1 files changed, 59 insertions, 0 deletions
diff --git a/src/libc/stdio.c b/src/libc/stdio.c
new file mode 100644
index 0000000..8bbbe9a
--- /dev/null
+++ b/src/libc/stdio.c
@@ -0,0 +1,59 @@
+#include <u.h>
+#include <libc.h>
+
+int
+printf(byte* fmt, ...)
+{
+    va_list args;
+    va_start(args, fmt);
+
+    int nw, rem, peek, len;
+    byte *str, c;
+
+    while (*fmt) {
+        rem = INT_MAX - nw;
+
+        if (fmt[0] != '%' || fmt[1] == '%') {
+            if (fmt[0] == '%') fmt++;
+
+            for (peek = 1; fmt[peek] && fmt[peek] != '%'; peek++) {
+                ;
+            }
+            if (rem < peek) return -1;
+            // TODO: Print here.
+            fmt += peek;
+            nw  += peek;
+            continue;
+        }
+
+        str = fmt++;
+
+        switch (*fmt++) {
+        case 'c':
+            c = va_arg(args, int);
+            if (rem < 0) return -1;
+            // TODO: Print here
+            nw++;
+            break;
+
+        case 's':
+            str = va_arg(args, byte*);
+            len = strlen(str);
+            if (rem < len) return -1;
+            // TODO: Print here
+            nw += len;
+            break;
+        default:
+            fmt = str;
+            len = strlen(fmt);
+            if (rem < len) return -1;
+            // TODO: Print here
+            nw += len;
+            fmt += len;
+            break;
+        }
+    }
+
+    va_end(args);
+    return nw;
+}