152 lines
3.1 KiB
C
152 lines
3.1 KiB
C
/* $Id$ */
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#include "stdafx.h"
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#include "openttd.h"
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#include "fileio.h"
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#include "functions.h"
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#include "string.h"
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#include "macros.h"
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#include "variables.h"
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/*************************************************/
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/* FILE IO ROUTINES ******************************/
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/*************************************************/
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#define FIO_BUFFER_SIZE 512
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typedef struct {
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byte *buffer, *buffer_end; ///< position pointer in local buffer and last valid byte of buffer
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uint32 pos; ///< current (system) position in file
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FILE *cur_fh; ///< current file handle
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FILE *handles[64]; ///< array of file handles we can have open
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byte buffer_start[FIO_BUFFER_SIZE]; ///< local buffer when read from file
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} Fio;
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static Fio _fio;
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// Get current position in file
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uint32 FioGetPos(void)
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{
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return _fio.pos + (_fio.buffer - _fio.buffer_start) - FIO_BUFFER_SIZE;
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}
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void FioSeekTo(uint32 pos, int mode)
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{
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if (mode == SEEK_CUR) pos += FioGetPos();
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_fio.buffer = _fio.buffer_end = _fio.buffer_start + FIO_BUFFER_SIZE;
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_fio.pos = pos;
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fseek(_fio.cur_fh, _fio.pos, SEEK_SET);
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}
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// Seek to a file and a position
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void FioSeekToFile(uint32 pos)
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{
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FILE *f = _fio.handles[pos >> 24];
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assert(f != NULL);
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_fio.cur_fh = f;
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FioSeekTo(GB(pos, 0, 24), SEEK_SET);
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}
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byte FioReadByte(void)
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{
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if (_fio.buffer == _fio.buffer_end) {
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_fio.pos += FIO_BUFFER_SIZE;
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fread(_fio.buffer = _fio.buffer_start, 1, FIO_BUFFER_SIZE, _fio.cur_fh);
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}
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return *_fio.buffer++;
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}
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void FioSkipBytes(int n)
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{
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for (;;) {
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int m = min(_fio.buffer_end - _fio.buffer, n);
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_fio.buffer += m;
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n -= m;
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if (n == 0) break;
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FioReadByte();
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n--;
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}
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}
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uint16 FioReadWord(void)
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{
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byte b = FioReadByte();
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return (FioReadByte() << 8) | b;
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}
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uint32 FioReadDword(void)
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{
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uint b = FioReadWord();
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return (FioReadWord() << 16) | b;
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}
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void FioReadBlock(void *ptr, uint size)
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{
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FioSeekTo(FioGetPos(), SEEK_SET);
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_fio.pos += size;
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fread(ptr, 1, size, _fio.cur_fh);
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}
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static inline void FioCloseFile(int slot)
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{
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if (_fio.handles[slot] != NULL) {
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fclose(_fio.handles[slot]);
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_fio.handles[slot] = NULL;
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}
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}
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void FioCloseAll(void)
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{
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int i;
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for (i = 0; i != lengthof(_fio.handles); i++)
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FioCloseFile(i);
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}
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bool FioCheckFileExists(const char *filename)
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{
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FILE *f = FioFOpenFile(filename);
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if (f == NULL) return false;
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fclose(f);
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return true;
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}
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FILE *FioFOpenFile(const char *filename)
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{
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FILE *f;
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char buf[MAX_PATH];
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snprintf(buf, lengthof(buf), "%s%s", _paths.data_dir, filename);
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f = fopen(buf, "rb");
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#if !defined(WIN32)
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if (f == NULL) {
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strtolower(buf + strlen(_paths.data_dir) - 1);
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f = fopen(buf, "rb");
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#if defined SECOND_DATA_DIR
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// tries in the 2nd data directory
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if (f == NULL) {
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snprintf(buf, lengthof(buf), "%s%s", _paths.second_data_dir, filename);
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strtolower(buf + strlen(_paths.second_data_dir) - 1);
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f = fopen(buf, "rb");
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}
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#endif
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}
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#endif
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return f;
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}
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void FioOpenFile(int slot, const char *filename)
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{
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FILE *f = FioFOpenFile(filename);
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if (f == NULL) error("Cannot open file '%s%s'", _paths.data_dir, filename);
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FioCloseFile(slot); // if file was opened before, close it
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_fio.handles[slot] = f;
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FioSeekToFile(slot << 24);
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}
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