From 3738cc810a8eec0b153d21df160543138d670c5e Mon Sep 17 00:00:00 2001
From: Mattias Andrée <maandree@kth.se>
Date: Mon, 5 Apr 2021 23:47:09 +0200
Subject: Improve number comparsion to handle if only one of the country
 calling codes are specified
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Signed-off-by: Mattias Andrée <maandree@kth.se>
---
 libcontacts_same_number.c | 92 ++++++++++++++++++++++++++++++++---------------
 1 file changed, 63 insertions(+), 29 deletions(-)

diff --git a/libcontacts_same_number.c b/libcontacts_same_number.c
index 633fc7e..cfdcc7c 100644
--- a/libcontacts_same_number.c
+++ b/libcontacts_same_number.c
@@ -19,12 +19,14 @@ static const char *digits[255] = {
 };
 
 static char *
-canonicalise(const char *number, const char *country)
+canonicalise(const char *number, const char *country, char **post_cccp)
 {
 	size_t nlen = 0, clen = 0, skip;
 	const char *digit, *p;
 	char *ret, *r;
 
+	*post_cccp = NULL;
+
 	for (p = number, skip = 0; *p; p++) {
 		digit = digits[*p & 255];
 		if (digit) {
@@ -49,32 +51,35 @@ canonicalise(const char *number, const char *country)
 		}
 	}
 
-	ret = malloc(nlen + clen + 3);
+	r = ret = malloc(nlen + clen + 3);
 	if (!ret)
 		return NULL;
 
-	for (r = ret, p = number, skip = 0; *p; p++) {
-		digit = digits[*p & 255];
-		if (digit) {
-			if (*digit == '(') {
-				skip += 1;
-			} else if (*digit == ')') {
-				skip -= !!skip;
-			} else if (!skip) {
-				*r++ = digit[0];
-				if (digit[1])
-					*r++ = digit[1];
+	if (clen) {
+		for (p = country, skip = 0; *p; p++) {
+			digit = digits[*p & 255];
+			if (digit) {
+				if (*digit == '(') {
+					skip += 1;
+				} else if (*digit == ')') {
+					skip -= !!skip;
+				} else if (!skip) {
+					*r++ = digit[0];
+					if (digit[1])
+						*r++ = digit[1];
+				}
 			}
 		}
+		if (clen < 2 || ret[0] != '0' || ret[1] != '0') {
+			memmove(&ret[2], ret, clen);
+			ret[0] = ret[1] = '0';
+			clen += 2;
+			r += 2;
+		}
+		*post_cccp = r;
 	}
-	*r = '\0';
 
-	if (ret[0] != '0' || ret[1] == '0' || !*country)
-		return ret;
-
-	memmove(&ret[clen], &ret[1], nlen);
-
-	for (r = ret, p = country, skip = 0; *p; p++) {
+	for (p = number, skip = 0; *p; p++) {
 		digit = digits[*p & 255];
 		if (digit) {
 			if (*digit == '(') {
@@ -88,35 +93,64 @@ canonicalise(const char *number, const char *country)
 			}
 		}
 	}
+	*r = '\0';
+
+	if (r[clen] != '0') {
+		*post_cccp = NULL;
+		memmove(ret, &ret[clen], nlen + 1);
+	} else {
+		memmove(&ret[clen], &ret[clen + 1], nlen--);
+		if (nlen >= 2 && ret[clen + 1] == '0') {
+			if (nlen < clen || memcmp(&ret[0], &ret[clen], clen))
+				*post_cccp = NULL;
+			memmove(ret, &ret[clen], nlen + 1);
+		}
+	}
 
-	if (ret[0] == '0' && ret[1] == '0')
-		return ret;
+	if (ret[0] == '0' && ret[1] != '0')
+		*post_cccp = &ret[1];
 
-	memmove(&ret[2], ret, nlen + clen);
-	ret[0] = ret[1] = '0';
 	return ret;
 }
 
 int
 libcontacts_same_number(const char *a, const char *a_country, const char *b, const char *b_country)
 {
-	char *a_full, *b_full;
-	int ret;
+	char *a_full, *b_full, *a_post_ccc, *b_post_ccc;
+	int ret, a_has_ccc, b_has_ccc;
 
 	if (!a || !*a || !b || !*b) {
 		errno = EINVAL;
 		return -1;
 	}
 
-	a_full = canonicalise(a, a_country ? a_country : "");
+	if (!a_country)
+		a_country = "";
+	if (!b_country)
+		b_country = "";
+
+	a_full = canonicalise(a, a_country, &a_post_ccc);
 	if (!a_full)
 		return -1;
-	b_full = canonicalise(b, b_country ? b_country : "");
+	b_full = canonicalise(b, b_country, &b_post_ccc);
 	if (!b_full) {
 		free(a_full);
 		return -1;
 	}
-	ret = !strcmp(a_full, b_full);
+
+	a_has_ccc = (a_full[0] == '0' && a_full[1] == '0');
+	b_has_ccc = (b_full[0] == '0' && b_full[1] == '0');
+
+	a = a_full;
+	b = b_full;
+	if (a_has_ccc != b_has_ccc) {
+		if (a_post_ccc && b_post_ccc) {
+			a = a_post_ccc;
+			b = b_post_ccc;
+		}
+	}
+
+	ret = !strcmp(a, b);
 	free(a_full);
 	free(b_full);
 	return ret;
-- 
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