Add build system scaffolding and libc headers

1 files changed, 50 insertions, 0 deletions

diff --git a/lib/libc/stdio/fread.c b/lib/libc/stdio/fread.c
new file mode 100644
index 00000000..a27b64c4
--- /dev/null
+++ b/lib/libc/stdio/fread.c
@@ -0,0 +1,50 @@
+#include <io.h>
+#include <unistd.h>
+#include <string.h>
+#include <atomic.h>
+#include <stdio.h>
+
+char __stdin_buffer[BUFSIZ];
+
+size_t fread(void *restrict ptr, size_t size, size_t nitems,
+	     FILE *restrict stream)
+{
+	if (size == 0 || nitems == 0)
+		return 0;
+
+	size_t total = size * nitems;
+	size_t bytes_read = 0;
+	char *p = ptr;
+
+	LIBC_LOCK(stream->lock);
+
+	while (total > 0) {
+		if (stream->buf_pos < stream->buf_len) {
+			size_t available = stream->buf_len - stream->buf_pos;
+			size_t to_copy = total < available ? total : available;
+
+			memcpy(p, stream->buf + stream->buf_pos, to_copy);
+			stream->buf_pos += to_copy;
+			p += to_copy;
+			bytes_read += to_copy;
+			total -= to_copy;
+			continue;
+		}
+
+		ssize_t ret = read(stream->fd, stream->buf, stream->buf_size);
+		if (ret <= 0) {
+			if (ret < 0)
+				stream->flags |= _IO_ERR;
+			else
+				stream->flags |= _IO_EOF;
+			break;
+		}
+
+		stream->buf_len = ret;
+		stream->buf_pos = 0;
+	}
+
+	LIBC_UNLOCK(stream->lock);
+
+	return bytes_read / size;
+}