File diff r5583:398b6d85e7a3 → r5584:545d748cc681
src/fileio.cpp
Show inline comments
 
new file 100644
 
/* $Id$ */
 

	
 
#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", _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 = 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;
 
	FioSeekToFile(slot << 24);
 
}