fix base32 mask calculation

base32_from.c

@@ -22,27 +22,33 @@ static const u8 base32f[256] = {
 */
 size_t base32_from(u8 *dst, u8 *dmask, const char *src)
 {
-	int i, j, k = -1, l;
-	u8 mask = 0;
+	int i, j, k = -1, l, sk = 0;
+	u8 mask = 0, cmask = 0;
 	for (i = 0;;i += 5) {
 		j = i/5;
 		l = i%8;
 		if (!src[j]) {
-			if (!l) // workaround: if l==0 mask misses some upper bits
-				mask = 0xFF;
 			if (k >= 0)
-				dst[k] &= mask;
-			//printf("dst[k]:%02X mask:%02X l:%d\n", dst[k], (unsigned int)(mask & 0xFF), l);
-			*dmask = mask;
+				dst[k] &= cmask;
+			//printf("dst[k]:%02X mask:%02X l:%d\n", dst[k], (cmask & 0xFF), l);
+			*dmask = cmask;
 			return (size_t)(k + 1);
 		}
 		k = i/8;
+		if (k != sk)
+			cmask = 0;
+		sk = k;
 		mask = (0x1F << 3) >> l;
+		cmask |= mask;
+		//printf("1:m[%02X] cm[%02X]\n",mask,cmask);
 		dst[k] &= ~mask;
 		dst[k] |= (base32f[(u8)src[j]] << 3) >> l;
 		if (((0x1F << 8) >> (l+5-8)) & 0xFF) {
-			mask = ((0x1F << 8) >> (l+5-8)) & 0xFF;
 			++k;
+			sk = k;
+			mask = ((0x1F << 8) >> (l+5-8)) & 0xFF;
+			cmask = mask;
+			//printf("2:m[%02X] cm[%02X]\n",mask,cmask);
 			dst[k] &= ~mask;
 			dst[k] |= ((base32f[(u8)src[j]] << 8) >> (l+5-8)) & 0xFF;
 		}

main.c

@@ -75,6 +75,7 @@ static void filters_add(const char *filter)
 	size_t ret;
 
 	ret = base32_from(buf,&bf.mask,filter);
+	//printf("--m:%02X\n", bf.mask);
 	if (!ret)
 		return;
 	bf.f = malloc(ret);
@@ -113,13 +114,15 @@ static void loadfilterfile(const char *fname)
 static void printfilters()
 {
 	fprintf(stderr, "current filters:\n");
+#if 0
 	for (size_t i = 0; i < VEC_LENGTH(filters); ++i) {
 		fprintf(stderr, "\t%s\n", VEC_BUF(filters, i).str);
 	}
+#endif
 	for (size_t i = 0; i < VEC_LENGTH(bfilters); ++i) {
 		char buf[256];
-		base32_to(buf, VEC_BUF(bfilters, i).f, VEC_BUF(bfilters, i).len);
-		fprintf(stderr, "\t%s\n", buf);
+		base32_to(buf,VEC_BUF(bfilters,i).f,VEC_BUF(bfilters,i).len);
+		fprintf(stderr, "\t%s [%02X]\n",buf,VEC_BUF(bfilters,i).mask);
 	}
 }
 

test_base32.c

@@ -21,6 +21,42 @@ struct texttestcase {
 	{"foobar", "mzxw6ytboi", "foobar"},
 };
 
+/*
+r:0, mask:FF
+ -- 
+r:2, mask:C0
+f -- f
+r:3, mask:F0
+fo -- fo
+r:4, mask:80
+foo -- foo
+r:5, mask:E0
+foob -- foob
+r:5, mask:FF
+fooba -- fooba
+r:7, mask:C0
+foobar -- foobar
+*/
+
+/*
+struct masktestcase {
+	const char *src;
+	u8 mask;
+} tests1[] = {
+	{"", 0x00},
+	{"a", 0x00},
+	{"ab", 0x00},
+	{"abc", 0x00},
+	{"abcd", 0x00},
+	{"abcde", 0x00},
+	{"abcdef", 0x00},
+	{"abcdefg", 0x00},
+	{"abcdefgh", 0x00},
+	{"abcdefghi", 0x00},
+	{"abcdefghij", 0x00},
+};
+*/
+
 int main()
 {
 	char buf[1024], buf2[1024], mask;
@@ -30,6 +66,9 @@ int main()
 		assert(strcmp(buf, tests0[i].out) == 0);
 		r = base32_from((u8 *)buf2, (u8 *)&mask, buf);
 		buf2[r] = 0;
+		if (r > 0) {
+			assert((buf2[r-1] & ~mask) == 0);
+		}
 		//fprintf(stderr, "r:%d, mask:%02X\n", (int)r, ((unsigned int)mask) & 0xFF);
 		//assert(r == strlen(buf2));
 		//assert(r == strlen(tests0[i].rev));