blob: base64 encoding and decoding

and prefer sha1 checksums to be stored in base64 encoded format.

2 files changed, 129 insertions, 17 deletions

diff --git a/src/apk_blob.h b/src/apk_blob.h
index 170cf20..398056a 100644
--- a/src/apk_blob.h
+++ b/src/apk_blob.h
@@ -92,11 +92,13 @@ static inline const int apk_checksum_compare(const struct apk_checksum *a,
 void apk_blob_push_blob(apk_blob_t *to, apk_blob_t literal);
 void apk_blob_push_uint(apk_blob_t *to, unsigned int value, int radix);
 void apk_blob_push_csum(apk_blob_t *to, struct apk_checksum *csum);
+void apk_blob_push_base64(apk_blob_t *to, apk_blob_t binary);
 void apk_blob_push_hexdump(apk_blob_t *to, apk_blob_t binary);
 
 void apk_blob_pull_char(apk_blob_t *b, int expected);
 unsigned int apk_blob_pull_uint(apk_blob_t *b, int radix);
 void apk_blob_pull_csum(apk_blob_t *b, struct apk_checksum *csum);
+void apk_blob_pull_base64(apk_blob_t *b, apk_blob_t to);
 void apk_blob_pull_hexdump(apk_blob_t *b, apk_blob_t to);
 
 #endif
diff --git a/src/blob.c b/src/blob.c
index ed7f418..0b6efbf 100644
--- a/src/blob.c
+++ b/src/blob.c
@@ -186,14 +186,6 @@ void apk_blob_push_uint(apk_blob_t *to, unsigned int value, int radix)
 	apk_blob_push_blob(to, APK_BLOB_PTR_PTR(ptr+1, &buf[sizeof(buf)-1]));
 }
 
-static int checksum_char_to_id(char chr)
-{
-	switch (chr) {
-	case '1': return APK_CHECKSUM_SHA1;
-	}
-	return APK_CHECKSUM_NONE;
-}
-
 void apk_blob_push_csum(apk_blob_t *to, struct apk_checksum *csum)
 {
 	switch (csum->type) {
@@ -201,8 +193,8 @@ void apk_blob_push_csum(apk_blob_t *to, struct apk_checksum *csum)
 		apk_blob_push_hexdump(to, APK_BLOB_CSUM(*csum));
 		break;
 	case APK_CHECKSUM_SHA1:
-		apk_blob_push_blob(to, APK_BLOB_STR("X1"));
-		apk_blob_push_hexdump(to, APK_BLOB_CSUM(*csum));
+		apk_blob_push_blob(to, APK_BLOB_STR("Q1"));
+		apk_blob_push_base64(to, APK_BLOB_CSUM(*csum));
 		break;
 	default:
 		*to = APK_BLOB_NULL;
@@ -231,6 +223,42 @@ void apk_blob_push_hexdump(apk_blob_t *to, apk_blob_t binary)
 	to->len -= binary.len * 2;
 }
 
+static const char b64encode[] =
+	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+static inline void push_b64_chunk(unsigned char *to, const unsigned char *from, int len)
+{
+	to[0] = b64encode[from[0] >> 2];
+	to[1] = b64encode[((from[0] & 0x03) << 4) | ((from[1] & 0xf0) >> 4)];
+	to[2] = len < 2 ? '=' : b64encode[((from[1] & 0x0f) << 2) |
+	                                  ((from[2] & 0xc0) >> 6)];
+	to[3] = len < 3 ? '=' : b64encode[from[2] & 0x3f ];
+}
+
+void apk_blob_push_base64(apk_blob_t *to, apk_blob_t binary)
+{
+	unsigned char *src = (unsigned char *) binary.ptr;
+	unsigned char *dst = (unsigned char *) to->ptr;
+	int i, needed;
+
+	if (unlikely(APK_BLOB_IS_NULL(*to)))
+		return;
+
+	needed = ((binary.len + 2) / 3) * 4;
+	if (unlikely(to->len < needed)) {
+		*to = APK_BLOB_NULL;
+		return;
+	}
+
+	for (i = 0; i < binary.len / 3; i++, src += 3, dst += 4)
+		push_b64_chunk(dst, src, 4);
+	i = binary.len % 3;
+	if (i != 0)
+		push_b64_chunk(dst, src, i);
+	to->ptr += needed;
+	to->len -= needed;
+}
+
 void apk_blob_pull_char(apk_blob_t *b, int expected)
 {
 	if (unlikely(APK_BLOB_IS_NULL(*b)))
@@ -265,6 +293,8 @@ unsigned int apk_blob_pull_uint(apk_blob_t *b, int radix)
 
 void apk_blob_pull_csum(apk_blob_t *b, struct apk_checksum *csum)
 {
+	int encoding;
+
 	if (unlikely(APK_BLOB_IS_NULL(*b)))
 		return;
 
@@ -273,18 +303,35 @@ void apk_blob_pull_csum(apk_blob_t *b, struct apk_checksum *csum)
 		return;
 	}
 
-	switch (b->ptr[0]) {
-	case 'X':
-		csum->type = checksum_char_to_id(b->ptr[1]);
-		b->ptr += 2;
-		b->len -= 2;
+	if (dx(b->ptr[0]) != -1) {
+		/* Assume MD5 for backwards compatibility */
+		csum->type = APK_CHECKSUM_MD5;
 		apk_blob_pull_hexdump(b, APK_BLOB_CSUM(*csum));
+		return;
+	}
+
+	encoding = b->ptr[0];
+	switch (b->ptr[1]) {
+	case '1':
+		csum->type = APK_CHECKSUM_SHA1;
 		break;
 	default:
-		/* Assume MD5 for backwards compatibility */
-		csum->type = APK_CHECKSUM_MD5;
+		*b = APK_BLOB_NULL;
+		return;
+	}
+	b->ptr += 2;
+	b->len -= 2;
+
+	switch (encoding) {
+	case 'X':
 		apk_blob_pull_hexdump(b, APK_BLOB_CSUM(*csum));
 		break;
+	case 'Q':
+		apk_blob_pull_base64(b, APK_BLOB_CSUM(*csum));
+		break;
+	default:
+		*b = APK_BLOB_NULL;
+		break;
 	}
 }
 
@@ -314,3 +361,66 @@ void apk_blob_pull_hexdump(apk_blob_t *b, apk_blob_t to)
 err:
 	*b = APK_BLOB_NULL;
 }
+
+static unsigned char b64decode[] = {
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x3e, 0xff, 0xff, 0xff, 0x3f,
+	0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0xff, 0xff,
+	0xff, 0x00, 0xff, 0xff, 0xff, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
+	0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12,
+	0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, 0x24,
+	0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30,
+	0x31, 0x32, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff
+};
+
+static inline int pull_b64_chunk(unsigned char *to, const unsigned char *from, int len)
+{
+	unsigned char tmp[4];
+	int i;
+
+	for (i = 0; i < 4; i++) {
+		if (unlikely(from[i] >= 0x80))
+			return -1;
+		tmp[i] = b64decode[from[i]];
+		if (unlikely(tmp[i] == 0xff))
+			return -1;
+	}
+
+	to[0] = (tmp[0] << 2 | tmp[1] >> 4);
+	if (len > 1)
+		to[1] = (tmp[1] << 4 | tmp[2] >> 2);
+	else if (unlikely(from[2] != '='))
+		return -1;
+	if (len > 2)
+		to[2] = (((tmp[2] << 6) & 0xc0) | tmp[3]);
+	else if (unlikely(from[3] != '='))
+		return -1;
+	return 0;
+}
+
+void apk_blob_pull_base64(apk_blob_t *b, apk_blob_t to)
+{
+	unsigned char *src = (unsigned char *) b->ptr;
+	unsigned char *dst = (unsigned char *) to.ptr;
+	int i, needed;
+
+	if (unlikely(APK_BLOB_IS_NULL(*b)))
+		return;
+
+	needed = ((to.len + 2) / 3) * 4;
+	if (unlikely(b->len < needed)) {
+		*b = APK_BLOB_NULL;
+		return;
+	}
+
+	for (i = 0; i < to.len / 3; i++, src += 4, dst += 3)
+		pull_b64_chunk(dst, src, 4);
+	i = to.len % 3;
+	if (i != 0)
+		pull_b64_chunk(dst, src, i);
+	b->ptr += needed;
+	b->len -= needed;
+}