accounts/abi: added a parsing file and added some notes and building blocks. Might be slightly inaccurate, needs testing.

Signed-off-by: RJ Catalano <rj@monax.io>

accounts/abi/parsing.go

@@ -0,0 +1,48 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package abi
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+// separates byte slice into a slice of 32 byte slices.
+func chunkBytes(output []byte) (chunked [][32]byte) {
+	for i, j := 0, 0; i < len(output); i, j = i+32, j+1 {
+		chunked[j] = output[i : i+32]
+	}
+	return
+}
+
+// check to see that the bytes are correctly formatted to 32 byte slices
+func bytesAreProper(output []byte) error {
+	if len(output)%32 != 0 {
+		return fmt.Errorf("abi: improper length of byte slice detected in output.")
+	}
+	return nil
+}
+
+// interprets a 32 byte slice as an offset and then determines which indice to look to decode the type.
+func offsetPointsTo(offset [32]byte) uint {
+	return uint(binary.BigEndian.Uint64(offset[24:32])) / 32
+}
+
+// gives the starting and ending indices in the chunked byte slice for the values of an array
+func parseSliceSize(size [32]byte, currentLength uint) (start uint, end uint) {
+	return currentLength + 1, currentLength + uint(binary.BigEndian.Uint64(size[24:32])/32)
+}

accounts/abi/type.go

@@ -33,7 +33,7 @@ const (
 	FixedBytesTy
 	BytesTy
 	HashTy
-	FixedpointTy
+	FixedPointTy
 	FunctionTy
 )
 

accounts/abi/unpacking.go

@@ -139,6 +139,7 @@ func readInteger(kind reflect.Kind, b []byte) interface{} {
 	}
 }
 
+// todo: this is inefficient for a bool, just look at the last cell, save yourself 32 iterations
 func allZero(b []byte) bool {
 	for _, byte := range b {
 		if byte != 0 {