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/*
This file is part of ethereum.js.
ethereum.js 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.
ethereum.js 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 ethereum.js. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file abi.js
* @authors:
* Marek Kotewicz <marek@ethdev.com>
* Gav Wood <g@ethdev.com>
* @date 2014
*/
// TODO: make these be actually accurate instead of falling back onto JS's doubles.
var hexToDec = function (hex) {
return parseInt(hex, 16).toString();
};
var decToHex = function (dec) {
return parseInt(dec).toString(16);
};
var findIndex = function (array, callback) {
var end = false;
var i = 0;
for (; i < array.length && !end; i++) {
end = callback(array[i]);
}
return end ? i - 1 : -1;
};
var findMethodIndex = function (json, methodName) {
return findIndex(json, function (method) {
return method.name === methodName;
});
};
var padLeft = function (string, chars) {
return Array(chars - string.length + 1).join("0") + string;
};
var setupInputTypes = function () {
var prefixedType = function (prefix) {
return function (type, value) {
var expected = prefix;
if (type.indexOf(expected) !== 0) {
return false;
}
var padding = parseInt(type.slice(expected.length)) / 8;
if (typeof value === "number")
value = value.toString(16);
else if (value.indexOf('0x') === 0)
value = value.substr(2);
else
value = (+value).toString(16);
return padLeft(value, padding * 2);
};
};
var namedType = function (name, padding, formatter) {
return function (type, value) {
if (type !== name) {
return false;
}
return padLeft(formatter ? formatter(value) : value, padding * 2);
};
};
var formatBool = function (value) {
return value ? '0x1' : '0x0';
};
return [
prefixedType('uint'),
prefixedType('int'),
prefixedType('hash'),
namedType('address', 20),
namedType('bool', 1, formatBool),
];
};
var inputTypes = setupInputTypes();
var toAbiInput = function (json, methodName, params) {
var bytes = "";
var index = findMethodIndex(json, methodName);
if (index === -1) {
return;
}
bytes = "0x" + padLeft(index.toString(16), 2);
var method = json[index];
for (var i = 0; i < method.inputs.length; i++) {
var found = false;
for (var j = 0; j < inputTypes.length && !found; j++) {
found = inputTypes[j](method.inputs[i].type, params[i]);
}
if (!found) {
console.error('unsupported json type: ' + method.inputs[i].type);
}
bytes += found;
}
return bytes;
};
var setupOutputTypes = function () {
var prefixedType = function (prefix) {
return function (type) {
var expected = prefix;
if (type.indexOf(expected) !== 0) {
return -1;
}
var padding = parseInt(type.slice(expected.length)) / 8;
return padding * 2;
};
};
var namedType = function (name, padding) {
return function (type) {
return name === type ? padding * 2 : -1;
};
};
var formatInt = function (value) {
return value.length <= 8 ? +parseInt(value, 16) : hexToDec(value);
};
var formatHash = function (value) {
return "0x" + value;
};
var formatBool = function (value) {
return value === '1' ? true : false;
};
return [
{ padding: prefixedType('uint'), format: formatInt },
{ padding: prefixedType('int'), format: formatInt },
{ padding: prefixedType('hash'), format: formatHash },
{ padding: namedType('address', 20) },
{ padding: namedType('bool', 1), format: formatBool }
];
};
var outputTypes = setupOutputTypes();
var fromAbiOutput = function (json, methodName, output) {
var index = findMethodIndex(json, methodName);
if (index === -1) {
return;
}
output = output.slice(2);
var result = [];
var method = json[index];
for (var i = 0; i < method.outputs.length; i++) {
var padding = -1;
for (var j = 0; j < outputTypes.length && padding === -1; j++) {
padding = outputTypes[j].padding(method.outputs[i].type);
}
if (padding === -1) {
// not found output parsing
continue;
}
var res = output.slice(0, padding);
var formatter = outputTypes[j - 1].format;
result.push(formatter ? formatter(res) : ("0x" + res));
output = output.slice(padding);
}
return result;
};
var inputParser = function (json) {
var parser = {};
json.forEach(function (method) {
parser[method.name] = function () {
var params = Array.prototype.slice.call(arguments);
return toAbiInput(json, method.name, params);
};
});
return parser;
};
var outputParser = function (json) {
var parser = {};
json.forEach(function (method) {
parser[method.name] = function (output) {
return fromAbiOutput(json, method.name, output);
};
});
return parser;
};
module.exports = {
inputParser: inputParser,
outputParser: outputParser
};
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