ///< current amount of open handles
const char *filename[MAX_HANDLES]; ///< array of filenames we (should) have open
uint usage_count[MAX_HANDLES]; ///< count how many times this file has been opened
#endif /* LIMITED_FDS */
} Fio;
static Fio _fio;
/* Get current position in file */
uint32 FioGetPos(void)
{
return _fio.pos + (_fio.buffer - _fio.buffer_start) - FIO_BUFFER_SIZE;
}
void FioSeekTo(uint32 pos, int mode)
{
if (mode == SEEK_CUR) pos += FioGetPos();
_fio.buffer = _fio.buffer_end = _fio.buffer_start + FIO_BUFFER_SIZE;
_fio.pos = pos;
fseek(_fio.cur_fh, _fio.pos, SEEK_SET);
}
#if defined(LIMITED_FDS)
static void FioRestoreFile(int slot)
{
/* Do we still have the file open, or should we reopen it? */
if (_fio.handles[slot] == NULL) {
DEBUG(misc, 6, "Restoring file '%s' in slot '%d' from disk", _fio.filename[slot], slot);
FioOpenFile(slot, _fio.filename[slot]);
}
_fio.usage_count[slot]++;
}
#endif /* LIMITED_FDS */
/* Seek to a file and a position */
void FioSeekToFile(uint32 pos)
{
FILE *f;
#if defined(LIMITED_FDS)
/* Make sure we have this file open */
FioRestoreFile(pos >> 24);
#endif /* LIMITED_FDS */
f = _fio.handles[pos >> 24];
assert(f != NULL);
_fio.cur_fh = f;
FioSeekTo(GB(pos, 0, 24), SEEK_SET);
}
byte FioReadByte(void)
{
if (_fio.buffer == _fio.buffer_end) {
_fio.pos += FIO_BUFFER_SIZE;
fread(_fio.buffer = _fio.buffer_start, 1, FIO_BUFFER_SIZE, _fio.cur_fh);
}
return *_fio.buffer++;
}
void FioSkipBytes(int n)
{
for (;;) {
int m = min(_fio.buffer_end - _fio.buffer, n);
_fio.buffer += m;
n -= m;
if (n == 0) break;
FioReadByte();
n--;
}
}
uint16 FioReadWord(void)
{
byte b = FioReadByte();
return (FioReadByte() << 8) | b;
}
uint32 FioReadDword(void)
{
uint b = FioReadWord();
return (FioReadWord() << 16) | b;
}
void FioReadBlock(void *ptr, uint size)
{
FioSeekTo(FioGetPos(), SEEK_SET);
_fio.pos += size;
fread(ptr, 1, size, _fio.cur_fh);
}
static inline void FioCloseFile(int slot)
{
if (_fio.handles[slot] != NULL) {
fclose(_fio.handles[slot]);
_fio.handles[slot] = NULL;
#if defined(LIMITED_FDS)
_fio.open_handles--;
#endif /* LIMITED_FDS */
}
}
void FioCloseAll(void)
{
int i;
for (i = 0; i != lengthof(_fio.handles); i++)
FioCloseFile(i);
}
bool FioCheckFileExists(const char *filename)
{
FILE *f = FioFOpenFile(filename);
if (f == NULL) return false;
fclose(f);
return true;
}
#if defined(LIMITED_FDS)
static void FioFreeHandle()
{
/* If we are about to open a file that will exceed the limit, close a file */
if (_fio.open_handles + 1 == LIMITED_FDS) {
uint i, count;
int slot;
count = UINT_MAX;
slot = -1;
/* Find the file that is used the least */
for (i = 0; i < lengthof(_fio.handles); i++) {
if (_fio.handles[i] != NULL && _fio.usage_count[i] < count) {
count = _fio.usage_count[i];
slot = i;
}
}
assert(slot != -1);
DEBUG(misc, 6, "Closing filehandler '%s' in slot '%d' because of fd-limit", _fio.filename[slot], slot);
FioCloseFile(slot);
}
}
#endif /* LIMITED_FDS */
FILE *FioFOpenFile(const char *filename)
{
FILE *f;
char buf[MAX_PATH];
snprintf(buf, lengthof(buf), "%s%s", _paths.data_dir, filename);
f = fopen(buf, "rb");
#if !defined(WIN32)
if (f == NULL) {
strtolower(buf + strlen(_paths.data_dir) - 1);
f = fopen(buf, "rb");
#if defined SECOND_DATA_DIR
/* tries in the 2nd data directory */
if (f == NULL) {
snprintf(buf, lengthof(buf), "%s%s", _paths.second_data_dir, filename);
strtolower(buf + strlen(_paths.second_data_dir) - 1);
f = fopen(buf, "rb");
}
#endif
}
#endif
return f;
}
void FioOpenFile(int slot, const char *filename)
{
FILE *f;
#if defined(LIMITED_FDS)
FioFreeHandle();
#endif /* LIMITED_FDS */
f = FioFOpenFile(filename);
if (f == NULL) error("Cannot open file '%s%s'", _paths.data_dir, filename);
FioCloseFile(slot); // if file was opened before, close it
_fio.handles[slot] = f;
#if defined(LIMITED_FDS)
_fio.filename[slot] = filename;
_fio.usage_count[slot] = 0;
_fio.open_handles++;
#endif /* LIMITED_FDS */
FioSeekToFile(slot << 24);
}
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