1 files changed, 79 insertions, 0 deletions
diff --git a/usr/klibc/stdio/fread.c b/usr/klibc/stdio/fread.c
new file mode 100644
index 0000000..b099426
--- /dev/null
+++ b/usr/klibc/stdio/fread.c
@@ -0,0 +1,79 @@
+/*
+ * fread.c
+ */
+
+#include <stdbool.h>
+#include <string.h>
+#include "stdioint.h"
+
+size_t _fread(void *buf, size_t count, FILE *file)
+{
+	struct _IO_file_pvt *f = stdio_pvt(file);
+	size_t bytes = 0;
+	size_t nb;
+	char *p = buf;
+	char *rdptr;
+	ssize_t rv;
+	bool bypass;
+
+	if (!count)
+		return 0;
+
+	if (f->obytes)		/* User error! */
+		__fflush(f);
+
+	while (count) {
+		while (f->ibytes == 0) {
+			/*
+			 * The buffer is empty, we have to read
+			 */
+			bypass = (count >= f->bufsiz);
+			if (bypass) {
+				/* Large read, bypass buffer */
+				rdptr = p;
+				nb = count;
+			} else {
+				rdptr = f->buf + _IO_UNGET_SLOP;
+				nb = f->bufsiz;
+			}
+
+			rv = read(f->pub._IO_fileno, rdptr, nb);
+			if (rv == -1) {
+				if (errno == EINTR || errno == EAGAIN)
+					continue;
+				f->pub._IO_error = true;
+				return bytes;
+			} else if (rv == 0) {
+				f->pub._IO_eof = true;
+				return bytes;
+
+
+			}
+
+			if (bypass) {
+				p += rv;
+				bytes += rv;
+				count -= rv;
+			} else {
+				f->ibytes = rv;
+				f->data = rdptr;
+			}
+
+			if (!count)
+				return bytes;
+		}
+
+		/* If we get here, the buffer is non-empty */
+		nb = f->ibytes;
+		nb = (count < nb) ? count : nb;
+		if (nb) {
+			memcpy(p, f->data, nb);
+			p += nb;
+			bytes += nb;
+			count -= nb;
+			f->data += nb;
+			f->ibytes -= nb;
+		}
+	}
+	return bytes;
+}