feat: create the eth abi decoding

src/lua/crypto_ethereum.lua

@@ -559,31 +559,39 @@ function ETH.contract_return_factory(params)
 
       local res = {}
       for i, v in ipairs(params) do
-	 -- I don't check the range of values (for bool the input should be 0 or 1),
-	 -- while for int<M> should be 0 ... 2^(<M>)-1
-	 if v == 'address' or string.match(v, '^uint%d+$') then
-	    table.insert(res, BIG.new(val:sub(32 * (i-1)+1, 32 * i)))
-	 elseif v == 'bool' then
-	    table.insert(res, BIG.new(val:sub(32 * (i-1)+1, 32 * i)) ~= BIG.new(0))
-	 elseif v == 'string' or v == 'bytes' then
-	    -- TODO: don't know the maximum size of argument
-	    -- there could be an overflow
-	    local offset = tonumber(val:sub(32 * (i-1)+1, 32 * i):hex(), 16)
-	    local slen = tonumber(val:sub(1+offset, 32+offset):hex(), 16)
-	    local s = val:sub(1+offset+32, offset+32+slen):string()
+         -- I don't check the range of values (for bool the input should be 0 or 1),
+         -- while for int<M> should be 0 ... 2^(<M>)-1
+         if v == 'address' or string.match(v, '^uint%d+$') then
+            local val = BIG.new(val:sub(32 * (i-1)+1, 32 * i))
+            if v == 'address' then
+               val = val:fixed(32)
+            end
+            table.insert(res, val)
+         elseif v == 'bool' then
+            table.insert(res, BIG.new(val:sub(32 * (i-1)+1, 32 * i)) ~= BIG.new(0))
+         elseif v == 'string' or v == 'bytes' then
+            -- TODO: don't know the maximum size of argument
+            -- there could be an overflow
+            local offset = tonumber(val:sub(32 * (i-1)+1, 32 * i):hex(), 16)
+            local slen = tonumber(val:sub(1+offset, 32+offset):hex(), 16)
+            local s = val:sub(1+offset+32, offset+32+slen):string()
             if v == 'string' then
-              s = s:string()
+               s = s:string()
             end
-	    table.insert(res, s)
-	 else
-	    assert(false, "Unknown data type")
-	 end
+            table.insert(res, s)
+         elseif v == "bytes32" then -- TODO: for any bytesXX
+            local val = val:sub(32 * (i-1)+1, 32 * i)
+            table.insert(res, val)
+         else
+            assert(false, "Unknown data type")
+         end
       end
 
       return res
    end
 end
 
+ETH.abi_decode = ETH.contract_return_factory
 
 -- methods with the modifier "view" have to be executed (locally) with
 -- eth_call, they don't change the blockchain

src/lua/zencode_ethereum.lua

@@ -391,6 +391,25 @@ When("create the ethereum abi encoding of '' using ''", function(t, args)
     new_codec('ethereum abi encoding', {encoding = 'hex'})
 end)
 
+When("create the ethereum abi decoding of '' using ''", function(t, args)
+    -- We imply that t is an octet/octet array and args is a single string/a string array
+    local data = have(t)
+    local o_type_spec = have(args)
+    local type_spec
+    -- TODO: support for nested array using deepmap.
+    if(type(o_type_spec) == "table") then
+        type_spec = {}
+        for i,v in pairs(o_type_spec) do
+            type_spec[i] = O.to_string(v)
+        end
+    else
+        type_spec = O.to_string(o_type_spec)
+    end
+    empty'ethereum abi decoding'
+    ACK.ethereum_abi_decoding = ETH.abi_decode(type_spec)(data)
+    new_codec('ethereum abi decoding', {zentype="a"})
+end)
+
 When("create the ethereum signature of ''", function(object)
     local sk = havekey'ethereum'
     local data = have(object)

test/zencode/ethereum.bats

@@ -853,3 +853,36 @@ EOF
     save_output eth_sign_arr_eth_add_dict_out.json
     assert_output '{"addresses":{"first":"0x2B8070975AF995Ef7eb949AE28ee7706B9039504","second":"0x3028806AC293B5aC9b863B685c73813626311DaD","third":"0xe1C2F1ACb2758c4D88EDb84e0306A0a96682E62a"},"signatures":["0xed8f36c71989f8660e8f5d4adbfd8f1c0288cca90d3a5330b7bf735d71ab52fe7ba0a7827dc4ba707431f1c10babd389f658f8e208b89390a9be3c097579a2ff1b","0x40d305373c648bb6b2bbadebe02ada256a9d0b3d3c37367c0a2795e367b22f7372e40dfc3497927764d1585783d058e4367bb4d24d2107777d7aa4ddcb6593c71b","0x9e07477c31db612e8c99a950385162373ff41a5b8941470b1aeba43b76c5357005fce6615567dc1944cc02fbed86202b09d92d79fbade425af0d74c328d8f6ae1c"]}'
 }
+
+@test "ABI decoding" {
+    cat <<EOF | save_asset 'eth_abi_decoding.data'
+{
+    "typeSpec": [
+        "uint256",
+        "bytes32",
+        "uint256"
+    ],
+    "encoded_data": "00000000000000000000000000000000000000000000000000000000000000c848656c6c6f20576f726c6400000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000d3"
+}
+EOF
+    cat <<EOF | zexe eth_abi_decoding.zen eth_abi_decoding.data
+Scenario ethereum
+
+Given I have a 'hex' named 'encoded data'
+Given I have a 'string array' named 'typeSpec'
+
+When I create the ethereum abi decoding of 'encoded data' using 'typeSpec'
+When I create the copy of element '1' in array 'ethereum abi decoding'
+When I rename 'copy' to 'request_id'
+When I create the copy of element '2' in array 'ethereum abi decoding'
+When I rename 'copy' to 'data'
+When I create the copy of element '3' in array 'ethereum abi decoding'
+When I rename 'copy' to 'dao_vote_id'
+
+Then print the 'request_id' as 'integer'
+Then print the 'data' as 'hex'
+Then print the 'dao_vote_id' as 'integer'
+EOF
+    save_output 'eth_abi_decoding.json'
+    assert_output '{"dao_vote_id":"211","data":"48656c6c6f20576f726c64000000000000000000000000000000000000000000","request_id":"200"}'
+}