libioutil Implement a file reader

libioutil/filereader.h

@@ -0,0 +1,33 @@
+#ifndef _LIBIOUTIL_FILEREADER_H
+#define _LIBIOUTIL_FILEREADER_H
+
+#include <path_defs.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#define FR_OK                0
+#define FR_VOLUME_OPEN_ERROR 1
+#define FR_DESC_ERROR        2
+#define FR_NOT_FILE          3
+#define FR_VOLUME_NOT_OPENED 4
+#define FR_READ_ERROR        5
+#define FR_CURSOR_OOB        6
+
+#define FR_OPEN (1 << 31)
+
+struct filereader {
+  char volume[VOLUME_MAX];
+  char path[PATH_MAX];
+  size_t read_cursor;
+  size_t file_size;
+  uint32_t flags;
+};
+
+int filereader_init (struct filereader* fw, const char* volume, const char* path);
+
+int filereader_fini (struct filereader* fw);
+
+int filereader_read (struct filereader* fw, uint8_t* buffer, size_t buffer_size);
+
+#endif // _LIBIOUTIL_FILEREADER_H