Add additional checks in chunking functionality (#671)

sdk/checksum/checksum.go

@@ -26,13 +26,26 @@ func HexChecksum(b []byte) string {
 // Chunk - split bytes to chunk limits
 func Chunk(buf []byte, lim int) [][]byte {
 	var chunk []byte
-	chunks := make([][]byte, 0, len(buf)/lim+1)
+	bufSize := len(buf)
+
+	if bufSize == 0 {
+		return [][]byte{}
+	}
+
+	if bufSize <= lim {
+		return [][]byte{buf}
+	}
+
+	chunks := make([][]byte, 0)
+
 	for len(buf) >= lim {
 		chunk, buf = buf[:lim], buf[lim:]
 		chunks = append(chunks, chunk)
 	}
+
 	if len(buf) > 0 {
 		chunks = append(chunks, buf[:])
 	}
+
 	return chunks
 }

sdk/checksum/checksum_test.go

@@ -87,6 +87,7 @@ func TestHexChunk(t *testing.T) {
 			expected: [][]byte{},
 		},
 	}
+
 	for _, test := range tests {
 		result := Chunk(test.input, test.limit)
 		assert.Equal(t, test.expected, result)