Feature/c2c temp

data/transactions/logic/TEAL_opcodes.md

@@ -778,6 +778,17 @@ When A is a uint64, index 0 is the least significant bit. Setting bit 3 to 1 on
 
 Decodes A using the base64 encoding E. Specify the encoding with an immediate arg either as URL and Filename Safe (`URLEncoding`) or Standard (`StdEncoding`). See <a href="https://rfc-editor.org/rfc/rfc4648.html#section-4">RFC 4648</a> (sections 4 and 5). It is assumed that the encoding ends with the exact number of `=` padding characters as required by the RFC. When padding occurs, any unused pad bits in the encoding must be set to zero or the decoding will fail. The special cases of `\n` and `\r` are allowed but completely ignored. An error will result when attempting to decode a string with a character that is not in the encoding alphabet or not one of `=`, `\r`, or `\n`.
 
+## base64_decode e
+
+- Opcode: 0x5c {uint8 encoding index}
+- Pops: *... stack*, []byte
+- Pushes: []byte
+- decode X which was base64-encoded using _encoding_ E. Fail if X is not base64 encoded with encoding E
+- **Cost**: 25
+- LogicSigVersion >= 6
+
+Decodes X using the base64 encoding E. Specify the encoding with an immediate arg either as URL and Filename Safe (`URLEncoding`) or Standard (`StdEncoding`). See <a href="https://rfc-editor.org/rfc/rfc4648.html#section-4">RFC 4648</a> (sections 4 and 5). It is assumed that the encoding ends with the exact number of `=` padding characters as required by the RFC. When padding occurs, any unused pad bits in the encoding must be set to zero or the decoding will fail. The special cases of `\n` and `\r` are allowed but completely ignored. An error will result when attempting to decode a string with a character that is not in the encoding alphabet or not one of `=`, `\r`, or `\n`.
+
 ## balance
 
 - Opcode: 0x60

data/transactions/logic/fields.go

@@ -565,6 +565,44 @@ func (s base64EncodingSpecMap) getExtraFor(name string) (extra string) {
 	return
 }
 
+// Base64Encoding is an enum for the `base64decode` opcode
+type Base64Encoding int
+
+const (
+	// URLEncoding represents the base64url encoding defined in https://www.rfc-editor.org/rfc/rfc4648.html
+	URLEncoding Base64Encoding = iota
+	// StdEncoding represents the standard encoding of the RFC
+	StdEncoding
+	invalidBase64Alphabet
+)
+
+// After running `go generate` these strings will be available:
+var base64EncodingNames [2]string = [...]string{URLEncoding.String(), StdEncoding.String()}
+
+type base64EncodingSpec struct {
+	field   Base64Encoding
+	ftype   StackType
+	version uint64
+}
+
+var base64EncodingSpecs = []base64EncodingSpec{
+	{URLEncoding, StackBytes, 6},
+	{StdEncoding, StackBytes, 6},
+}
+
+var base64EncodingSpecByField map[Base64Encoding]base64EncodingSpec
+var base64EncodingSpecByName base64EncodingSpecMap
+
+type base64EncodingSpecMap map[string]base64EncodingSpec
+
+func (s base64EncodingSpecMap) getExtraFor(name string) (extra string) {
+	// Uses 6 here because base64_decode fields were introduced in 6
+	if s[name].version > 6 {
+		extra = fmt.Sprintf("LogicSigVersion >= %d.", s[name].version)
+	}
+	return
+}
+
 // AssetHoldingField is an enum for `asset_holding_get` opcode
 type AssetHoldingField int
 
@@ -854,6 +892,16 @@ func init() {
 		base64EncodingSpecByName[encoding] = base64EncodingSpecByField[Base64Encoding(i)]
 	}
 
+	base64EncodingSpecByField = make(map[Base64Encoding]base64EncodingSpec, len(base64EncodingNames))
+	for _, s := range base64EncodingSpecs {
+		base64EncodingSpecByField[s.field] = s
+	}
+
+	base64EncodingSpecByName = make(base64EncodingSpecMap, len(base64EncodingNames))
+	for i, encoding := range base64EncodingNames {
+		base64EncodingSpecByName[encoding] = base64EncodingSpecByField[Base64Encoding(i)]
+	}
+
 	AssetHoldingFieldNames = make([]string, int(invalidAssetHoldingField))
 	for i := AssetBalance; i < invalidAssetHoldingField; i++ {
 		AssetHoldingFieldNames[int(i)] = i.String()