OpenTTD-patches/fileio.c

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/* $Id$ */
#include "stdafx.h"
#include "openttd.h"
#include "fileio.h"
#include "functions.h"
#include "string.h"
#include "macros.h"
#include "variables.h"
/*************************************************/
/* FILE IO ROUTINES ******************************/
/*************************************************/
#define FIO_BUFFER_SIZE 512
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[64]; ///< array of file handles we can have open
byte buffer_start[FIO_BUFFER_SIZE]; ///< local buffer when read from file
} 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);
}
// Seek to a file and a position
void FioSeekToFile(uint32 pos)
{
FILE *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;
}
}
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;
}
FILE *FioFOpenFile(const char *filename)
{
FILE *f;
char buf[MAX_PATH];
snprintf(buf, lengthof(buf), "%s%s", _path.data_dir, filename);
f = fopen(buf, "rb");
#if !defined(WIN32)
if (f == NULL) {
strtolower(buf + strlen(_path.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", _path.second_data_dir, filename);
strtolower(buf + strlen(_path.second_data_dir) - 1);
f = fopen(buf, "rb");
}
#endif
}
#endif
return f;
}
void FioOpenFile(int slot, const char *filename)
{
FILE *f = FioFOpenFile(filename);
if (f == NULL) error("Cannot open file '%s%s'", _path.data_dir, filename);
FioCloseFile(slot); // if file was opened before, close it
_fio.handles[slot] = f;
FioSeekToFile(slot << 24);
}