Provide buffered fread(3)

In order to reduce calls to seek(2) (which are very expensive), this
commit keeps a sector-sized cache for each available FILE instance,
except from the standard streams, of course.

As expected, this allows calls to fread(3) to react much faster when
small, contiguous chunks are read.

1 files changed, 7 insertions, 1 deletions

diff --git a/libpsx/include/stdio.h b/libpsx/include/stdio.h
index 456a438..89d8817 100644
--- a/libpsx/include/stdio.h
+++ b/libpsx/include/stdio.h
@@ -70,6 +70,12 @@ typedef struct
 	unsigned int eof;
 	/** Error marker */
 	unsigned int error;
+	/** Sector buffer. */
+	unsigned char *const buf;
+	/** Last used sector for reading. */
+	size_t last_sect;
+	/** Sector buffer can be used for reading. */
+	unsigned int cache_available;
 }FILE;
 
 extern FILE *const stdin, *const stdout, *const stderr;
@@ -111,7 +117,7 @@ int vprintf(const char *fmt, va_list ap);
 FILE *fdopen(int fildes, const char *mode);
 FILE *fopen(const char *path, const char *mode);
 int fclose(FILE *stream);
-int fread(void *ptr, int size, int nmemb, FILE *f);
+size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream);
 size_t fwrite(void *ptr, size_t size, size_t nmemb, FILE *stream);
 
 int fgetc(FILE *f);