Initial import

libc/fmt/vsscanf.h

@@ -0,0 +1,39 @@
+#ifndef COSMOPOLITAN_LIBC_INTERNAL_VSSCANF_H_
+#define COSMOPOLITAN_LIBC_INTERNAL_VSSCANF_H_
+#include "libc/fmt/fmt.h"
+#include "libc/fmt/vcscanf.h"
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+
+struct StringScannerState {
+  const unsigned char *s;
+  size_t i;
+};
+
+static inline int vsscanfcb(void *arg) {
+  struct StringScannerState *state = arg;
+  int res;
+  if ((res = state->s[state->i])) {
+    state->i++;
+  } else {
+    res = -1;
+  }
+  return res;
+}
+
+/**
+ * String decoder builder.
+ *
+ * This macro grants sscanf() and vsscanf() the choice to either link or
+ * inline the full vcscanf() implementation.
+ *
+ * @see libc/fmt/vcscanf.h (for docs and implementation)
+ */
+static inline int __vsscanf(const char *str, const char *fmt, va_list ap,
+                            int impl(int callback(void *), void *arg,
+                                     const char *fmt, va_list ap)) {
+  struct StringScannerState state = {(const unsigned char *)str, 0};
+  return impl(vsscanfcb, &state, fmt, ap);
+}
+
+#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
+#endif /* COSMOPOLITAN_LIBC_INTERNAL_VSSCANF_H_ */