let there be Spain

2 files changed, 129 insertions, 19 deletions

diff --git a/src/reducer/Makefile.am b/src/reducer/Makefile.am
index 5cbe6f7..3b7edb6 100644
--- a/src/reducer/Makefile.am
+++ b/src/reducer/Makefile.am
@@ -22,6 +22,7 @@ libanastasisredux_la_SOURCES = \
   validation_CZ_BN.c \
   validation_DE_SVN.c \
   validation_DE_TIN.c \
+  validation_ES_DNI.c \
   validation_IN_AADHAR.c \
   validation_IT_CF.c \
   validation_XX_SQUARE.c \
diff --git a/src/reducer/validation_ES_DNI.c b/src/reducer/validation_ES_DNI.c
index 06bf143..6679f45 100644
--- a/src/reducer/validation_ES_DNI.c
+++ b/src/reducer/validation_ES_DNI.c
@@ -17,9 +17,75 @@
  * @file reducer/validation_ES_DNI.c
  * @brief validation logic for Spanish Documento Nacional de Identidad numbers, and Número de Identificación de Extranjeros
  * @author Christian Grothoff
+ *
+ * Examples:
+ * 12345678Z, 39740191D, 14741806W, X8095495R
  */
 #include <string.h>
 #include <stdbool.h>
+#include <stdio.h>
+
+/**
+ * Function to validate a Spanish CIF number.
+ *
+ * @param civ number to validate
+ * @return true if validation passed, else false
+ */
+static bool
+validate_cif (const char *cif)
+{
+  size_t slen = strlen (cif);
+  char letter = cif[0];
+  const char *number = &cif[1];
+  char control = cif[slen - 1];
+  unsigned int sum = 0;
+
+  if (9 != slen)
+    return false;
+
+  for (unsigned int i = 0; i < slen - 2; i++)
+  {
+    unsigned int n = number[i] - '0';
+
+    if (n >= 10)
+      return false;
+    if (0 == (i % 2))
+    {
+      n *= 2;
+      sum += n < 10 ? n : n - 9;
+    }
+    else
+    {
+      sum += n;
+    }
+  }
+  sum %= 10;
+  if (0 != sum)
+    sum = 10 - sum;
+  {
+    char control_digit = "0123456789"[sum];
+    char control_letter = "JABCDEFGHI"[sum];
+
+    switch (letter)
+    {
+    case 'A':
+    case 'B':
+    case 'E':
+    case 'H':
+      return control == control_digit;
+    case 'N':
+    case 'P':
+    case 'Q':
+    case 'R':
+    case 'S':
+    case 'W':
+      return control == control_letter;
+    default:
+      return (control == control_letter) ||
+             (control == control_digit);
+    }
+  }
+}
 
 
 /**
@@ -43,32 +109,75 @@ ES_DNI_check (const char *dni_number)
     return false;
   switch (dni_number[0])
   {
+  case 'A':
+  case 'B':
+  case 'C':
+  case 'D':
+  case 'E':
+  case 'F':
+  case 'G':
+  case 'H':
+  case 'I':
+  case 'J':
+  case 'K':
+  case 'L':
+  case 'N':
+  case 'O':
+  case 'P':
+  case 'Q':
+  case 'R':
+  case 'S':
+  case 'T':
+  case 'U':
+  case 'V':
+  case 'W':
+    /* CIF: [A-W]\d{7}[0-9A-J] */
+    /* CIF is for companies, we only take those
+       of individuals here! */
+    return false; /* CIV is not allowed! */
+  case 'M':
+    /* special NIE, with CIF validation (?),
+       but for individuals, see
+       https://www.strongabogados.com/tax-id-spain.php */
+    return validate_cif (dni_number);
   case 'X':
-    fact = 0;
-    dni_number++;
-    break;
   case 'Y':
-    fact = 10000000;
-    dni_number++;
-    break;
   case 'Z':
-    fact = 20000000;
-    dni_number++;
+    /* NIE */
+    fact = dni_number[0] - 'X';
+    /* 7 or 8 digits */
+    if (2 == sscanf (&dni_number[1],
+                     "%8u%c%c",
+                     &num,
+                     &chksum,
+                     &dummy))
+    {
+      num += fact * 100000000;
+    }
+    else if (2 == sscanf (&dni_number[1],
+                          "%7u%c%c",
+                          &num,
+                          &chksum,
+                          &dummy))
+    {
+      num += fact * 10000000;
+    }
+    else
+    {
+      return false;
+    }
     break;
   default:
     fact = 0;
-    /* domestic */
+    /* DNI */
+    if (2 != sscanf (dni_number,
+                     "%8u%c%c",
+                     &num,
+                     &chksum,
+                     &dummy))
+      return false;
+    break;
   }
-
-  if (2 != sscanf (dni_number,
-                   "%7u%c%c"
-                   & num,
-                   &chksum,
-                   &dummy))
-    return false;
-  num += fact;
-  if (map[num % 23] != chksum)
-    return false;
   if (map[num % 23] != chksum)
     return false;
   return true;