C: phone-number + new GNUmakefile

c/phone-number/src/phone_number.c

@@ -0,0 +1,79 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <malloc.h>
+#include <string.h>
+#include <stdint.h>
+
+#include "phone_number.h"
+
+#define LEN_NUM   10
+#define LPAREN    '('
+
+/* this version is likely not very stable, due to poor scanf() capabilities
+ * I made it to offer an option to traditional strtok() of manual string
+ * parsing.
+ */
+char *phone_number_clean(const char *input)
+{
+    char *scan="%m[+(0-9]%*[()-. ]%m[0-9]%*[()-. ]%m[0-9]%*[-. ]%m[0-9]";
+    char *sn[4];
+    int64_t num[4];
+    int64_t *p = &num[0];
+    int nmatch;
+    char *res;
+
+    if (!(res = malloc(LEN_NUM+1)))
+        return NULL;
+    memset(res, '0', LEN_NUM);
+    *(res+LEN_NUM) = 0;
+
+    nmatch = sscanf(input, scan, &sn[0], &sn[1], &sn[2], &sn[3]);
+
+    for (int i=0; i<nmatch; ++i) {
+        num[i] = atol(*sn[i] == LPAREN? sn[i]+1: sn[i]);
+        free(sn[i]);
+    }
+
+    switch (nmatch) {
+        case 2:
+        case 0:
+            return res;
+        case 1:
+            if (num[0] > 10000000000)
+                num[0] -= 10000000000;
+            if (num[0] > 9999999999 || num[0] < 2000000000)
+                return res;
+            break;
+        case 4:                                   /* area */
+            if (num[0] != 1)
+                return res;
+            p++;
+            fallthrough;
+        case 3:                                   /* last 3 numbers */
+            if (p[0] < 200 || p[0] > 999 || p[1] < 200 || p[1] > 999 ||
+                p[2] < 0 || p[2] > 9999)
+                return res;
+            break;
+    }
+    snprintf(res, LEN_NUM+1, "%ld%ld%ld", *p, *(p+1), *(p+2));
+
+    return res;
+}
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+int main(int ac, char **av)
+{
+    int arg;
+    char *res;
+
+    for (arg=1; arg<ac; ++arg) {
+        res=phone_number_clean(av[arg]);
+        printf("orig = [%s]\n", av[arg]);
+        printf("\t-> [%s]\n", res);
+        free(res);
+    }
+}
+#endif