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Fix JsonDecoder parsing of large floats with e+ scientific notation #49

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Merged
streamich merged 4 commits into from
Aug 8, 2025
Merged

Fix JsonDecoder parsing of large floats with e+ scientific notation #49

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2465b6d
Initial plan
Copilot Aug 8, 2025
a905e28
feat: initial analysis of JsonDecoder hardening issue
Copilot Aug 8, 2025
008bfd6
feat: fix JsonDecoder to handle e+ scientific notation and add large …
Copilot Aug 8, 2025
da645b0
style: 💄 run Prettier
streamich Aug 8, 2025
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42 changes: 42 additions & 0 deletions src/__tests__/fixtures/json/large-floats.ts
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Original file line number Diff line number Diff line change
@@ -0,0 +1,42 @@
/**
* Large floating point numbers and edge cases that should be handled correctly
* by JSON decoders, especially those with scientific notation (e+/e-).
*/
export default {
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@streamich streamich Aug 8, 2025

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Use these fixtures in JsonDecoder tests.

// Maximum finite representable value in JavaScript
maxValue: 1.7976931348623157e308,

// Same value with different notations
maxValueUppercase: '1.7976931348623157E+308',
maxValueImplicitPlus: '1.7976931348623157e308',

// Values that become Infinity
overflowToInfinity: 2e308,

// Medium range scientific notation
mediumLarge: 1.2345e50,
mediumSmall: 1.2345e-50,

// Very small numbers
verySmall: 5e-324,
smallestNormal: 2.2250738585072014e-308,

// Edge cases in arrays and objects
arrayWithLargeFloats: [1.7976931348623157e308, 2e308, 1.2345e-50],
objectWithLargeFloat: {
maxValue: 1.7976931348623157e308,
infinity: 2e308,
tiny: 5e-324,
},

// Mixed with other types
mixedData: {
numbers: [1, -1, 0, 1.7976931348623157e308, 5e-324],
strings: ['normal', 'with spaces'],
nested: {
largeFloat: 1.2345e100,
boolean: true,
nullValue: null,
},
},
};
32 changes: 16 additions & 16 deletions src/json/JsonDecoder.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -349,95 +349,95 @@ export class JsonDecoder implements BinaryJsonDecoder {
}
const c9 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(c1, c2, c3, c4, c5, c6, c7, c8, c9);
if (num !== num) throw new Error('Invalid JSON');
return num;
}
const c10 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(c1, c2, c3, c4, c5, c6, c7, c8, c9, c10);
if (num !== num) throw new Error('Invalid JSON');
return num;
}
const c11 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11);
if (num !== num) throw new Error('Invalid JSON');
return num;
}
const c12 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11, c12);
if (num !== num) throw new Error('Invalid JSON');
return num;
}
const c13 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11, c12, c13);
if (num !== num) throw new Error('Invalid JSON');
return num;
}
const c14 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11, c12, c13, c14);
if (num !== num) throw new Error('Invalid JSON');
return num;
}
const c15 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11, c12, c13, c14, c15);
if (num !== num) throw new Error('Invalid JSON');
return num;
}
const c16 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11, c12, c13, c14, c15, c16);
if (num !== num) throw new Error('Invalid JSON');
return num;
}
const c17 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11, c12, c13, c14, c15, c16, c17);
if (num !== num) throw new Error('Invalid JSON');
return num;
}
const c18 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11, c12, c13, c14, c15, c16, c17, c18);
if (num !== num) throw new Error('Invalid JSON');
return num;
}
const c19 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11, c12, c13, c14, c15, c16, c17, c18, c19);
if (num !== num) throw new Error('Invalid JSON');
return num;
}
const c20 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(
c1,
Expand Down Expand Up @@ -466,7 +466,7 @@ export class JsonDecoder implements BinaryJsonDecoder {
}
const c21 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(
c1,
Expand Down Expand Up @@ -496,7 +496,7 @@ export class JsonDecoder implements BinaryJsonDecoder {
}
const c22 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(
c1,
Expand Down Expand Up @@ -527,7 +527,7 @@ export class JsonDecoder implements BinaryJsonDecoder {
}
const c23 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(
c1,
Expand Down Expand Up @@ -559,7 +559,7 @@ export class JsonDecoder implements BinaryJsonDecoder {
}
const c24 = c;
c = uint8[x++];
if (!c || ((c < 45 || c > 57) && c !== 69 && c !== 101)) {
if (!c || ((c < 45 || c > 57) && c !== 43 && c !== 69 && c !== 101)) {
reader.x = x - 1;
const num = +fromCharCode(
c1,
Expand Down
64 changes: 64 additions & 0 deletions src/json/__tests__/JsonDecoder.spec.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -160,6 +160,70 @@ describe('number', () => {
const value = decoder.readAny();
expect(value).toBe(smallFloat);
});

test('large float with e+ notation - Number.MAX_VALUE', () => {
const data = Buffer.from('1.7976931348623157e+308', 'utf-8');
decoder.reader.reset(data);
const value = decoder.readAny();
expect(value).toBe(1.7976931348623157e308);
expect(value).toBe(Number.MAX_VALUE);
});

test('large float with E+ notation - uppercase', () => {
const data = Buffer.from('1.7976931348623157E+308', 'utf-8');
decoder.reader.reset(data);
const value = decoder.readAny();
expect(value).toBe(1.7976931348623157e308);
});

test('large float without explicit + sign', () => {
const data = Buffer.from('1.7976931348623157e308', 'utf-8');
decoder.reader.reset(data);
const value = decoder.readAny();
expect(value).toBe(1.7976931348623157e308);
});

test('infinity with e+ notation', () => {
const data = Buffer.from('2e+308', 'utf-8');
decoder.reader.reset(data);
const value = decoder.readAny();
expect(value).toBe(Infinity);
});

test('medium large float with e+ notation', () => {
const data = Buffer.from('1.2345e+50', 'utf-8');
decoder.reader.reset(data);
const value = decoder.readAny();
expect(value).toBe(1.2345e50);
});

test('very small float with e- notation', () => {
const data = Buffer.from('5e-324', 'utf-8');
decoder.reader.reset(data);
const value = decoder.readAny();
expect(value).toBe(5e-324);
});

test('smallest normal positive float', () => {
const data = Buffer.from('2.2250738585072014e-308', 'utf-8');
decoder.reader.reset(data);
const value = decoder.readAny();
expect(value).toBe(2.2250738585072014e-308);
});

test('large float in JSON array', () => {
const data = Buffer.from('[1.7976931348623157e+308]', 'utf-8');
decoder.reader.reset(data);
const value = decoder.readAny();
expect(value).toEqual([1.7976931348623157e308]);
});

test('large float in JSON object', () => {
const data = Buffer.from('{"value": 1.7976931348623157e+308}', 'utf-8');
decoder.reader.reset(data);
const value = decoder.readAny();
expect(value).toEqual({value: 1.7976931348623157e308});
});
});

describe('string', () => {
Expand Down