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"use strict"; | ||
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// Run me with Node to see my output! | ||
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let util = require("util"); | ||
let P = require(".."); | ||
let B = P.Binary; | ||
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/////////////////////////////////////////////////////////////////////// | ||
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// Try using another string encoding here! | ||
let STRING_ENCODING = "utf8"; | ||
// let STRING_ENCODING = "ucs2"; | ||
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// Try rearranging these items | ||
let DIRECTIONS_ENUM = ["up", "down", "left", "right"]; | ||
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let Lang = P.createLanguage({ | ||
File: p => | ||
P.seqObj( | ||
p.MagicNumber, | ||
["directions", p.Directions5], | ||
["array", p.Int32Array], | ||
["double", B.doubleLE], | ||
["string", p.String] | ||
), | ||
Directions5: () => | ||
B.bitSeq([ | ||
6, // 6 ignored bits | ||
2, // 2-bit direction #1 | ||
2, // 2-bit direction #2 | ||
2, // 2-bit direction #3 | ||
2, // 2-bit direction #4 | ||
2 // 2-bit direction #5 | ||
]).map(xs => { | ||
return xs.slice(1).map(x => DIRECTIONS_ENUM[x]); | ||
}), | ||
MagicNumber: () => P.seq(B.byte(0x13), B.byte(0x37)), | ||
Int32: () => B.int32BE, | ||
UInt32: () => B.uint32BE, | ||
String: p => p.UInt32.chain(n => B.encodedString(STRING_ENCODING, n)), | ||
Int32Array: p => p.UInt32.chain(n => p.Int32.times(n)) | ||
}); | ||
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/////////////////////////////////////////////////////////////////////// | ||
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// File format: | ||
// - Magic number: hexadecimal "1337" byte sequence | ||
// - 6 ignored bits | ||
// - 10 bits where each pair of bits represents up/down/left/right | ||
// - 0 = 0b00 = up | ||
// - 1 = 0b01 = down | ||
// - 2 = 0b10 = left | ||
// - 3 = 0b11 = right | ||
// - Array length: 32-bit unsigned big-endian integer | ||
// - 32-bit signed integers up to the array length | ||
// - A double precision floating point little-endian number | ||
// - A 32-bit unsigned big-endian integer for the string length | ||
// - "string length" number of UTF-8 bytes | ||
// - End of file | ||
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let magic = [0x13, 0x37]; | ||
let length = [0x00, 0x00, 0x00, 0x02]; | ||
let directions = [0b00000011, 0b00101101]; | ||
let n512 = [0x00, 0x00, 0x02, 0x00]; | ||
let n513 = [0x00, 0x00, 0x02, 0x01]; | ||
let LENGTH_DOUBLE = 8; | ||
let LENGTH_INT32 = 4; | ||
let d314 = Buffer.alloc(LENGTH_DOUBLE); | ||
d314.writeDoubleLE(Math.PI); | ||
let testString = "«Piña Colada® is a beverage!»"; | ||
let testStringByteLength = Buffer.from(testString, STRING_ENCODING).length; | ||
let str = Buffer.alloc(LENGTH_INT32 + testStringByteLength); | ||
let index = 0; | ||
index += str.writeUInt32BE(testStringByteLength, index); | ||
index += str.write(testString, index, testStringByteLength, STRING_ENCODING); | ||
index; | ||
let bytes = [ | ||
...magic, | ||
...directions, | ||
...length, | ||
...n512, | ||
...n513, | ||
...d314, | ||
...str | ||
]; | ||
let input = Buffer.from(bytes); | ||
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function prettyPrint(x) { | ||
let opts = { depth: null, colors: "auto" }; | ||
let s = util.inspect(x, opts); | ||
console.log(s); | ||
} | ||
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let ast = Lang.File.tryParse(input); | ||
prettyPrint(ast); |