web3.js/lib/utils.js

82 lines
2.1 KiB
JavaScript

/*
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 utils.js
* @authors:
* Marek Kotewicz <marek@ethdev.com>
* @date 2015
*/
/// Finds first index of array element matching pattern
/// @param array
/// @param callback pattern
/// @returns index of element
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;
};
/// @returns ascii string representation of hex value prefixed with 0x
var toAscii = function(hex) {
// Find termination
var str = "";
var i = 0, l = hex.length;
if (hex.substring(0, 2) === '0x') {
i = 2;
}
for (; i < l; i+=2) {
var code = parseInt(hex.substr(i, 2), 16);
if (code === 0) {
break;
}
str += String.fromCharCode(code);
}
return str;
};
var toHex = function(str) {
var hex = "";
for(var i = 0; i < str.length; i++) {
var n = str.charCodeAt(i).toString(16);
hex += n.length < 2 ? '0' + n : n;
}
return hex;
};
/// @returns hex representation (prefixed by 0x) of ascii string
var fromAscii = function(str, pad) {
pad = pad === undefined ? 0 : pad;
var hex = toHex(str);
while (hex.length < pad*2)
hex += "00";
return "0x" + hex;
};
module.exports = {
findIndex: findIndex,
toAscii: toAscii,
fromAscii: fromAscii
};