chore: (x/authz) add helpers AppendBytes, ParseByteSlice (#11713)

types/utils.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/cosmos/cosmos-sdk/types/kv"
 	dbm "github.com/tendermint/tm-db"
 )
 
@@ -106,3 +107,30 @@ func CopyBytes(bz []byte) (ret []byte) {
 	copy(ret, bz)
 	return ret
 }
+
+// AppendLengthPrefixedBytes combines the slices of bytes to one slice of bytes.
+func AppendLengthPrefixedBytes(args ...[]byte) []byte {
+	length := 0
+	for _, v := range args {
+		length += len(v)
+	}
+	res := make([]byte, length)
+
+	length = 0
+	for _, v := range args {
+		copy(res[length:length+len(v)], v)
+		length += len(v)
+	}
+
+	return res
+}
+
+// ParseLengthPrefixedBytes panics when store key length is not equal to the given length.
+func ParseLengthPrefixedBytes(key []byte, startIndex int, sliceLength int) ([]byte, int) {
+	neededLength := startIndex + sliceLength
+	endIndex := neededLength - 1
+	kv.AssertKeyAtLeastLength(key, neededLength)
+	byteSlice := key[startIndex:neededLength]
+
+	return byteSlice, endIndex
+}

types/utils_test.go

@@ -8,6 +8,7 @@ import (
 	"github.com/stretchr/testify/suite"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/types/address"
 )
 
 type utilsTestSuite struct {
@@ -109,3 +110,23 @@ func (s *utilsTestSuite) TestParseTimeBytes() {
 	_, err = sdk.ParseTimeBytes([]byte{})
 	s.Require().Error(err)
 }
+
+func (s *utilsTestSuite) TestAppendParseBytes() {
+	test1 := "test1"
+	test2 := "testString2"
+	testByte1 := []byte(test1)
+	testByte2 := []byte(test2)
+
+	combinedBytes := sdk.AppendLengthPrefixedBytes(address.MustLengthPrefix(testByte1), address.MustLengthPrefix(testByte2))
+	testCombineBytes := append([]byte{}, address.MustLengthPrefix(testByte1)...)
+	testCombineBytes = append(testCombineBytes, address.MustLengthPrefix(testByte2)...)
+	s.Require().Equal(combinedBytes, testCombineBytes)
+
+	test1Len, test1LenEndIndex := sdk.ParseLengthPrefixedBytes(combinedBytes, 0, 1)
+	parseTest1, parseTest1EndIndex := sdk.ParseLengthPrefixedBytes(combinedBytes, test1LenEndIndex+1, int(test1Len[0]))
+	s.Require().Equal(testByte1, parseTest1)
+
+	test2Len, test2LenEndIndex := sdk.ParseLengthPrefixedBytes(combinedBytes, parseTest1EndIndex+1, 1)
+	parseTest2, _ := sdk.ParseLengthPrefixedBytes(combinedBytes, test2LenEndIndex+1, int(test2Len[0]))
+	s.Require().Equal(testByte2, parseTest2)
+}