| 1 | 1 | 'use strict'; |
| 2 | | |
| 3 | | // ---------------------------------------------------------------------- |
| 4 | | // ----- main exported object |
| 5 | | // includes: |
| 6 | | // 1. unit conversions |
| 7 | | // 2. arithmetic functions |
| 8 | | // 3. logical operators |
| 9 | | // 4. helper methods |
| 10 | | // ---------------------------------------------------------------------- |
| 11 | | |
| 12 | 1 | var binary = module.exports = {}; |
| 13 | | |
| 14 | | |
| 15 | | // ----- unit conversion |
| 16 | | // --------------------------------------- |
| 17 | 1 | binary.toInt = function(str) { |
| 18 | 10 | return parseInt(str, 2); |
| 19 | | }; |
| 20 | | |
| 21 | 1 | binary.toHex = function(str) { |
| 22 | 2 | return parseInt(str, 2).toString(16); |
| 23 | | }; |
| 24 | | |
| 25 | | // binary.toBase64 = function(str) { |
| 26 | | // str = parseInt(str, 2).toString(); |
| 27 | | // var buf = new Buffer(str); |
| 28 | | // return buf.toString('base64'); |
| 29 | | // }; |
| 30 | | |
| 31 | | // @param n {Number | String | Buffer} input |
| 32 | | // @return {String} 8bit binary conversion |
| 33 | | // todo: get more test cases & verify |
| 34 | 1 | binary.toBinary = function(n) { |
| 35 | | |
| 36 | 6 | var type = Object.prototype.toString.call(n); |
| 37 | | |
| 38 | 6 | if (type === '[object Number]') { |
| 39 | 2 | return n.toString(2); |
| 40 | | } |
| 41 | | |
| 42 | 4 | var output = ''; |
| 43 | | |
| 44 | 4 | for (var i = 0; i < n.length; i++) { |
| 45 | | |
| 46 | 22 | var cur = typeof n[i] === 'number' ? |
| 47 | | binary.pad(n[i].toString(2), 8) // buffers |
| 48 | | : binary.pad(n.charCodeAt(i).toString(2), 8); // strings |
| 49 | | |
| 50 | 22 | output += cur; |
| 51 | | |
| 52 | | } |
| 53 | | |
| 54 | 4 | return output; |
| 55 | | |
| 56 | | }; |
| 57 | | |
| 58 | | |
| 59 | | // @param str {String} binary string |
| 60 | | // @return {String} Unicode string |
| 61 | 1 | binary.toUnicode = function(str) { |
| 62 | | |
| 63 | 2 | var arr = binary.split(str); |
| 64 | 2 | var output = ''; |
| 65 | | |
| 66 | 2 | for (var i=0, len=arr.length; i<len; i++) { |
| 67 | 6 | var integer = binary.toInt(arr[i]); |
| 68 | 6 | output += String.fromCharCode(integer); |
| 69 | | } |
| 70 | | |
| 71 | 2 | return output; |
| 72 | | |
| 73 | | }; |
| 74 | | |
| 75 | | |
| 76 | | // ----- arithmetic |
| 77 | | // --------------------------------------- |
| 78 | | |
| 79 | | // @param a {String} binary number |
| 80 | | // @param b {String} binary number |
| 81 | | // todo: @param n {Number} optional bitLength restriction |
| 82 | 1 | binary.add = function(a, b) { |
| 83 | 6 | a = parseInt(a, 2); |
| 84 | 6 | b = parseInt(b, 2); |
| 85 | 6 | return (a + b).toString(2); |
| 86 | | }; |
| 87 | | |
| 88 | 1 | binary.addBits = function(a, b) { |
| 89 | 4 | a = a === '1' ? 1 : 0; |
| 90 | 4 | b = b === '1' ? 1 : 0; |
| 91 | | |
| 92 | 4 | var sum = a ^ b; |
| 93 | 4 | var carry = a & b; |
| 94 | | |
| 95 | 4 | return { |
| 96 | | sum: sum.toString(), |
| 97 | | carry: carry.toString() |
| 98 | | }; |
| 99 | | }; |
| 100 | | |
| 101 | | // @param a {String} binary number |
| 102 | | // @param b {String} binary number |
| 103 | | // todo: @param n {Number} optional bitLength restriction |
| 104 | 1 | binary.multiply = function(a, b) { |
| 105 | 6 | a = parseInt(a, 2); |
| 106 | 6 | b = parseInt(b, 2); |
| 107 | 6 | return (a * b).toString(2); |
| 108 | | }; |
| 109 | | |
| 110 | | // @param a {String} binary number |
| 111 | | // @param b {String} binary number |
| 112 | | // todo: @param n {Number} optional bitLength restriction |
| 113 | 1 | binary.divide = function(a, b) { |
| 114 | 6 | a = parseInt(a, 2); |
| 115 | 6 | b = parseInt(b, 2); |
| 116 | 6 | return (a / b).toString(2); |
| 117 | | }; |
| 118 | | |
| 119 | | |
| 120 | | // ----- logic |
| 121 | | // --------------------------------------- |
| 122 | 1 | binary.not = function(str) { |
| 123 | 13 | var inverse = ''; |
| 124 | 13 | for (var i = 0; i < str.length; i++) { |
| 125 | 79 | inverse += str[i] === '1' ? '0' : '1'; |
| 126 | | } |
| 127 | 13 | return inverse; |
| 128 | | }; |
| 129 | | |
| 130 | 1 | binary.and = function(a, b) { |
| 131 | | |
| 132 | 7 | var eq = binary.equalize(a, b); |
| 133 | 7 | a = eq[0]; |
| 134 | 7 | b = eq[1]; |
| 135 | | |
| 136 | 7 | var result = ''; |
| 137 | | |
| 138 | 7 | for (var i = 0; i < a.length; i++) { |
| 139 | 28 | if (a[i] === b[i]) { |
| 140 | 6 | result += a[i]; |
| 141 | | } |
| 142 | | else { |
| 143 | 22 | result += '0'; |
| 144 | | } |
| 145 | | } |
| 146 | | |
| 147 | 7 | return result; |
| 148 | | |
| 149 | | }; |
| 150 | | |
| 151 | 1 | binary.or = function(a, b) { |
| 152 | | |
| 153 | 8 | var eq = binary.equalize(a, b); |
| 154 | 8 | a = eq[0]; |
| 155 | 8 | b = eq[1]; |
| 156 | | |
| 157 | 8 | var result = ''; |
| 158 | | |
| 159 | 8 | for (var i = 0; i < a.length; i++) { |
| 160 | 32 | if (a[i] === '1' || b[i] === '1') { |
| 161 | 30 | result += '1'; |
| 162 | | } |
| 163 | | else { |
| 164 | 2 | result += '0'; |
| 165 | | } |
| 166 | | } |
| 167 | | |
| 168 | 8 | return result; |
| 169 | | |
| 170 | | }; |
| 171 | | |
| 172 | 1 | binary.nand = function(a, b) { |
| 173 | 3 | var and = binary.and(a, b); |
| 174 | 3 | return binary.not(and); |
| 175 | | }; |
| 176 | | |
| 177 | 1 | binary.nor = function(a, b) { |
| 178 | 4 | var or = binary.or(a, b); |
| 179 | 4 | return binary.not(or); |
| 180 | | }; |
| 181 | | |
| 182 | 1 | binary.xor = function(a, b) { |
| 183 | | |
| 184 | 4 | var eq = binary.equalize(a, b); |
| 185 | 4 | a = eq[0]; |
| 186 | 4 | b = eq[1]; |
| 187 | | |
| 188 | 4 | var result = ''; |
| 189 | | |
| 190 | 4 | for (var i = 0; i < a.length; i++) { |
| 191 | 16 | if (a[i] !== b[i]) { |
| 192 | 13 | result += '1'; |
| 193 | | } |
| 194 | | else { |
| 195 | 3 | result += '0'; |
| 196 | | } |
| 197 | | } |
| 198 | | |
| 199 | 4 | return result; |
| 200 | | |
| 201 | | }; |
| 202 | | |
| 203 | 1 | binary.complement = function(str) { |
| 204 | 4 | var inverse = binary.not(str); |
| 205 | 4 | var complement = binary.add(inverse, 1); |
| 206 | 4 | return binary.pad(complement, str.length); |
| 207 | | }; |
| 208 | | |
| 209 | | |
| 210 | | // ----- etc |
| 211 | | // --------------------------------------- |
| 212 | | |
| 213 | | // @param str {String} binary string |
| 214 | | // @param n {Number} length of output |
| 215 | | // @return {String} left-padded binary string |
| 216 | 1 | binary.pad = function(str, n) { |
| 217 | 40 | while (str.length < n) { |
| 218 | 62 | str = '0' + str; |
| 219 | | } |
| 220 | 40 | return str; |
| 221 | | }; |
| 222 | | |
| 223 | | // @param str {String} binary string |
| 224 | | // @param n {Number} length of output |
| 225 | | // @param fn {Function} callback |
| 226 | | // @return {Function} callback(err, result) |
| 227 | 1 | binary.padSafe = function(str, n, fn) { |
| 228 | | |
| 229 | 2 | while (str.length < n) { |
| 230 | 4 | str = '0' + str; |
| 231 | | } |
| 232 | | |
| 233 | 2 | if (str.length > n) { |
| 234 | 1 | var err = new Error('input length exceeds expected length of output'); |
| 235 | 1 | return fn(err, str); |
| 236 | | } |
| 237 | | |
| 238 | 1 | return fn(null, str); |
| 239 | | |
| 240 | | }; |
| 241 | | |
| 242 | | // @param a {String} binary string |
| 243 | | // @param b {String} binary string |
| 244 | | // @return {Array} [(padded) a, (padded) b] |
| 245 | 1 | binary.equalize = function(a, b) { |
| 246 | | |
| 247 | 21 | var aLen = a.length; |
| 248 | 21 | var bLen = b.length; |
| 249 | | |
| 250 | 21 | if (aLen > bLen) { |
| 251 | 1 | b = binary.pad(b, aLen); |
| 252 | | } |
| 253 | | |
| 254 | 21 | if (bLen > aLen) { |
| 255 | 10 | a = binary.pad(a, bLen); |
| 256 | | } |
| 257 | | |
| 258 | 21 | return [a, b]; |
| 259 | | |
| 260 | | }; |
| 261 | | |
| 262 | | // @param str {String} binary string |
| 263 | | // @param length {Number} optional number of characters per chunk; default is 8 |
| 264 | | // @return {Array} |
| 265 | 1 | binary.split = function(str, length) { |
| 266 | 6 | if (!length) { |
| 267 | 3 | length = 8; |
| 268 | | } |
| 269 | 6 | var regex = new RegExp('.{1,' + length + '}', 'g'); // /.{1,8}/g |
| 270 | 6 | return str.match(regex); |
| 271 | | }; |
| 272 | | |
| 273 | | // @param arr {Array} array of equal length binary strings |
| 274 | | // @return {String} least significant bits |
| 275 | 1 | binary.lsb = function(arr) { |
| 276 | | |
| 277 | 1 | var output = ''; |
| 278 | | |
| 279 | 1 | for (var i=0, len=arr.length; i<len; i++) { |
| 280 | 14 | var byteLength = arr[i].length; |
| 281 | 14 | var bit = arr[i][byteLength - 1]; |
| 282 | 14 | var out = bit === '0' ? '0' : '1'; |
| 283 | 14 | output += out; |
| 284 | | } |
| 285 | | |
| 286 | 1 | return output; |
| 287 | | |
| 288 | | }; |