implement [v]swprintf

[musl] / src / stdio / vswprintf.c

diff --git a/src/stdio/vswprintf.c b/src/stdio/vswprintf.c
new file mode 100644 (file)
index 0000000..4ad581f
--- /dev/null
+++ b/src/stdio/vswprintf.c
@@ -0,0 +1,46 @@
+#include "stdio_impl.h"
+
+struct cookie {
+       wchar_t *ws;
+       size_t l;
+};
+
+static size_t sw_write(FILE *f, const unsigned char *s, size_t l)
+{
+       size_t l0 = l;
+       int i = 0;
+       struct cookie *c = f->cookie;
+       while (c->l && l && (i=mbtowc(c->ws, s, l))>=0) {
+               s+=i;
+               l-=i;
+               c->l--;
+               c->ws++;
+       }
+       *c->ws = 0;
+       return i<0 ? i : l0;
+}
+
+int vswprintf(wchar_t *s, size_t n, const wchar_t *fmt, va_list ap)
+{
+       int r;
+       FILE f;
+       unsigned char buf[256];
+       struct cookie c = { s, n-1 };
+
+       memset(&f, 0, sizeof(FILE));
+       f.lbf = EOF;
+       f.write = sw_write;
+       f.buf_size = sizeof buf;
+       f.buf = buf;
+       f.owner = -1;
+       f.cookie = &c;
+       if (!n) {
+               return -1;
+       } else if (n > INT_MAX) {
+               errno = EOVERFLOW;
+               return -1;
+       }
+       r = vfwprintf(&f, fmt, ap);
+       __oflow(&f);
+       return r>=n ? -1 : r;
+}