mirror of https://github.com/OpenTTD/OpenTTD
(svn r8647) -Codechange: add a general way to handle platforms who can only have a limited amount of file-descripters open at any given time.
The Fios keeps track how many times a file is opened, and tries to close up files which aren't used often. The first platform using this is PSP. Patch based on the work of Turulo.release/0.6
truelight
parent
424001168d
commit
7cd68b5a07
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@ -7,19 +7,26 @@
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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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#include "debug.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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#define MAX_HANDLES 64
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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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FILE *handles[MAX_HANDLES]; ///< 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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#if defined(LIMITED_FDS)
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uint open_handles; ///< current amount of open handles
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const char *filename[MAX_HANDLES]; ///< array of filenames we (should) have open
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uint usage_count[MAX_HANDLES]; ///< count how many times this file has been opened
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#endif /* LIMITED_FDS */
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} Fio;
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static Fio _fio;
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@ -38,10 +45,27 @@ void FioSeekTo(uint32 pos, int mode)
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fseek(_fio.cur_fh, _fio.pos, SEEK_SET);
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}
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#if defined(LIMITED_FDS)
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static void FioRestoreFile(int slot)
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{
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/* Do we still have the file open, or should we reopen it? */
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if (_fio.handles[slot] == NULL) {
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DEBUG(misc, 6, "Restoring file '%s' in slot '%d' from disk", _fio.filename[slot], slot);
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FioOpenFile(slot, _fio.filename[slot]);
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}
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_fio.usage_count[slot]++;
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}
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#endif /* LIMITED_FDS */
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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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FILE *f;
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#if defined(LIMITED_FDS)
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/* Make sure we have this file open */
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FioRestoreFile(pos >> 24);
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#endif /* LIMITED_FDS */
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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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@ -92,6 +116,9 @@ static inline void FioCloseFile(int slot)
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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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#if defined(LIMITED_FDS)
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_fio.open_handles--;
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#endif /* LIMITED_FDS */
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}
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}
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@ -112,6 +139,30 @@ bool FioCheckFileExists(const char *filename)
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return true;
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}
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#if defined(LIMITED_FDS)
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static void FioFreeHandle()
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{
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/* If we are about to open a file that will exceed the limit, close a file */
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if (_fio.open_handles + 1 == LIMITED_FDS) {
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uint i, count;
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int slot;
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count = UINT_MAX;
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slot = -1;
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/* Find the file that is used the least */
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for (i = 0; i < lengthof(_fio.handles); i++) {
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if (_fio.handles[i] != NULL && _fio.usage_count[i] < count) {
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count = _fio.usage_count[i];
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slot = i;
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}
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}
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assert(slot != -1);
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DEBUG(misc, 6, "Closing filehandler '%s' in slot '%d' because of fd-limit", _fio.filename[slot], slot);
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FioCloseFile(slot);
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}
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}
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#endif /* LIMITED_FDS */
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FILE *FioFOpenFile(const char *filename)
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{
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FILE *f;
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@ -141,11 +192,20 @@ FILE *FioFOpenFile(const char *filename)
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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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FILE *f;
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#if defined(LIMITED_FDS)
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FioFreeHandle();
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#endif /* LIMITED_FDS */
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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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#if defined(LIMITED_FDS)
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_fio.filename[slot] = filename;
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_fio.usage_count[slot] = 0;
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_fio.open_handles++;
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#endif /* LIMITED_FDS */
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FioSeekToFile(slot << 24);
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}
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@ -77,6 +77,13 @@
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# define BSWAP16(x) ((x) >> 8 | (x) << 8)
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#endif /* __APPLE__ */
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#if defined(PSP)
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/* PSP can only have 10 file-descriptors open at any given time, but this
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* switch only limits reads via the Fio system. So keep 2 fds free for things
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* like saving a game. */
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#define LIMITED_FDS 8
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#endif /* PSP */
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/* by default we use [] var arrays */
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#define VARARRAY_SIZE
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