Add mbio.h and freadrune()

3 files changed, 40 insertions, 0 deletions

diff --git a/README b/README
index 43a62c6..e8c87cd 100644
--- a/README
+++ b/README
@@ -14,6 +14,7 @@ The headers as of now are:
  • dynarr.h — dynamic array implementation
  • errors.h — err.h-inspired diagnostics functions
  • macros.h — miscellaneous utility macros (MIN/MAX/lengthof/etc.)
+ • mbio.h — multibyte file I/O
  • mbstring.h — multibyte-strings
  • optparse.h — option parsing functions
  • rune.h — inttypes.h but for runes
diff --git a/include/mbio.h b/include/mbio.h
new file mode 100644
index 0000000..ef2fcd5
--- /dev/null
+++ b/include/mbio.h
@@ -0,0 +1,16 @@
+#ifndef MLIB_MBIOO_H
+#define MLIB_MBIOO_H
+
+#include <stdio.h>
+
+#include "__charN_t.h"
+#include "__rune.h"
+
+typedef struct {
+	char8_t _buf[4];
+	int _fill;
+} u8_io_state;
+
+int freadrune(rune *, u8_io_state *, FILE *);
+
+#endif /* !MLIB_MBIOO_H */
diff --git a/lib/mbio/freadrune.c b/lib/mbio/freadrune.c
new file mode 100644
index 0000000..efa42b3
--- /dev/null
+++ b/lib/mbio/freadrune.c
@@ -0,0 +1,23 @@
+#include <macros.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "mbio.h"
+#include "mbstring.h"
+
+int
+freadrune(rune *ch, u8_io_state *st, FILE *stream)
+{
+	size_t n, need;
+	need = lengthof(st->_buf) - st->_fill;
+	st->_fill += n = fread(st->_buf + st->_fill, 1, need, stream);
+	if (n < need && ferror(stream))
+		return -1;
+	if (st->_fill == 0)
+		return 0;
+
+	int w = u8tor(ch, st->_buf);
+	memmove(st->_buf, st->_buf + w, lengthof(st->_buf) - w);
+	st->_fill -= w;
+	return w;
+}