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fix: bug in slebEncode #368

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Merged
hansl merged 3 commits into from
Feb 11, 2020
Merged

fix: bug in slebEncode #368

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4cb8bf2
fix: bug in slebEncode
chenyan-dfinity Feb 9, 2020
f8d4907
fix
chenyan-dfinity Feb 9, 2020
3922cc0
fix
chenyan-dfinity Feb 9, 2020
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12 changes: 12 additions & 0 deletions src/userlib/js/src/idl.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -60,6 +60,12 @@ test('IDL encoding (int)', () => {
test_(IDL.Int, new BigNumber(0), '4449444c00017c00', 'Int');
test_(IDL.Int, new BigNumber(42), '4449444c00017c2a', 'Int');
test_(IDL.Int, new BigNumber(1234567890), '4449444c00017cd285d8cc04', 'Positive Int');
test_(
IDL.Int,
new BigNumber('60000000000000000'),
'4449444c00017c808098f4e9b5caea00',
'Positive BigInt',
);
test_(IDL.Int, new BigNumber(-1234567890), '4449444c00017caefaa7b37b', 'Negative Int');
test_(IDL.Opt(IDL.Int), new BigNumber(42), '4449444c016e7c0100012a', 'Nested Int');
testEncode(IDL.Opt(IDL.Int), 42, '4449444c016e7c0100012a', 'Nested Int (number)');
Expand All @@ -69,6 +75,12 @@ test('IDL encoding (nat)', () => {
// Nat
test_(IDL.Nat, new BigNumber(42), '4449444c00017d2a', 'Nat');
test_(IDL.Nat, new BigNumber(1234567890), '4449444c00017dd285d8cc04', 'Positive Nat');
test_(
IDL.Nat,
new BigNumber('60000000000000000'),
'4449444c00017d808098f4e9b5ca6a',
'Positive BigInt',
);
expect(() => IDL.encode([IDL.Nat], [-1])).toThrow(/Invalid Nat argument/);
testEncode(IDL.Opt(IDL.Int), 42, '4449444c016e7c0100012a', 'Nested Int (number)');
});
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18 changes: 18 additions & 0 deletions src/userlib/js/src/utils/leb128.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,12 @@ test('leb', () => {
expect(lebEncode(new BigNumber('1234567890abcdef1234567890abcdef', 16)).toString('hex')).toBe(
'ef9baf8589cf959a92deb7de8a929eabb424',
);
expect(
lebEncode(new BigNumber('2000000')).toString('hex'),
).toBe('80897a');
expect(
lebEncode(new BigNumber('60000000000000000')).toString('hex'),
).toBe('808098f4e9b5ca6a');

expect(lebDecode(new Pipe(Buffer.from([0]))).toNumber()).toBe(0);
expect(lebDecode(new Pipe(Buffer.from([1]))).toNumber()).toBe(1);
Expand All @@ -35,16 +41,28 @@ test('sleb', () => {
expect(slebEncode(-1).toString('hex')).toBe('7f');
expect(slebEncode(-123456).toString('hex')).toBe('c0bb78');
expect(slebEncode(42).toString('hex')).toBe('2a');
expect(slebEncode(new BigNumber('1234567890abcdef1234567890abcdef', 16)).toString('hex')).toBe(
'ef9baf8589cf959a92deb7de8a929eabb424',
);
expect(
slebEncode(new BigNumber('1234567890abcdef1234567890abcdef', 16).negated()).toString('hex'),
).toBe('91e4d0faf6b0eae5eda1c8a1f5ede1d4cb5b');
expect(
slebEncode(new BigNumber('2000000')).toString('hex'),
).toBe('8089fa00');
expect(
slebEncode(new BigNumber('60000000000000000')).toString('hex'),
).toBe('808098f4e9b5caea00');

expect(slebDecode(new Pipe(Buffer.from([0x7f]))).toNumber()).toBe(-1);
expect(slebDecode(new Pipe(Buffer.from([0xc0, 0xbb, 0x78]))).toNumber()).toBe(-123456);
expect(slebDecode(new Pipe(Buffer.from([0x2a]))).toNumber()).toBe(42);
expect(
slebDecode(new Pipe(Buffer.from('91e4d0faf6b0eae5eda1c8a1f5ede1d4cb5b', 'hex'))).toString(16),
).toBe('-1234567890abcdef1234567890abcdef');
expect(
slebDecode(new Pipe(Buffer.from('808098f4e9b5caea00', 'hex'))).toString(),
).toBe('60000000000000000');
});

test('IntLE', () => {
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55 changes: 25 additions & 30 deletions src/userlib/js/src/utils/leb128.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -11,20 +11,16 @@ export function lebEncode(value: number | BigNumber): Buffer {
if (value.lt(0)) {
throw new Error('Cannot leb encode negative values.');
}
if (value.eq(0)) {
// Clamp to 0.
return Buffer.from([0]);
}

const pipe = new Pipe();
while (value.gt(0)) {
while (true) {
const i = value.mod(0x80).toNumber();
value = value.idiv(0x80);

if (value.gt(0)) {
pipe.write([i | 0x80]);
} else {
if (value.eq(0)) {
pipe.write([i]);
break;
} else {
pipe.write([i | 0x80]);
}
}

Expand All @@ -49,35 +45,34 @@ export function slebEncode(value: BigNumber | number): Buffer {
if (typeof value === 'number') {
value = new BigNumber(value);
}
value = value.integerValue();

if (value.gte(0)) {
return lebEncode(value);
}

value = value
.abs()
.integerValue()
.minus(1);

// We need to special case 0, as it would return an empty buffer. Since
// we removed 1 above, this is really -1.
if (value.eq(0)) {
return Buffer.from([0x7f]);
const isNeg = value.lt(0);
if (isNeg) {
value = value.abs().minus(1);
}

const pipe = new Pipe();
while (value.gt(0)) {
// We swap the bits here again, and remove 1 to do two's complement.
const i = 0x80 - value.mod(0x80).toNumber() - 1;
while (true) {
const i = getLowerBytes(value);
value = value.idiv(0x80);

if (value.gt(0)) {
pipe.write([i | 0x80]);
} else {
if ((isNeg && value.eq(0) && (i & 0x40) !== 0) ||
(!isNeg && value.eq(0) && (i & 0x40) === 0)) {
pipe.write([i]);
break;
} else {
pipe.write([i | 0x80]);
}
}

function getLowerBytes(num: BigNumber): number {
const bytes = num.mod(0x80).toNumber();
if (isNeg) {
// We swap the bits here again, and remove 1 to do two's complement.
return 0x80 - bytes - 1;
} else {
return bytes;
}
}
return pipe.buffer;
}

Expand Down