4 files changed, 83 insertions, 14 deletions
diff --git a/librsync/librsync.go b/librsync/librsync.go
index 641e480..1ffc7ec 100644
--- a/librsync/librsync.go
+++ b/librsync/librsync.go
@@ -6,6 +6,7 @@ package librsync
 #include <stdio.h>
 #include <librsync.h>
 #include <stdlib.h>
+#include <stdbool.h>
 
 static inline rs_buffers_t* new_rs_buffers() {
 	return (rs_buffers_t*) malloc(sizeof(rs_buffers_t));
@@ -17,6 +18,27 @@ rs_result patchCallback(void* _patcher, rs_long_t pos, size_t* len, void** _buf)
 	return patchCallbackGo(_patcher, pos, len, _buf);
 }
 
+#ifndef RS_DEFAULT_STRONG_LEN
+// librsync >= 1.0.0, 0 is the full size (32 bytes)
+#define DEFAULT_STRONG_LEN 0
+#else
+// librsync < 1.0.0, using md4 (8 bytes)
+#define DEFAULT_STRONG_LEN RS_DEFAULT_STRONG_LEN
+#endif
+
+static inline rs_job_t* sig_begin(size_t new_block_len, size_t strong_sum_len, bool compat) {
+#ifndef RS_DEFAULT_STRONG_LEN
+	// librsync >= 1.0.0, supporting the newer hash function (blake2b)
+	if (compat) {
+		return rs_sig_begin(new_block_len, strong_sum_len, RS_MD4_SIG_MAGIC);
+	}
+	return rs_sig_begin(new_block_len, strong_sum_len, RS_BLAKE2_SIG_MAGIC);
+#else
+	// not supporting the newer hash function, fall back to the md4 hash
+	return rs_sig_begin(new_block_len, strong_sum_len);
+#endif
+}
+
 */
 import "C"
 
@@ -32,6 +54,11 @@ const (
 	outbufSize = 16 * 1024
 )
 
+const (
+	DefaultBlockLen  = C.RS_DEFAULT_BLOCK_LEN
+	DefaultStrongLen = C.DEFAULT_STRONG_LEN
+)
+
 var (
 	ErrInputEnded = errors.New("Input ended (possibly unexpected)")
 	ErrBadMagic   = errors.New("Bad magic number. Probably not an librsync file.")
@@ -74,24 +101,43 @@ func newJob(input io.Reader) (job *Job, err error) {
 	return
 }
 
-// NewDefaultSignatureGen is like NewSignatureGen, but uses default values for blocklen and stronglen.
+// Config sets parameters for NewSignatureGen. May be the zero value for default
+// values.
+type Config struct {
+	BlockLen  uint // length of a block, e.g. 2048
+	StrongLen uint // length of a strong hash, e.g. 32 or 0
+	CompatMD4 bool // enable for compatibility with librsync < 1.0.0
+}
+
+func (c *Config) setup() {
+	if c.BlockLen == 0 {
+		c.BlockLen = DefaultBlockLen
+	}
+	if c.StrongLen == 0 {
+		c.StrongLen = DefaultStrongLen
+	}
+}
+
+// NewDefaultSignatureGen is like NewSignatureGen, but uses the default
+// configuration.
 func NewDefaultSignatureGen(basis io.Reader) (job *Job, err error) {
-	job, err = NewSignatureGen(C.RS_DEFAULT_BLOCK_LEN, C.RS_DEFAULT_STRONG_LEN, basis)
+	job, err = NewSignatureGen(Config{}, basis)
 	return
 }
 
 // NewSignatureGen creates a signature generation job.
 //
-// blocklen is the length of a block.
-// stronglen is the length of the stong hash.
+// config is a Config object for more options.
 // basis is an io.Reader that provides data of the basis file.
-func NewSignatureGen(blocklen, stronglen uint, basis io.Reader) (job *Job, err error) {
+func NewSignatureGen(config Config, basis io.Reader) (job *Job, err error) {
 	job, err = newJob(basis)
 	if err != nil {
 		return
 	}
 
-	job.job = C.rs_sig_begin(C.size_t(blocklen), C.size_t(stronglen))
+	config.setup()
+
+	job.job = C.sig_begin(C.size_t(config.BlockLen), C.size_t(config.StrongLen), C.bool(config.CompatMD4))
 	if job.job == nil {
 		job.Close()
 		return nil, errors.New("rs_sig_begin failed")
diff --git a/librsync/librsync_test.go b/librsync/librsync_test.go
index 7c6a278..c291fac 100644
--- a/librsync/librsync_test.go
+++ b/librsync/librsync_test.go
@@ -22,7 +22,14 @@ func TestSignatureDeltaPatch(t *testing.T) {
 		t.Fatalf("Creating the signature failed: %s", err)
 	}
 
-	if !bytes.Equal(sigbuf.Bytes(), testdata.RandomDataSig()) {
+	matches := false
+	// Check both possible signatures.
+	for _, sigcheck := range testdata.RandomDataSig() {
+		if bytes.Equal(sigbuf.Bytes(), sigcheck) {
+			matches = true
+		}
+	}
+	if !matches {
 		if path, err := dump(sigbuf); err == nil {
 			t.Fatalf("Signatures do not match. Generated signature dumped to %s", path)
 		} else {
diff --git a/librsync/testdata/random_data.sig.go b/librsync/testdata/random_data.sig.go
index 8822edf..e5e57a3 100644
--- a/librsync/testdata/random_data.sig.go
+++ b/librsync/testdata/random_data.sig.go
@@ -1,12 +1,28 @@
 package testdata
 
-func RandomDataSig() []byte {
+func RandomDataSig() [][]byte {
 	// Was generated with `rdiff signature random_data random_data.sig`
-	return []byte{
-		0x72, 0x73, 0x01, 0x36, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00, 0x08,
-		0x60, 0xcb, 0xf7, 0x64, 0x2e, 0xbe, 0x39, 0x5e, 0x1a, 0xf2, 0x77, 0x07,
-		0xf5, 0x8f, 0xf3, 0xdc, 0x1d, 0xcc, 0xe0, 0x3b, 0x3b, 0xc9, 0x7e, 0x0d,
-		0x2e, 0xcf, 0xed, 0xc5, 0x09, 0x1f, 0xbb, 0x75, 0x27, 0xbb, 0x46, 0xa9,
-		0x86, 0x26, 0x04, 0xa1, 0x9d, 0x4d, 0xa3, 0x7a, 0xfa, 0xdd, 0x5d, 0xc5,
+	return [][]byte{
+		{
+			0x72, 0x73, 0x01, 0x36, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00, 0x08,
+			0x60, 0xcb, 0xf7, 0x64, 0x2e, 0xbe, 0x39, 0x5e, 0x1a, 0xf2, 0x77, 0x07,
+			0xf5, 0x8f, 0xf3, 0xdc, 0x1d, 0xcc, 0xe0, 0x3b, 0x3b, 0xc9, 0x7e, 0x0d,
+			0x2e, 0xcf, 0xed, 0xc5, 0x09, 0x1f, 0xbb, 0x75, 0x27, 0xbb, 0x46, 0xa9,
+			0x86, 0x26, 0x04, 0xa1, 0x9d, 0x4d, 0xa3, 0x7a, 0xfa, 0xdd, 0x5d, 0xc5,
+		}, {
+			0x72, 0x73, 0x01, 0x37, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00, 0x20,
+			0x60, 0xcb, 0xf7, 0x64, 0x3a, 0x2b, 0x95, 0x58, 0xad, 0xd8, 0xa9, 0x71,
+			0x70, 0x7d, 0x38, 0x64, 0xd5, 0xff, 0xa2, 0xc1, 0xae, 0xdf, 0x62, 0x76,
+			0x7a, 0x84, 0xf8, 0xa5, 0xc7, 0x68, 0xd9, 0xbd, 0x04, 0xea, 0x09, 0x2b,
+			0xf5, 0x8f, 0xf3, 0xdc, 0x13, 0x67, 0x5e, 0x50, 0xd9, 0xd3, 0x38, 0x47,
+			0x1c, 0xb9, 0x27, 0x60, 0x26, 0x8d, 0x23, 0x39, 0x47, 0x0e, 0x57, 0x2c,
+			0xfd, 0x2a, 0x27, 0xf1, 0xab, 0xee, 0x88, 0xe6, 0x74, 0x60, 0x78, 0xf8,
+			0x2e, 0xcf, 0xed, 0xc5, 0x3b, 0xef, 0xab, 0x41, 0x13, 0x93, 0x0e, 0x26,
+			0x38, 0x79, 0xc6, 0xed, 0x4d, 0xce, 0x65, 0xcd, 0x02, 0x5f, 0x2f, 0x19,
+			0x42, 0x4a, 0x2d, 0xac, 0x8f, 0xb1, 0x40, 0xa2, 0x3c, 0xfc, 0x90, 0x66,
+			0x86, 0x26, 0x04, 0xa1, 0x08, 0x25, 0xe4, 0x2c, 0xf7, 0x77, 0xa8, 0x7e,
+			0x8f, 0xbf, 0xe9, 0xdf, 0x7a, 0x2d, 0x89, 0xc3, 0xe8, 0x15, 0x65, 0x46,
+			0xa2, 0xe0, 0x33, 0x38, 0xc9, 0x73, 0xf0, 0xc3, 0x20, 0x79, 0x5a, 0x11,
+		},
 	}
 }
diff --git a/librsync/testdata/random_data.sig2 b/librsync/testdata/random_data.sig2
new file mode 100644
index 0000000..684eacc
--- /dev/null
+++ b/librsync/testdata/random_data.sig2