1 files changed, 25 insertions, 0 deletions

diff --git a/nacl/curvecp/hexparse.c b/nacl/curvecp/hexparse.c
new file mode 100644
index 00000000..43bfe044
--- /dev/null
+++ b/nacl/curvecp/hexparse.c
@@ -0,0 +1,25 @@
+#include "hexparse.h"
+
+static int hexdigit(char x)
+{
+  if (x >= '0' && x <= '9') return x - '0';
+  if (x >= 'a' && x <= 'f') return 10 + (x - 'a');
+  if (x >= 'A' && x <= 'F') return 10 + (x - 'A');
+  return -1;
+}
+
+int hexparse(unsigned char *y,long long len,const char *x)
+{
+  if (!x) return 0;
+  while (len > 0) {
+    int digit0;
+    int digit1;
+    digit0 = hexdigit(x[0]); if (digit0 == -1) return 0;
+    digit1 = hexdigit(x[1]); if (digit1 == -1) return 0;
+    *y++ = digit1 + 16 * digit0;
+    --len;
+    x += 2;
+  }
+  if (x[0]) return 0;
+  return 1;
+}