1 /* $Id$ */

     2 

     3 #include "stdafx.h"

     4 #include "openttd.h"

     5 #include "fileio.h"

     6 #include "functions.h"

     7 #include "string.h"

     8 #include "macros.h"

     9 #include "variables.h"

    10 

    11 /*************************************************/

    12 /* FILE IO ROUTINES ******************************/

    13 /*************************************************/

    14 

    15 #define FIO_BUFFER_SIZE 512

    16 

    17 typedef struct {

    18 	byte *buffer, *buffer_end;          ///< position pointer in local buffer and last valid byte of buffer

    19 	uint32 pos;                         ///< current (system) position in file

    20 	FILE *cur_fh;                       ///< current file handle

    21 	FILE *handles[64];                  ///< array of file handles we can have open

    22 	byte buffer_start[FIO_BUFFER_SIZE]; ///< local buffer when read from file

    23 } Fio;

    24 

    25 static Fio _fio;

    26 

    27 // Get current position in file

    28 uint32 FioGetPos(void)

    29 {

    30 	return _fio.pos + (_fio.buffer - _fio.buffer_start) - FIO_BUFFER_SIZE;

    31 }

    32 

    33 void FioSeekTo(uint32 pos, int mode)

    34 {

    35 	if (mode == SEEK_CUR) pos += FioGetPos();

    36 	_fio.buffer = _fio.buffer_end = _fio.buffer_start + FIO_BUFFER_SIZE;

    37 	_fio.pos = pos;

    38 	fseek(_fio.cur_fh, _fio.pos, SEEK_SET);

    39 }

    40 

    41 // Seek to a file and a position

    42 void FioSeekToFile(uint32 pos)

    43 {

    44 	FILE *f = _fio.handles[pos >> 24];

    45 	assert(f != NULL);

    46 	_fio.cur_fh = f;

    47 	FioSeekTo(GB(pos, 0, 24), SEEK_SET);

    48 }

    49 

    50 byte FioReadByte(void)

    51 {

    52 	if (_fio.buffer == _fio.buffer_end) {

    53 		_fio.pos += FIO_BUFFER_SIZE;

    54 		fread(_fio.buffer = _fio.buffer_start, 1, FIO_BUFFER_SIZE, _fio.cur_fh);

    55 	}

    56 	return *_fio.buffer++;

    57 }

    58 

    59 void FioSkipBytes(int n)

    60 {

    61 	for (;;) {

    62 		int m = min(_fio.buffer_end - _fio.buffer, n);

    63 		_fio.buffer += m;

    64 		n -= m;

    65 		if (n == 0) break;

    66 		FioReadByte();

    67 		n--;

    68 	}

    69 }

    70 

    71 uint16 FioReadWord(void)

    72 {

    73 	byte b = FioReadByte();

    74 	return (FioReadByte() << 8) | b;

    75 }

    76 

    77 uint32 FioReadDword(void)

    78 {

    79 	uint b = FioReadWord();

    80 	return (FioReadWord() << 16) | b;

    81 }

    82 

    83 void FioReadBlock(void *ptr, uint size)

    84 {

    85 	FioSeekTo(FioGetPos(), SEEK_SET);

    86 	_fio.pos += size;

    87 	fread(ptr, 1, size, _fio.cur_fh);

    88 }

    89 

    90 static inline void FioCloseFile(int slot)

    91 {

    92 	if (_fio.handles[slot] != NULL) {

    93 		fclose(_fio.handles[slot]);

    94 		_fio.handles[slot] = NULL;

    95 	}

    96 }

    97 

    98 void FioCloseAll(void)

    99 {

   100 	int i;

   101 

   102 	for (i = 0; i != lengthof(_fio.handles); i++)

   103 		FioCloseFile(i);

   104 }

   105 

   106 bool FioCheckFileExists(const char *filename)

   107 {

   108 	FILE *f = FioFOpenFile(filename);

   109 	if (f == NULL) return false;

   110 

   111 	fclose(f);

   112 	return true;

   113 }

   114 

   115 FILE *FioFOpenFile(const char *filename)

   116 {

   117 	FILE *f;

   118 	char buf[MAX_PATH];

   119 

   120 	snprintf(buf, lengthof(buf), "%s%s", _paths.data_dir, filename);

   121 

   122 	f = fopen(buf, "rb");

   123 #if !defined(WIN32)

   124 	if (f == NULL) {

   125 		strtolower(buf + strlen(_paths.data_dir) - 1);

   126 		f = fopen(buf, "rb");

   127 

   128 #if defined SECOND_DATA_DIR

   129 		// tries in the 2nd data directory

   130 		if (f == NULL) {

   131 			snprintf(buf, lengthof(buf), "%s%s", _paths.second_data_dir, filename);

   132 			strtolower(buf + strlen(_paths.second_data_dir) - 1);

   133 			f = fopen(buf, "rb");

   134 		}

   135 #endif

   136 	}

   137 #endif

   138 

   139 	return f;

   140 }

   141 

   142 void FioOpenFile(int slot, const char *filename)

   143 {

   144 	FILE *f = FioFOpenFile(filename);

   145 

   146 	if (f == NULL) error("Cannot open file '%s%s'", _paths.data_dir, filename);

   147 

   148 	FioCloseFile(slot); // if file was opened before, close it

   149 	_fio.handles[slot] = f;

   150 	FioSeekToFile(slot << 24);

   151 }