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Move var_int to core structures module

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This commit is contained in:
Kagami Hiiragi 2015-01-01 22:26:06 +03:00
parent 49595f231e
commit 18e38dee2b
5 changed files with 154 additions and 144 deletions
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10
lib/address.js
View File

@ -11,7 +11,7 @@ require("object.assign").shim();
var assert = require("assert");
var bufferEqual = require("buffer-equal");
var bs58 = require("bs58");
var varint = require("./varint");
var var_int = require("./struct").var_int;
var bmcrypto = require("./crypto");
/**
@ -58,11 +58,11 @@ Address.decode = function(str) {
return getchecksum(data).then(function(realchecksum) {
assert(bufferEqual(checksum, realchecksum), "Bad checkum");
var decoded = varint.decode(data);
var decoded = var_int.decode(data);
var version = decoded.value;
data = decoded.rest;
decoded = varint.decode(data);
decoded = var_int.decode(data);
var stream = decoded.value;
var ripe = decoded.rest;
@ -185,8 +185,8 @@ Address.prototype.encode = function() {
var self = this;
return self.getRipe({short: true}).then(function(ripe) {
var data = Buffer.concat([
varint.encode(self.version),
varint.encode(self.stream),
var_int.encode(self.version),
var_int.encode(self.stream),
ripe,
]);
return getchecksum(data).then(function(checksum) {

2
lib/index.js
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@ -17,3 +17,5 @@ exports.Int64 = require("int64-native");
exports.Address = require("./address");
/** Working with WIF. */
exports.wif = require("./wif");
/** Core structures. */
exports.struct = require("./struct");

107
lib/struct.js Normal file
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@ -0,0 +1,107 @@
/**
* Implements core structures.
* @see {@link https://bitmessage.org/wiki/Protocol_specification#Common_structures}
* @module bitmessage/struct
*/
"use strict";
var assert = require("assert");
var bitmessage = require("./");
/**
* var_int.
* @see {@link https://bitmessage.org/wiki/Protocol_specification#Variable_length_integer}
*/
exports.var_int = {
/**
* Decode var_int.
* @param {Buffer} buf - Buffer that starts with encoded var_int
* @return {{value: (number|Int64), length: number, rest: number}}
* Decoded var_int structure.
*/
decode: function(buf) {
assert(buf.length > 0, "Empty buffer");
var value, length;
switch (buf[0]) {
case 253:
value = buf.readUInt16BE(1);
assert(value >= 253, "Impractical var_int");
length = 3;
break;
case 254:
value = buf.readUInt32BE(1);
assert(value >= 65536, "Impractical var_int");
length = 5;
break;
case 255:
var hi = buf.readUInt32BE(1);
assert(hi !== 0, "Impractical var_int");
var lo = buf.readUInt32BE(5);
value = new bitmessage.Int64(hi, lo);
length = 9;
break;
default:
value = buf[0];
length = 1;
}
var rest = buf.slice(length);
return {value: value, length: length, rest: rest};
},
/**
* Encode number into var_int.
* @param {(number|Int64|Buffer)} value - Input number
* @return {Buffer} Encoded var_int.
*/
encode: function(value) {
var buf, buf64, targetStart;
if (typeof value === "number") {
assert(value >= 0, "Value cannot be less than zero");
if (value < 253) {
buf = new Buffer([value]);
} else if (value < 65536) {
buf = new Buffer(3);
buf[0] = 253;
buf.writeUInt16BE(value, 1);
} else if (value < 4294967296) {
buf = new Buffer(5);
buf[0] = 254;
buf.writeUInt32BE(value, 1);
} else {
// Value may be inaccurate (max safe int = 2^53) but we will still
// try to convert it.
buf = new Buffer(9);
buf[0] = 255;
buf.writeUInt32BE(Math.floor(value / 4294967296), 1); // high32
buf.writeUInt32BE(value % 4294967296, 5); // low32
}
} else {
if (value.high32 && value.low32) {
// int64-native instance.
buf = new Buffer(9);
buf[0] = 255;
buf.writeUInt32BE(value.high32(), 1);
buf.writeUInt32BE(value.low32(), 5);
} else {
// Try to convert to buffer.
if (Buffer.isBuffer(value)) {
buf64 = value;
} else if (value.toBuffer) {
// node-int64 instance, rawBuffer = true (prevents extra buffer
// allocation since we copy it's value to new buffer anyway).
buf64 = value.toBuffer(true);
} else {
throw new Error("Value encode error");
}
assert(buf64.length <= 8, "Buffer too big");
buf = new Buffer(9);
buf.fill(0);
buf[0] = 255;
targetStart = 1 + (8 - buf64.length);
buf64.copy(buf, targetStart);
}
}
return buf;
},
};

101
lib/varint.js
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@ -1,101 +0,0 @@
/**
* Implements `var_int` encoding/decoding.
* @see {@link https://bitmessage.org/wiki/Protocol_specification#Variable_length_integer}
* @module bitmessage/varint
*/
"use strict";
var assert = require("assert");
var bitmessage = require("./");
/**
* Decode var_int.
* @param {Buffer} buf - Buffer that starts with encoded var_int
* @return {{value: (number|Int64), length: number, rest: number}}
* Decoded var_int structure.
*/
exports.decode = function(buf) {
assert(buf.length > 0, "Empty buffer");
var value, length;
switch (buf[0]) {
case 253:
value = buf.readUInt16BE(1);
assert(value >= 253, "Impractical var_int");
length = 3;
break;
case 254:
value = buf.readUInt32BE(1);
assert(value >= 65536, "Impractical var_int");
length = 5;
break;
case 255:
var hi = buf.readUInt32BE(1);
assert(hi !== 0, "Impractical var_int");
var lo = buf.readUInt32BE(5);
value = new bitmessage.Int64(hi, lo);
length = 9;
break;
default:
value = buf[0];
length = 1;
}
var rest = buf.slice(length);
return {value: value, length: length, rest: rest};
};
/**
* Encode number into var_int.
* @param {(number|Int64|Buffer)} value - Input number
* @return {Buffer} Encoded var_int.
*/
exports.encode = function(value) {
var buf, buf64, targetStart;
if (typeof value === "number") {
assert(value >= 0, "Value cannot be less than zero");
if (value < 253) {
buf = new Buffer([value]);
} else if (value < 65536) {
buf = new Buffer(3);
buf[0] = 253;
buf.writeUInt16BE(value, 1);
} else if (value < 4294967296) {
buf = new Buffer(5);
buf[0] = 254;
buf.writeUInt32BE(value, 1);
} else {
// Value may be inaccurate (max safe int = 2^53) but we will still
// try to convert it.
buf = new Buffer(9);
buf[0] = 255;
buf.writeUInt32BE(Math.floor(value / 4294967296), 1); // high32
buf.writeUInt32BE(value % 4294967296, 5); // low32
}
} else {
if (value.high32 && value.low32) {
// int64-native instance.
buf = new Buffer(9);
buf[0] = 255;
buf.writeUInt32BE(value.high32(), 1);
buf.writeUInt32BE(value.low32(), 5);
} else {
// Try to convert to buffer.
if (Buffer.isBuffer(value)) {
buf64 = value;
} else if (value.toBuffer) {
// node-int64 instance, rawBuffer = true (prevents extra buffer
// allocation since we copy it's value to new buffer anyway).
buf64 = value.toBuffer(true);
} else {
throw new Error("Value encode error");
}
assert(buf64.length <= 8, "Buffer too big");
buf = new Buffer(9);
buf.fill(0);
buf[0] = 255;
targetStart = 1 + (8 - buf64.length);
buf64.copy(buf, targetStart);
}
}
return buf;
};

42
test.js
View File

@ -7,52 +7,54 @@ var bitmessage = require("./lib");
var Int64 = bitmessage.Int64;
var Address = bitmessage.Address;
var wif = bitmessage.wif;
var varint = require("./lib/varint");
var var_int = bitmessage.struct.var_int;
var bmcrypto = require("./lib/crypto");
describe("var_int", function() {
describe("Core structures", function() {
describe("var_int", function() {
it("should decode", function() {
var res;
expect(varint.decode.bind(null, Buffer([]))).to.throw(Error);
expect(varint.decode.bind(null, Buffer("fd00", "hex"))).to.throw(Error);
expect(var_int.decode.bind(null, Buffer([]))).to.throw(Error);
expect(var_int.decode.bind(null, Buffer("fd00", "hex"))).to.throw(Error);
res = varint.decode(Buffer([123]));
res = var_int.decode(Buffer([123]));
expect(res.value).to.equal(123);
expect(res.length).to.equal(1);
expect(res.rest.toString("hex")).to.equal("")
res = varint.decode(Buffer("fd123456", "hex"));
res = var_int.decode(Buffer("fd123456", "hex"));
expect(res.value).to.equal(0x1234);
expect(res.length).to.equal(3);
expect(res.rest.toString("hex")).to.equal("56");
res = varint.decode(Buffer("fe1234567890", "hex"));
res = var_int.decode(Buffer("fe1234567890", "hex"));
expect(res.value).to.equal(0x12345678);
expect(res.length).to.equal(5);
expect(res.rest.toString("hex")).to.equal("90");
res = varint.decode(Buffer("ff0000001234567890", "hex"));
res = var_int.decode(Buffer("ff0000001234567890", "hex"));
expect(res.value == 0x1234567890).to.be.true;
expect(res.length).to.equal(9);
expect(res.rest.length).to.equal(0);
});
it("should check for lowest length on decode", function() {
expect(varint.decode.bind(null, Buffer("fd00fc", "hex"))).to.throw(Error);
expect(varint.decode.bind(null, Buffer("fe0000ffff", "hex"))).to.throw(Error);
expect(varint.decode.bind(null, Buffer("ff00000000ffffffff", "hex"))).to.throw(Error);
expect(var_int.decode.bind(null, Buffer("fd00fc", "hex"))).to.throw(Error);
expect(var_int.decode.bind(null, Buffer("fe0000ffff", "hex"))).to.throw(Error);
expect(var_int.decode.bind(null, Buffer("ff00000000ffffffff", "hex"))).to.throw(Error);
});
it("should encode", function() {
expect(varint.encode(123).toString("hex")).to.equal("7b");
expect(varint.encode(0x1234).toString("hex")).to.equal("fd1234");
expect(varint.encode(0x12345678).toString("hex")).to.equal("fe12345678");
expect(varint.encode(0x1234567890).toString("hex")).to.equal("ff0000001234567890");
expect(varint.encode(new Int64("0xffffffffffffffff")).toString("hex")).to.equal("ffffffffffffffffff");
expect(varint.encode(Buffer("1234567890", "hex")).toString("hex")).to.equal("ff0000001234567890");
expect(varint.encode.bind(null, -123)).to.throw(Error);
expect(varint.encode.bind(null, Buffer("123456789012345678", "hex"))).to.throw(Error);
expect(varint.encode.bind(null, "test")).to.throw(Error);
expect(var_int.encode(123).toString("hex")).to.equal("7b");
expect(var_int.encode(0x1234).toString("hex")).to.equal("fd1234");
expect(var_int.encode(0x12345678).toString("hex")).to.equal("fe12345678");
expect(var_int.encode(0x1234567890).toString("hex")).to.equal("ff0000001234567890");
expect(var_int.encode(new Int64("0xffffffffffffffff")).toString("hex")).to.equal("ffffffffffffffffff");
expect(var_int.encode(Buffer("1234567890", "hex")).toString("hex")).to.equal("ff0000001234567890");
expect(var_int.encode.bind(null, -123)).to.throw(Error);
expect(var_int.encode.bind(null, Buffer("123456789012345678", "hex"))).to.throw(Error);
expect(var_int.encode.bind(null, "test")).to.throw(Error);
});
});
});