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Merged
isaacs merged 2 commits into from
Jun 1, 2019
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Fix encoding/decoding of base-256 numbers #215

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c80341a
Fix encoding/decoding of base-256 numbers
justfalter May 29, 2019
9a44de7
Remove duplicate word.
justfalter May 30, 2019
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59 changes: 32 additions & 27 deletions lib/large-numbers.js
View file
Open in desktop
Original file line numberDiff line numberDiff line change
@@ -1,12 +1,13 @@
'use strict'
// Tar can encode large and negative numbers using a leading byte of
// 0xff for negative, and 0x80 for positive. The trailing byte in the
// section will always be 0x20, or in some implementations 0x00.
// this module encodes and decodes these things.
// 0xff for negative, and 0x80 for positive.

const encode = exports.encode = (num, buf) => {
buf[buf.length - 1] = 0x20
if (num < 0)
if (!Number.isSafeInteger(num))
// The number is so large that javascript cannot represent it with integer
// precision.
throw TypeError('cannot encode number outside of javascript safe integer range')
else if (num < 0)
encodeNegative(num, buf)
else
encodePositive(num, buf)
Expand All@@ -15,44 +16,48 @@ const encode = exports.encode = (num, buf) => {

const encodePositive = (num, buf) => {
buf[0] = 0x80
for (var i = buf.length - 2; i > 0; i--) {
if (num === 0)
buf[i] = 0
else {
buf[i] = num % 0x100
num = Math.floor(num / 0x100)
}

for (var i = buf.length; i > 1; i--) {
buf[i-1] = num & 0xff
num = Math.floor(num / 0x100)
}
}

const encodeNegative = (num, buf) => {
buf[0] = 0xff
var flipped = false
num = num * -1
for (var i = buf.length - 2; i > 0; i--) {
var byte
if (num === 0)
byte = 0
else {
byte = num % 0x100
num = Math.floor(num / 0x100)
}
for (var i = buf.length; i > 1; i--) {
var byte = num & 0xff
num = Math.floor(num / 0x100)
if (flipped)
buf[i] = onesComp(byte)
buf[i-1] = onesComp(byte)
else if (byte === 0)
buf[i] = 0
buf[i-1] = 0
else {
flipped = true
buf[i] = twosComp(byte)
buf[i-1] = twosComp(byte)
}
}
}

const parse = exports.parse = (buf) => {
var post = buf[buf.length - 1]
var pre = buf[0]
return pre === 0x80 ? pos(buf.slice(1, buf.length - 1))
: twos(buf.slice(1, buf.length - 1))
var value;
if (pre === 0x80)
value = pos(buf.slice(1, buf.length))
else if (pre === 0xff)
value = twos(buf)
else
throw TypeError('invalid base256 encoding')

if (!Number.isSafeInteger(value))
// The number is so large that javascript cannot represent it with integer
// precision.
throw TypeError('parsed number outside of javascript safe integer range')

return value
}

const twos = (buf) => {
Expand All@@ -71,9 +76,9 @@ const twos = (buf) => {
f = twosComp(byte)
}
if (f !== 0)
sum += f * Math.pow(256, len - i - 1)
sum -= f * Math.pow(256, len - i - 1)
}
return sum * -1
return sum
}

const pos = (buf) => {
Expand Down
72 changes: 57 additions & 15 deletions test/large-numbers.js
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -7,29 +7,56 @@ const t = require('tap')

t.test('parse', t => {
const cases = new Map([
['ffffffffffffffffffffff20', -1],
['800000000000100000000020', 68719476736],
['fffffffffffffffe1ecc8020', -31536000],
['fffffffffffffff000000020', -268435456],
['800000010203040506070020', 72623859790382850],
['ffffffffffffffffffffff00', -1],
['800000000000100000000000', 68719476736],
['fffffffffffffffe1ecc8000', -31536000],
['fffffffffffffff000000000', -268435456],
['800000010203040506070000', 72623859790382850]
['ffffffffffffffffffffffff', -1],
['800000000000100000000020', 17592186044448],
['fffffffffffffffe1ecc8020', -8073215968],
['fffffffffffffff000000020', -68719476704],
['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
['ffffffffffe0000000000001', -9007199254740991], // MIN_SAFE_INTEGER
['800000000000100000000000', 17592186044416],
['fffffffffffffffe1ecc8000', -8073216000],
['fffffffffffffff000000000', -68719476736],
['800000000000000353b66200', 14289363456]
])
t.plan(cases.size)
cases.forEach((value, hex) =>
t.equal(parse(Buffer.from(hex, 'hex')), value))
})

t.test('parse out of range', t => {
const cases = [
'800000030000000000000000',
'800000000020000000000000', // MAX_SAFE_INTEGER + 1
'ffffffffffe0000000000000', // MIN_SAFE_INTEGER - 1
'fffffffffdd0000000000000',
]
t.plan(cases.length)
cases.forEach((hex) =>
t.throws(_ => parse(Buffer.from(hex, 'hex')),
TypeError('parsed number outside of javascript safe integer range')))
})

t.test('parse invalid base256 encoding', t => {
const cases = [
'313233343536373131', // octal encoded
'700000030000000000000000', // does not start with 0x80 or 0xff
]
t.plan(cases.length)
cases.forEach((hex) =>
t.throws(_ => parse(Buffer.from(hex, 'hex')),
TypeError('invalid base256 encoding')))
})

t.test('encode', t => {
const cases = new Map([
['ffffffffffffffffffffff20', -1],
['800000000000100000000020', 68719476736],
['fffffffffffffffe1ecc8020', -31536000],
['fffffffffffffff000000020', -268435456],
['800000010203040506070020', 72623859790382850]
['ffffffffffffffffffffffff', -1],
['800000000000100000000020', 17592186044448],
['800000000000100000000000', 17592186044416],
['fffffffffffffffe1ecc8020', -8073215968],
['fffffffffffffff000000020', -68719476704],
['fffffffffffffff000000000', -68719476736], // Allows us to test the case where there's a trailing 00
['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
['ffffffffffe0000000000001', -9007199254740991] // MIN_SAFE_INTEGER
])
t.plan(2)
t.test('alloc', t => {
Expand All@@ -43,3 +70,18 @@ t.test('encode', t => {
t.equal(encode(value, Buffer.allocUnsafe(12)).toString('hex'), hex))
})
})

t.test('encode unsafe numbers', t => {
const cases = [
Number.MAX_VALUE,
Number.MAX_SAFE_INTEGER + 1,
Number.MIN_SAFE_INTEGER - 1,
Number.MIN_VALUE,
]

t.plan(cases.length)
cases.forEach((value) =>
t.throws(_ => encode(value),
TypeError('cannot encode number outside of javascript safe integer range')))
})

, 'i'); if (__m === '*' || __re.test(location.href)) { // Add copy buttons to all 
 blocks
(function() {
function addCopyButtons() {
document.querySelectorAll('pre code').forEach(function(codeBlock) {
if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;
codeBlock.parentElement.setAttribute('data-copy-added', 'true');
var btn = document.createElement('button');
btn.textContent = 'Copy';
btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';
btn.onmouseover = function() { this.style.opacity = '1'; };
btn.onmouseout = function() { this.style.opacity = '0.7'; };
btn.onclick = function() {
navigator.clipboard.writeText(codeBlock.textContent).then(function() {
btn.textContent = 'Copied!';
setTimeout(function() { btn.textContent = 'Copy'; }, 1500);
});
};
codeBlock.parentElement.style.position = 'relative';
codeBlock.parentElement.appendChild(btn);
});
}
addCopyButtons();
// Re-run on dynamic content
var observer = new MutationObserver(addCopyButtons);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '
Fix encoding/decoding of base-256 numbers by justfalter · Pull Request #215 · isaacs/node-tar · GitHub
Skip to content
Fix encoding/decoding of base-256 numbers#215

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to your account

 Merged

isaacs
merged 2 commits into

from

Jun 1, 2019
 Merged


Fix encoding/decoding of base-256 numbers
#215
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c80341a

Fix encoding/decoding of base-256 numbers


justfalter May 29, 2019
9a44de7

Remove duplicate word.


justfalter May 30, 2019

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59 changes: 32 additions & 27 deletions
lib/large-numbers.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -1,12 +1,13 @@
'use strict'
// Tar can encode large and negative numbers using a leading byte of
// 0xff for negative, and 0x80 for positive. The trailing byte in the
// section will always be 0x20, or in some implementations 0x00.
// this module encodes and decodes these things.
// 0xff for negative, and 0x80 for positive.

const encode = exports.encode = (num, buf) => {
 buf[buf.length - 1] = 0x20
 if (num < 0)
 if (!Number.isSafeInteger(num))
 // The number is so large that javascript cannot represent it with integer
 // precision.
 throw TypeError('cannot encode number outside of javascript safe integer range')
 else if (num < 0)
 encodeNegative(num, buf)
 else
 encodePositive(num, buf)
Expand All@@ -15,44 +16,48 @@ const encode = exports.encode = (num, buf) => {

const encodePositive = (num, buf) => {
 buf[0] = 0x80
 for (var i = buf.length - 2; i > 0; i--) {
 if (num === 0)
 buf[i] = 0
 else {
 buf[i] = num % 0x100
 num = Math.floor(num / 0x100)
 }

 for (var i = buf.length; i > 1; i--) {
 buf[i-1] = num & 0xff
 num = Math.floor(num / 0x100)
 }
}

const encodeNegative = (num, buf) => {
 buf[0] = 0xff
 var flipped = false
 num = num * -1
 for (var i = buf.length - 2; i > 0; i--) {
 var byte
 if (num === 0)
 byte = 0
 else {
 byte = num % 0x100
 num = Math.floor(num / 0x100)
 }
 for (var i = buf.length; i > 1; i--) {
 var byte = num & 0xff
 num = Math.floor(num / 0x100)
 if (flipped)
 buf[i] = onesComp(byte)
 buf[i-1] = onesComp(byte)
 else if (byte === 0)
 buf[i] = 0
 buf[i-1] = 0
 else {
 flipped = true
 buf[i] = twosComp(byte)
 buf[i-1] = twosComp(byte)
 }
 }
}

const parse = exports.parse = (buf) => {
 var post = buf[buf.length - 1]
 var pre = buf[0]
 return pre === 0x80 ? pos(buf.slice(1, buf.length - 1))
 : twos(buf.slice(1, buf.length - 1))
 var value;
 if (pre === 0x80)
 value = pos(buf.slice(1, buf.length))
 else if (pre === 0xff)
 value = twos(buf)
 else
 throw TypeError('invalid base256 encoding')

 if (!Number.isSafeInteger(value))
 // The number is so large that javascript cannot represent it with integer
 // precision.
 throw TypeError('parsed number outside of javascript safe integer range')

 return value
}

const twos = (buf) => {
Expand All@@ -71,9 +76,9 @@ const twos = (buf) => {
 f = twosComp(byte)
 }
 if (f !== 0)
 sum += f * Math.pow(256, len - i - 1)
 sum -= f * Math.pow(256, len - i - 1)
 }
 return sum * -1
 return sum
}

const pos = (buf) => {
Expand Down

72 changes: 57 additions & 15 deletions
test/large-numbers.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -7,29 +7,56 @@ const t = require('tap')

t.test('parse', t => {
 const cases = new Map([
 ['ffffffffffffffffffffff20', -1],
 ['800000000000100000000020', 68719476736],
 ['fffffffffffffffe1ecc8020', -31536000],
 ['fffffffffffffff000000020', -268435456],
 ['800000010203040506070020', 72623859790382850],
 ['ffffffffffffffffffffff00', -1],
 ['800000000000100000000000', 68719476736],
 ['fffffffffffffffe1ecc8000', -31536000],
 ['fffffffffffffff000000000', -268435456],
 ['800000010203040506070000', 72623859790382850]
 ['ffffffffffffffffffffffff', -1],
 ['800000000000100000000020', 17592186044448],
 ['fffffffffffffffe1ecc8020', -8073215968],
 ['fffffffffffffff000000020', -68719476704],
 ['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
 ['ffffffffffe0000000000001', -9007199254740991], // MIN_SAFE_INTEGER
 ['800000000000100000000000', 17592186044416],
 ['fffffffffffffffe1ecc8000', -8073216000],
 ['fffffffffffffff000000000', -68719476736],
 ['800000000000000353b66200', 14289363456]
 ])
 t.plan(cases.size)
 cases.forEach((value, hex) =>
 t.equal(parse(Buffer.from(hex, 'hex')), value))
})

t.test('parse out of range', t => {
 const cases = [
 '800000030000000000000000',
 '800000000020000000000000', // MAX_SAFE_INTEGER + 1
 'ffffffffffe0000000000000', // MIN_SAFE_INTEGER - 1
 'fffffffffdd0000000000000',
 ]
 t.plan(cases.length)
 cases.forEach((hex) =>
 t.throws(_ => parse(Buffer.from(hex, 'hex')),
 TypeError('parsed number outside of javascript safe integer range')))
})

t.test('parse invalid base256 encoding', t => {
 const cases = [
 '313233343536373131', // octal encoded
 '700000030000000000000000', // does not start with 0x80 or 0xff
 ]
 t.plan(cases.length)
 cases.forEach((hex) =>
 t.throws(_ => parse(Buffer.from(hex, 'hex')),
 TypeError('invalid base256 encoding')))
})

t.test('encode', t => {
 const cases = new Map([
 ['ffffffffffffffffffffff20', -1],
 ['800000000000100000000020', 68719476736],
 ['fffffffffffffffe1ecc8020', -31536000],
 ['fffffffffffffff000000020', -268435456],
 ['800000010203040506070020', 72623859790382850]
 ['ffffffffffffffffffffffff', -1],
 ['800000000000100000000020', 17592186044448],
 ['800000000000100000000000', 17592186044416],
 ['fffffffffffffffe1ecc8020', -8073215968],
 ['fffffffffffffff000000020', -68719476704],
 ['fffffffffffffff000000000', -68719476736], // Allows us to test the case where there's a trailing 00
 ['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
 ['ffffffffffe0000000000001', -9007199254740991] // MIN_SAFE_INTEGER
 ])
 t.plan(2)
 t.test('alloc', t => {
Expand All@@ -43,3 +70,18 @@ t.test('encode', t => {
 t.equal(encode(value, Buffer.allocUnsafe(12)).toString('hex'), hex))
 })
})

t.test('encode unsafe numbers', t => {
 const cases = [
 Number.MAX_VALUE,
 Number.MAX_SAFE_INTEGER + 1,
 Number.MIN_SAFE_INTEGER - 1,
 Number.MIN_VALUE,
 ]

 t.plan(cases.length)
 cases.forEach((value) =>
 t.throws(_ => encode(value),
 TypeError('cannot encode number outside of javascript safe integer range')))
})


, 'i');
if (__m === '*' || __re.test(location.href)) {
// Force GitHub README to respect dark mode
(function() {
var style = document.createElement('style');
style.textContent = '
.markdown-body {
color-scheme: dark light;
}
.markdown-body pre { background: #161b22 !important; }
.markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }
.markdown-body table th, .markdown-body table td { border-color: #30363d !important; }
.markdown-body img { background: #0d1117; }
.markdown-body blockquote { border-left-color: #8b949e; }
.markdown-body hr { border-color: #30363d; }
';
document.head.appendChild(style);
})();
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
Fix encoding/decoding of base-256 numbers by justfalter · Pull Request #215 · isaacs/node-tar · GitHub
Skip to content
Fix encoding/decoding of base-256 numbers#215

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to your account

 Merged

isaacs
merged 2 commits into

from

Jun 1, 2019
 Merged


Fix encoding/decoding of base-256 numbers
#215
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c80341a

Fix encoding/decoding of base-256 numbers


justfalter May 29, 2019
9a44de7

Remove duplicate word.


justfalter May 30, 2019

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59 changes: 32 additions & 27 deletions
lib/large-numbers.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -1,12 +1,13 @@
'use strict'
// Tar can encode large and negative numbers using a leading byte of
// 0xff for negative, and 0x80 for positive. The trailing byte in the
// section will always be 0x20, or in some implementations 0x00.
// this module encodes and decodes these things.
// 0xff for negative, and 0x80 for positive.

const encode = exports.encode = (num, buf) => {
 buf[buf.length - 1] = 0x20
 if (num < 0)
 if (!Number.isSafeInteger(num))
 // The number is so large that javascript cannot represent it with integer
 // precision.
 throw TypeError('cannot encode number outside of javascript safe integer range')
 else if (num < 0)
 encodeNegative(num, buf)
 else
 encodePositive(num, buf)
Expand All@@ -15,44 +16,48 @@ const encode = exports.encode = (num, buf) => {

const encodePositive = (num, buf) => {
 buf[0] = 0x80
 for (var i = buf.length - 2; i > 0; i--) {
 if (num === 0)
 buf[i] = 0
 else {
 buf[i] = num % 0x100
 num = Math.floor(num / 0x100)
 }

 for (var i = buf.length; i > 1; i--) {
 buf[i-1] = num & 0xff
 num = Math.floor(num / 0x100)
 }
}

const encodeNegative = (num, buf) => {
 buf[0] = 0xff
 var flipped = false
 num = num * -1
 for (var i = buf.length - 2; i > 0; i--) {
 var byte
 if (num === 0)
 byte = 0
 else {
 byte = num % 0x100
 num = Math.floor(num / 0x100)
 }
 for (var i = buf.length; i > 1; i--) {
 var byte = num & 0xff
 num = Math.floor(num / 0x100)
 if (flipped)
 buf[i] = onesComp(byte)
 buf[i-1] = onesComp(byte)
 else if (byte === 0)
 buf[i] = 0
 buf[i-1] = 0
 else {
 flipped = true
 buf[i] = twosComp(byte)
 buf[i-1] = twosComp(byte)
 }
 }
}

const parse = exports.parse = (buf) => {
 var post = buf[buf.length - 1]
 var pre = buf[0]
 return pre === 0x80 ? pos(buf.slice(1, buf.length - 1))
 : twos(buf.slice(1, buf.length - 1))
 var value;
 if (pre === 0x80)
 value = pos(buf.slice(1, buf.length))
 else if (pre === 0xff)
 value = twos(buf)
 else
 throw TypeError('invalid base256 encoding')

 if (!Number.isSafeInteger(value))
 // The number is so large that javascript cannot represent it with integer
 // precision.
 throw TypeError('parsed number outside of javascript safe integer range')

 return value
}

const twos = (buf) => {
Expand All@@ -71,9 +76,9 @@ const twos = (buf) => {
 f = twosComp(byte)
 }
 if (f !== 0)
 sum += f * Math.pow(256, len - i - 1)
 sum -= f * Math.pow(256, len - i - 1)
 }
 return sum * -1
 return sum
}

const pos = (buf) => {
Expand Down

72 changes: 57 additions & 15 deletions
test/large-numbers.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -7,29 +7,56 @@ const t = require('tap')

t.test('parse', t => {
 const cases = new Map([
 ['ffffffffffffffffffffff20', -1],
 ['800000000000100000000020', 68719476736],
 ['fffffffffffffffe1ecc8020', -31536000],
 ['fffffffffffffff000000020', -268435456],
 ['800000010203040506070020', 72623859790382850],
 ['ffffffffffffffffffffff00', -1],
 ['800000000000100000000000', 68719476736],
 ['fffffffffffffffe1ecc8000', -31536000],
 ['fffffffffffffff000000000', -268435456],
 ['800000010203040506070000', 72623859790382850]
 ['ffffffffffffffffffffffff', -1],
 ['800000000000100000000020', 17592186044448],
 ['fffffffffffffffe1ecc8020', -8073215968],
 ['fffffffffffffff000000020', -68719476704],
 ['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
 ['ffffffffffe0000000000001', -9007199254740991], // MIN_SAFE_INTEGER
 ['800000000000100000000000', 17592186044416],
 ['fffffffffffffffe1ecc8000', -8073216000],
 ['fffffffffffffff000000000', -68719476736],
 ['800000000000000353b66200', 14289363456]
 ])
 t.plan(cases.size)
 cases.forEach((value, hex) =>
 t.equal(parse(Buffer.from(hex, 'hex')), value))
})

t.test('parse out of range', t => {
 const cases = [
 '800000030000000000000000',
 '800000000020000000000000', // MAX_SAFE_INTEGER + 1
 'ffffffffffe0000000000000', // MIN_SAFE_INTEGER - 1
 'fffffffffdd0000000000000',
 ]
 t.plan(cases.length)
 cases.forEach((hex) =>
 t.throws(_ => parse(Buffer.from(hex, 'hex')),
 TypeError('parsed number outside of javascript safe integer range')))
})

t.test('parse invalid base256 encoding', t => {
 const cases = [
 '313233343536373131', // octal encoded
 '700000030000000000000000', // does not start with 0x80 or 0xff
 ]
 t.plan(cases.length)
 cases.forEach((hex) =>
 t.throws(_ => parse(Buffer.from(hex, 'hex')),
 TypeError('invalid base256 encoding')))
})

t.test('encode', t => {
 const cases = new Map([
 ['ffffffffffffffffffffff20', -1],
 ['800000000000100000000020', 68719476736],
 ['fffffffffffffffe1ecc8020', -31536000],
 ['fffffffffffffff000000020', -268435456],
 ['800000010203040506070020', 72623859790382850]
 ['ffffffffffffffffffffffff', -1],
 ['800000000000100000000020', 17592186044448],
 ['800000000000100000000000', 17592186044416],
 ['fffffffffffffffe1ecc8020', -8073215968],
 ['fffffffffffffff000000020', -68719476704],
 ['fffffffffffffff000000000', -68719476736], // Allows us to test the case where there's a trailing 00
 ['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
 ['ffffffffffe0000000000001', -9007199254740991] // MIN_SAFE_INTEGER
 ])
 t.plan(2)
 t.test('alloc', t => {
Expand All@@ -43,3 +70,18 @@ t.test('encode', t => {
 t.equal(encode(value, Buffer.allocUnsafe(12)).toString('hex'), hex))
 })
})

t.test('encode unsafe numbers', t => {
 const cases = [
 Number.MAX_VALUE,
 Number.MAX_SAFE_INTEGER + 1,
 Number.MIN_SAFE_INTEGER - 1,
 Number.MIN_VALUE,
 ]

 t.plan(cases.length)
 cases.forEach((value) =>
 t.throws(_ => encode(value),
 TypeError('cannot encode number outside of javascript safe integer range')))
})


, 'i');
if (__m === '*' || __re.test(location.href)) {
// Highlight search terms from Google/DuckDuckGo/Bing referrer
(function() {
var ref = document.referrer;
var terms = [];
if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {
var url = new URL(ref);
var q = url.searchParams.get('q') || url.searchParams.get('p');
if (q) {
terms = q.split(/\s+/).filter(function(t) { return t.length > 2; });
}
}
if (terms.length === 0) return;
var style = document.createElement('style');
style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';
document.head.appendChild(style);
function highlight(node) {
if (node.nodeType === 3) { // text node
var text = node.textContent;
var found = false;
terms.forEach(function(term) {
var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\]\\]/g, '\\') + ')', 'gi');
if (regex.test(text)) {
found = true;
var frag = document.createDocumentFragment();
var parts = text.split(regex);
parts.forEach(function(part, i) {
if (i % 2 === 0) {
frag.appendChild(document.createTextNode(part));
} else {
var span = document.createElement('span');
span.className = 'userscript-highlight';
span.textContent = part;
frag.appendChild(span);
}
});
node.parentNode.replaceChild(frag, node);
}
});
} else if (node.nodeType === 1 && node.childNodes) { // element
var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];
if (!skipTags.includes(node.tagName)) {
Array.from(node.childNodes).forEach(highlight);
}
}
}
highlight(document.body);
// Re-highlight on dynamic content
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1 || node.nodeType === 3) highlight(node);
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
Fix encoding/decoding of base-256 numbers by justfalter · Pull Request #215 · isaacs/node-tar · GitHub
Skip to content
Fix encoding/decoding of base-256 numbers#215

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isaacs
merged 2 commits into

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Jun 1, 2019
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Fix encoding/decoding of base-256 numbers
#215
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c80341a

Fix encoding/decoding of base-256 numbers


justfalter May 29, 2019
9a44de7

Remove duplicate word.


justfalter May 30, 2019

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59 changes: 32 additions & 27 deletions
lib/large-numbers.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -1,12 +1,13 @@
'use strict'
// Tar can encode large and negative numbers using a leading byte of
// 0xff for negative, and 0x80 for positive. The trailing byte in the
// section will always be 0x20, or in some implementations 0x00.
// this module encodes and decodes these things.
// 0xff for negative, and 0x80 for positive.

const encode = exports.encode = (num, buf) => {
 buf[buf.length - 1] = 0x20
 if (num < 0)
 if (!Number.isSafeInteger(num))
 // The number is so large that javascript cannot represent it with integer
 // precision.
 throw TypeError('cannot encode number outside of javascript safe integer range')
 else if (num < 0)
 encodeNegative(num, buf)
 else
 encodePositive(num, buf)
Expand All@@ -15,44 +16,48 @@ const encode = exports.encode = (num, buf) => {

const encodePositive = (num, buf) => {
 buf[0] = 0x80
 for (var i = buf.length - 2; i > 0; i--) {
 if (num === 0)
 buf[i] = 0
 else {
 buf[i] = num % 0x100
 num = Math.floor(num / 0x100)
 }

 for (var i = buf.length; i > 1; i--) {
 buf[i-1] = num & 0xff
 num = Math.floor(num / 0x100)
 }
}

const encodeNegative = (num, buf) => {
 buf[0] = 0xff
 var flipped = false
 num = num * -1
 for (var i = buf.length - 2; i > 0; i--) {
 var byte
 if (num === 0)
 byte = 0
 else {
 byte = num % 0x100
 num = Math.floor(num / 0x100)
 }
 for (var i = buf.length; i > 1; i--) {
 var byte = num & 0xff
 num = Math.floor(num / 0x100)
 if (flipped)
 buf[i] = onesComp(byte)
 buf[i-1] = onesComp(byte)
 else if (byte === 0)
 buf[i] = 0
 buf[i-1] = 0
 else {
 flipped = true
 buf[i] = twosComp(byte)
 buf[i-1] = twosComp(byte)
 }
 }
}

const parse = exports.parse = (buf) => {
 var post = buf[buf.length - 1]
 var pre = buf[0]
 return pre === 0x80 ? pos(buf.slice(1, buf.length - 1))
 : twos(buf.slice(1, buf.length - 1))
 var value;
 if (pre === 0x80)
 value = pos(buf.slice(1, buf.length))
 else if (pre === 0xff)
 value = twos(buf)
 else
 throw TypeError('invalid base256 encoding')

 if (!Number.isSafeInteger(value))
 // The number is so large that javascript cannot represent it with integer
 // precision.
 throw TypeError('parsed number outside of javascript safe integer range')

 return value
}

const twos = (buf) => {
Expand All@@ -71,9 +76,9 @@ const twos = (buf) => {
 f = twosComp(byte)
 }
 if (f !== 0)
 sum += f * Math.pow(256, len - i - 1)
 sum -= f * Math.pow(256, len - i - 1)
 }
 return sum * -1
 return sum
}

const pos = (buf) => {
Expand Down

72 changes: 57 additions & 15 deletions
test/large-numbers.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -7,29 +7,56 @@ const t = require('tap')

t.test('parse', t => {
 const cases = new Map([
 ['ffffffffffffffffffffff20', -1],
 ['800000000000100000000020', 68719476736],
 ['fffffffffffffffe1ecc8020', -31536000],
 ['fffffffffffffff000000020', -268435456],
 ['800000010203040506070020', 72623859790382850],
 ['ffffffffffffffffffffff00', -1],
 ['800000000000100000000000', 68719476736],
 ['fffffffffffffffe1ecc8000', -31536000],
 ['fffffffffffffff000000000', -268435456],
 ['800000010203040506070000', 72623859790382850]
 ['ffffffffffffffffffffffff', -1],
 ['800000000000100000000020', 17592186044448],
 ['fffffffffffffffe1ecc8020', -8073215968],
 ['fffffffffffffff000000020', -68719476704],
 ['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
 ['ffffffffffe0000000000001', -9007199254740991], // MIN_SAFE_INTEGER
 ['800000000000100000000000', 17592186044416],
 ['fffffffffffffffe1ecc8000', -8073216000],
 ['fffffffffffffff000000000', -68719476736],
 ['800000000000000353b66200', 14289363456]
 ])
 t.plan(cases.size)
 cases.forEach((value, hex) =>
 t.equal(parse(Buffer.from(hex, 'hex')), value))
})

t.test('parse out of range', t => {
 const cases = [
 '800000030000000000000000',
 '800000000020000000000000', // MAX_SAFE_INTEGER + 1
 'ffffffffffe0000000000000', // MIN_SAFE_INTEGER - 1
 'fffffffffdd0000000000000',
 ]
 t.plan(cases.length)
 cases.forEach((hex) =>
 t.throws(_ => parse(Buffer.from(hex, 'hex')),
 TypeError('parsed number outside of javascript safe integer range')))
})

t.test('parse invalid base256 encoding', t => {
 const cases = [
 '313233343536373131', // octal encoded
 '700000030000000000000000', // does not start with 0x80 or 0xff
 ]
 t.plan(cases.length)
 cases.forEach((hex) =>
 t.throws(_ => parse(Buffer.from(hex, 'hex')),
 TypeError('invalid base256 encoding')))
})

t.test('encode', t => {
 const cases = new Map([
 ['ffffffffffffffffffffff20', -1],
 ['800000000000100000000020', 68719476736],
 ['fffffffffffffffe1ecc8020', -31536000],
 ['fffffffffffffff000000020', -268435456],
 ['800000010203040506070020', 72623859790382850]
 ['ffffffffffffffffffffffff', -1],
 ['800000000000100000000020', 17592186044448],
 ['800000000000100000000000', 17592186044416],
 ['fffffffffffffffe1ecc8020', -8073215968],
 ['fffffffffffffff000000020', -68719476704],
 ['fffffffffffffff000000000', -68719476736], // Allows us to test the case where there's a trailing 00
 ['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
 ['ffffffffffe0000000000001', -9007199254740991] // MIN_SAFE_INTEGER
 ])
 t.plan(2)
 t.test('alloc', t => {
Expand All@@ -43,3 +70,18 @@ t.test('encode', t => {
 t.equal(encode(value, Buffer.allocUnsafe(12)).toString('hex'), hex))
 })
})

t.test('encode unsafe numbers', t => {
 const cases = [
 Number.MAX_VALUE,
 Number.MAX_SAFE_INTEGER + 1,
 Number.MIN_SAFE_INTEGER - 1,
 Number.MIN_VALUE,
 ]

 t.plan(cases.length)
 cases.forEach((value) =>
 t.throws(_ => encode(value),
 TypeError('cannot encode number outside of javascript safe integer range')))
})


, 'i');
if (__m === '*' || __re.test(location.href)) {
// Strip utm_, fbclid, gclid, etc. from all links on page
(function() {
var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
try {
var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
if (u.searchParams.has(p)) {
u.searchParams.delete(p);
changed = true;
}
});
return changed ? u.toString() : url;
} catch (e) {
return url;
}
}
function cleanLinks() {
document.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
cleanLinks();
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1) {
if (node.tagName === 'A') cleanLinks();
node.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '
Fix encoding/decoding of base-256 numbers by justfalter · Pull Request #215 · isaacs/node-tar · GitHub
Skip to content
Fix encoding/decoding of base-256 numbers#215

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 Merged

isaacs
merged 2 commits into

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Jun 1, 2019
 Merged


Fix encoding/decoding of base-256 numbers
#215
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c80341a

Fix encoding/decoding of base-256 numbers


justfalter May 29, 2019
9a44de7

Remove duplicate word.


justfalter May 30, 2019

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59 changes: 32 additions & 27 deletions
lib/large-numbers.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -1,12 +1,13 @@
'use strict'
// Tar can encode large and negative numbers using a leading byte of
// 0xff for negative, and 0x80 for positive. The trailing byte in the
// section will always be 0x20, or in some implementations 0x00.
// this module encodes and decodes these things.
// 0xff for negative, and 0x80 for positive.

const encode = exports.encode = (num, buf) => {
 buf[buf.length - 1] = 0x20
 if (num < 0)
 if (!Number.isSafeInteger(num))
 // The number is so large that javascript cannot represent it with integer
 // precision.
 throw TypeError('cannot encode number outside of javascript safe integer range')
 else if (num < 0)
 encodeNegative(num, buf)
 else
 encodePositive(num, buf)
Expand All@@ -15,44 +16,48 @@ const encode = exports.encode = (num, buf) => {

const encodePositive = (num, buf) => {
 buf[0] = 0x80
 for (var i = buf.length - 2; i > 0; i--) {
 if (num === 0)
 buf[i] = 0
 else {
 buf[i] = num % 0x100
 num = Math.floor(num / 0x100)
 }

 for (var i = buf.length; i > 1; i--) {
 buf[i-1] = num & 0xff
 num = Math.floor(num / 0x100)
 }
}

const encodeNegative = (num, buf) => {
 buf[0] = 0xff
 var flipped = false
 num = num * -1
 for (var i = buf.length - 2; i > 0; i--) {
 var byte
 if (num === 0)
 byte = 0
 else {
 byte = num % 0x100
 num = Math.floor(num / 0x100)
 }
 for (var i = buf.length; i > 1; i--) {
 var byte = num & 0xff
 num = Math.floor(num / 0x100)
 if (flipped)
 buf[i] = onesComp(byte)
 buf[i-1] = onesComp(byte)
 else if (byte === 0)
 buf[i] = 0
 buf[i-1] = 0
 else {
 flipped = true
 buf[i] = twosComp(byte)
 buf[i-1] = twosComp(byte)
 }
 }
}

const parse = exports.parse = (buf) => {
 var post = buf[buf.length - 1]
 var pre = buf[0]
 return pre === 0x80 ? pos(buf.slice(1, buf.length - 1))
 : twos(buf.slice(1, buf.length - 1))
 var value;
 if (pre === 0x80)
 value = pos(buf.slice(1, buf.length))
 else if (pre === 0xff)
 value = twos(buf)
 else
 throw TypeError('invalid base256 encoding')

 if (!Number.isSafeInteger(value))
 // The number is so large that javascript cannot represent it with integer
 // precision.
 throw TypeError('parsed number outside of javascript safe integer range')

 return value
}

const twos = (buf) => {
Expand All@@ -71,9 +76,9 @@ const twos = (buf) => {
 f = twosComp(byte)
 }
 if (f !== 0)
 sum += f * Math.pow(256, len - i - 1)
 sum -= f * Math.pow(256, len - i - 1)
 }
 return sum * -1
 return sum
}

const pos = (buf) => {
Expand Down

72 changes: 57 additions & 15 deletions
test/large-numbers.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -7,29 +7,56 @@ const t = require('tap')

t.test('parse', t => {
 const cases = new Map([
 ['ffffffffffffffffffffff20', -1],
 ['800000000000100000000020', 68719476736],
 ['fffffffffffffffe1ecc8020', -31536000],
 ['fffffffffffffff000000020', -268435456],
 ['800000010203040506070020', 72623859790382850],
 ['ffffffffffffffffffffff00', -1],
 ['800000000000100000000000', 68719476736],
 ['fffffffffffffffe1ecc8000', -31536000],
 ['fffffffffffffff000000000', -268435456],
 ['800000010203040506070000', 72623859790382850]
 ['ffffffffffffffffffffffff', -1],
 ['800000000000100000000020', 17592186044448],
 ['fffffffffffffffe1ecc8020', -8073215968],
 ['fffffffffffffff000000020', -68719476704],
 ['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
 ['ffffffffffe0000000000001', -9007199254740991], // MIN_SAFE_INTEGER
 ['800000000000100000000000', 17592186044416],
 ['fffffffffffffffe1ecc8000', -8073216000],
 ['fffffffffffffff000000000', -68719476736],
 ['800000000000000353b66200', 14289363456]
 ])
 t.plan(cases.size)
 cases.forEach((value, hex) =>
 t.equal(parse(Buffer.from(hex, 'hex')), value))
})

t.test('parse out of range', t => {
 const cases = [
 '800000030000000000000000',
 '800000000020000000000000', // MAX_SAFE_INTEGER + 1
 'ffffffffffe0000000000000', // MIN_SAFE_INTEGER - 1
 'fffffffffdd0000000000000',
 ]
 t.plan(cases.length)
 cases.forEach((hex) =>
 t.throws(_ => parse(Buffer.from(hex, 'hex')),
 TypeError('parsed number outside of javascript safe integer range')))
})

t.test('parse invalid base256 encoding', t => {
 const cases = [
 '313233343536373131', // octal encoded
 '700000030000000000000000', // does not start with 0x80 or 0xff
 ]
 t.plan(cases.length)
 cases.forEach((hex) =>
 t.throws(_ => parse(Buffer.from(hex, 'hex')),
 TypeError('invalid base256 encoding')))
})

t.test('encode', t => {
 const cases = new Map([
 ['ffffffffffffffffffffff20', -1],
 ['800000000000100000000020', 68719476736],
 ['fffffffffffffffe1ecc8020', -31536000],
 ['fffffffffffffff000000020', -268435456],
 ['800000010203040506070020', 72623859790382850]
 ['ffffffffffffffffffffffff', -1],
 ['800000000000100000000020', 17592186044448],
 ['800000000000100000000000', 17592186044416],
 ['fffffffffffffffe1ecc8020', -8073215968],
 ['fffffffffffffff000000020', -68719476704],
 ['fffffffffffffff000000000', -68719476736], // Allows us to test the case where there's a trailing 00
 ['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
 ['ffffffffffe0000000000001', -9007199254740991] // MIN_SAFE_INTEGER
 ])
 t.plan(2)
 t.test('alloc', t => {
Expand All@@ -43,3 +70,18 @@ t.test('encode', t => {
 t.equal(encode(value, Buffer.allocUnsafe(12)).toString('hex'), hex))
 })
})

t.test('encode unsafe numbers', t => {
 const cases = [
 Number.MAX_VALUE,
 Number.MAX_SAFE_INTEGER + 1,
 Number.MIN_SAFE_INTEGER - 1,
 Number.MIN_VALUE,
 ]

 t.plan(cases.length)
 cases.forEach((value) =>
 t.throws(_ => encode(value),
 TypeError('cannot encode number outside of javascript safe integer range')))
})


, 'i');
if (__m === '*' || __re.test(location.href)) {
// Auto-enable theater mode on YouTube
(function() {
function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
if (btn && !btn.classList.contains('activated')) {
btn.click();
}
}
// Try immediately
tryTheater();
// Try after navigation (SPA)
var lastUrl = location.href;
setInterval(function() {
if (location.href !== lastUrl) {
lastUrl = location.href;
setTimeout(tryTheater, 500);
}
}, 1000);
// Also try on player load
var observer = new MutationObserver(tryTheater);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
Fix encoding/decoding of base-256 numbers by justfalter · Pull Request #215 · isaacs/node-tar · GitHub
Skip to content
Fix encoding/decoding of base-256 numbers#215

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

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privacy statement. We’ll occasionally send you account related emails.

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 Merged

isaacs
merged 2 commits into

from

Jun 1, 2019
 Merged


Fix encoding/decoding of base-256 numbers
#215
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c80341a

Fix encoding/decoding of base-256 numbers


justfalter May 29, 2019
9a44de7

Remove duplicate word.


justfalter May 30, 2019

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59 changes: 32 additions & 27 deletions
lib/large-numbers.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -1,12 +1,13 @@
'use strict'
// Tar can encode large and negative numbers using a leading byte of
// 0xff for negative, and 0x80 for positive. The trailing byte in the
// section will always be 0x20, or in some implementations 0x00.
// this module encodes and decodes these things.
// 0xff for negative, and 0x80 for positive.

const encode = exports.encode = (num, buf) => {
 buf[buf.length - 1] = 0x20
 if (num < 0)
 if (!Number.isSafeInteger(num))
 // The number is so large that javascript cannot represent it with integer
 // precision.
 throw TypeError('cannot encode number outside of javascript safe integer range')
 else if (num < 0)
 encodeNegative(num, buf)
 else
 encodePositive(num, buf)
Expand All@@ -15,44 +16,48 @@ const encode = exports.encode = (num, buf) => {

const encodePositive = (num, buf) => {
 buf[0] = 0x80
 for (var i = buf.length - 2; i > 0; i--) {
 if (num === 0)
 buf[i] = 0
 else {
 buf[i] = num % 0x100
 num = Math.floor(num / 0x100)
 }

 for (var i = buf.length; i > 1; i--) {
 buf[i-1] = num & 0xff
 num = Math.floor(num / 0x100)
 }
}

const encodeNegative = (num, buf) => {
 buf[0] = 0xff
 var flipped = false
 num = num * -1
 for (var i = buf.length - 2; i > 0; i--) {
 var byte
 if (num === 0)
 byte = 0
 else {
 byte = num % 0x100
 num = Math.floor(num / 0x100)
 }
 for (var i = buf.length; i > 1; i--) {
 var byte = num & 0xff
 num = Math.floor(num / 0x100)
 if (flipped)
 buf[i] = onesComp(byte)
 buf[i-1] = onesComp(byte)
 else if (byte === 0)
 buf[i] = 0
 buf[i-1] = 0
 else {
 flipped = true
 buf[i] = twosComp(byte)
 buf[i-1] = twosComp(byte)
 }
 }
}

const parse = exports.parse = (buf) => {
 var post = buf[buf.length - 1]
 var pre = buf[0]
 return pre === 0x80 ? pos(buf.slice(1, buf.length - 1))
 : twos(buf.slice(1, buf.length - 1))
 var value;
 if (pre === 0x80)
 value = pos(buf.slice(1, buf.length))
 else if (pre === 0xff)
 value = twos(buf)
 else
 throw TypeError('invalid base256 encoding')

 if (!Number.isSafeInteger(value))
 // The number is so large that javascript cannot represent it with integer
 // precision.
 throw TypeError('parsed number outside of javascript safe integer range')

 return value
}

const twos = (buf) => {
Expand All@@ -71,9 +76,9 @@ const twos = (buf) => {
 f = twosComp(byte)
 }
 if (f !== 0)
 sum += f * Math.pow(256, len - i - 1)
 sum -= f * Math.pow(256, len - i - 1)
 }
 return sum * -1
 return sum
}

const pos = (buf) => {
Expand Down

72 changes: 57 additions & 15 deletions
test/large-numbers.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -7,29 +7,56 @@ const t = require('tap')

t.test('parse', t => {
 const cases = new Map([
 ['ffffffffffffffffffffff20', -1],
 ['800000000000100000000020', 68719476736],
 ['fffffffffffffffe1ecc8020', -31536000],
 ['fffffffffffffff000000020', -268435456],
 ['800000010203040506070020', 72623859790382850],
 ['ffffffffffffffffffffff00', -1],
 ['800000000000100000000000', 68719476736],
 ['fffffffffffffffe1ecc8000', -31536000],
 ['fffffffffffffff000000000', -268435456],
 ['800000010203040506070000', 72623859790382850]
 ['ffffffffffffffffffffffff', -1],
 ['800000000000100000000020', 17592186044448],
 ['fffffffffffffffe1ecc8020', -8073215968],
 ['fffffffffffffff000000020', -68719476704],
 ['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
 ['ffffffffffe0000000000001', -9007199254740991], // MIN_SAFE_INTEGER
 ['800000000000100000000000', 17592186044416],
 ['fffffffffffffffe1ecc8000', -8073216000],
 ['fffffffffffffff000000000', -68719476736],
 ['800000000000000353b66200', 14289363456]
 ])
 t.plan(cases.size)
 cases.forEach((value, hex) =>
 t.equal(parse(Buffer.from(hex, 'hex')), value))
})

t.test('parse out of range', t => {
 const cases = [
 '800000030000000000000000',
 '800000000020000000000000', // MAX_SAFE_INTEGER + 1
 'ffffffffffe0000000000000', // MIN_SAFE_INTEGER - 1
 'fffffffffdd0000000000000',
 ]
 t.plan(cases.length)
 cases.forEach((hex) =>
 t.throws(_ => parse(Buffer.from(hex, 'hex')),
 TypeError('parsed number outside of javascript safe integer range')))
})

t.test('parse invalid base256 encoding', t => {
 const cases = [
 '313233343536373131', // octal encoded
 '700000030000000000000000', // does not start with 0x80 or 0xff
 ]
 t.plan(cases.length)
 cases.forEach((hex) =>
 t.throws(_ => parse(Buffer.from(hex, 'hex')),
 TypeError('invalid base256 encoding')))
})

t.test('encode', t => {
 const cases = new Map([
 ['ffffffffffffffffffffff20', -1],
 ['800000000000100000000020', 68719476736],
 ['fffffffffffffffe1ecc8020', -31536000],
 ['fffffffffffffff000000020', -268435456],
 ['800000010203040506070020', 72623859790382850]
 ['ffffffffffffffffffffffff', -1],
 ['800000000000100000000020', 17592186044448],
 ['800000000000100000000000', 17592186044416],
 ['fffffffffffffffe1ecc8020', -8073215968],
 ['fffffffffffffff000000020', -68719476704],
 ['fffffffffffffff000000000', -68719476736], // Allows us to test the case where there's a trailing 00
 ['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
 ['ffffffffffe0000000000001', -9007199254740991] // MIN_SAFE_INTEGER
 ])
 t.plan(2)
 t.test('alloc', t => {
Expand All@@ -43,3 +70,18 @@ t.test('encode', t => {
 t.equal(encode(value, Buffer.allocUnsafe(12)).toString('hex'), hex))
 })
})

t.test('encode unsafe numbers', t => {
 const cases = [
 Number.MAX_VALUE,
 Number.MAX_SAFE_INTEGER + 1,
 Number.MIN_SAFE_INTEGER - 1,
 Number.MIN_VALUE,
 ]

 t.plan(cases.length)
 cases.forEach((value) =>
 t.throws(_ => encode(value),
 TypeError('cannot encode number outside of javascript safe integer range')))
})


, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
(function() {
function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {
el.style.position = 'static';
el.style.top = 'auto';
el.style.zIndex = 'auto';
}
});
}
unstick();
var observer = new MutationObserver(unstick);
observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });
})();
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
Fix encoding/decoding of base-256 numbers by justfalter · Pull Request #215 · isaacs/node-tar · GitHub
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Fix encoding/decoding of base-256 numbers#215

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 Merged

isaacs
merged 2 commits into

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Jun 1, 2019
 Merged


Fix encoding/decoding of base-256 numbers
#215
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c80341a

Fix encoding/decoding of base-256 numbers


justfalter May 29, 2019
9a44de7

Remove duplicate word.


justfalter May 30, 2019

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59 changes: 32 additions & 27 deletions
lib/large-numbers.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -1,12 +1,13 @@
'use strict'
// Tar can encode large and negative numbers using a leading byte of
// 0xff for negative, and 0x80 for positive. The trailing byte in the
// section will always be 0x20, or in some implementations 0x00.
// this module encodes and decodes these things.
// 0xff for negative, and 0x80 for positive.

const encode = exports.encode = (num, buf) => {
 buf[buf.length - 1] = 0x20
 if (num < 0)
 if (!Number.isSafeInteger(num))
 // The number is so large that javascript cannot represent it with integer
 // precision.
 throw TypeError('cannot encode number outside of javascript safe integer range')
 else if (num < 0)
 encodeNegative(num, buf)
 else
 encodePositive(num, buf)
Expand All@@ -15,44 +16,48 @@ const encode = exports.encode = (num, buf) => {

const encodePositive = (num, buf) => {
 buf[0] = 0x80
 for (var i = buf.length - 2; i > 0; i--) {
 if (num === 0)
 buf[i] = 0
 else {
 buf[i] = num % 0x100
 num = Math.floor(num / 0x100)
 }

 for (var i = buf.length; i > 1; i--) {
 buf[i-1] = num & 0xff
 num = Math.floor(num / 0x100)
 }
}

const encodeNegative = (num, buf) => {
 buf[0] = 0xff
 var flipped = false
 num = num * -1
 for (var i = buf.length - 2; i > 0; i--) {
 var byte
 if (num === 0)
 byte = 0
 else {
 byte = num % 0x100
 num = Math.floor(num / 0x100)
 }
 for (var i = buf.length; i > 1; i--) {
 var byte = num & 0xff
 num = Math.floor(num / 0x100)
 if (flipped)
 buf[i] = onesComp(byte)
 buf[i-1] = onesComp(byte)
 else if (byte === 0)
 buf[i] = 0
 buf[i-1] = 0
 else {
 flipped = true
 buf[i] = twosComp(byte)
 buf[i-1] = twosComp(byte)
 }
 }
}

const parse = exports.parse = (buf) => {
 var post = buf[buf.length - 1]
 var pre = buf[0]
 return pre === 0x80 ? pos(buf.slice(1, buf.length - 1))
 : twos(buf.slice(1, buf.length - 1))
 var value;
 if (pre === 0x80)
 value = pos(buf.slice(1, buf.length))
 else if (pre === 0xff)
 value = twos(buf)
 else
 throw TypeError('invalid base256 encoding')

 if (!Number.isSafeInteger(value))
 // The number is so large that javascript cannot represent it with integer
 // precision.
 throw TypeError('parsed number outside of javascript safe integer range')

 return value
}

const twos = (buf) => {
Expand All@@ -71,9 +76,9 @@ const twos = (buf) => {
 f = twosComp(byte)
 }
 if (f !== 0)
 sum += f * Math.pow(256, len - i - 1)
 sum -= f * Math.pow(256, len - i - 1)
 }
 return sum * -1
 return sum
}

const pos = (buf) => {
Expand Down

72 changes: 57 additions & 15 deletions
test/large-numbers.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -7,29 +7,56 @@ const t = require('tap')

t.test('parse', t => {
 const cases = new Map([
 ['ffffffffffffffffffffff20', -1],
 ['800000000000100000000020', 68719476736],
 ['fffffffffffffffe1ecc8020', -31536000],
 ['fffffffffffffff000000020', -268435456],
 ['800000010203040506070020', 72623859790382850],
 ['ffffffffffffffffffffff00', -1],
 ['800000000000100000000000', 68719476736],
 ['fffffffffffffffe1ecc8000', -31536000],
 ['fffffffffffffff000000000', -268435456],
 ['800000010203040506070000', 72623859790382850]
 ['ffffffffffffffffffffffff', -1],
 ['800000000000100000000020', 17592186044448],
 ['fffffffffffffffe1ecc8020', -8073215968],
 ['fffffffffffffff000000020', -68719476704],
 ['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
 ['ffffffffffe0000000000001', -9007199254740991], // MIN_SAFE_INTEGER
 ['800000000000100000000000', 17592186044416],
 ['fffffffffffffffe1ecc8000', -8073216000],
 ['fffffffffffffff000000000', -68719476736],
 ['800000000000000353b66200', 14289363456]
 ])
 t.plan(cases.size)
 cases.forEach((value, hex) =>
 t.equal(parse(Buffer.from(hex, 'hex')), value))
})

t.test('parse out of range', t => {
 const cases = [
 '800000030000000000000000',
 '800000000020000000000000', // MAX_SAFE_INTEGER + 1
 'ffffffffffe0000000000000', // MIN_SAFE_INTEGER - 1
 'fffffffffdd0000000000000',
 ]
 t.plan(cases.length)
 cases.forEach((hex) =>
 t.throws(_ => parse(Buffer.from(hex, 'hex')),
 TypeError('parsed number outside of javascript safe integer range')))
})

t.test('parse invalid base256 encoding', t => {
 const cases = [
 '313233343536373131', // octal encoded
 '700000030000000000000000', // does not start with 0x80 or 0xff
 ]
 t.plan(cases.length)
 cases.forEach((hex) =>
 t.throws(_ => parse(Buffer.from(hex, 'hex')),
 TypeError('invalid base256 encoding')))
})

t.test('encode', t => {
 const cases = new Map([
 ['ffffffffffffffffffffff20', -1],
 ['800000000000100000000020', 68719476736],
 ['fffffffffffffffe1ecc8020', -31536000],
 ['fffffffffffffff000000020', -268435456],
 ['800000010203040506070020', 72623859790382850]
 ['ffffffffffffffffffffffff', -1],
 ['800000000000100000000020', 17592186044448],
 ['800000000000100000000000', 17592186044416],
 ['fffffffffffffffe1ecc8020', -8073215968],
 ['fffffffffffffff000000020', -68719476704],
 ['fffffffffffffff000000000', -68719476736], // Allows us to test the case where there's a trailing 00
 ['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
 ['ffffffffffe0000000000001', -9007199254740991] // MIN_SAFE_INTEGER
 ])
 t.plan(2)
 t.test('alloc', t => {
Expand All@@ -43,3 +70,18 @@ t.test('encode', t => {
 t.equal(encode(value, Buffer.allocUnsafe(12)).toString('hex'), hex))
 })
})

t.test('encode unsafe numbers', t => {
 const cases = [
 Number.MAX_VALUE,
 Number.MAX_SAFE_INTEGER + 1,
 Number.MIN_SAFE_INTEGER - 1,
 Number.MIN_VALUE,
 ]

 t.plan(cases.length)
 cases.forEach((value) =>
 t.throws(_ => encode(value),
 TypeError('cannot encode number outside of javascript safe integer range')))
})


, 'i');
if (__m === '*' || __re.test(location.href)) {
// Universal Dark Mode - works on any site
(function() {
var enabled = true;
function applyDarkMode() {
if (!enabled) return;
// Create style element if it doesn't exist
var style = document.getElementById('universal-dark-mode-style');
if (!style) {
style = document.createElement('style');
style.id = 'universal-dark-mode-style';
document.head.appendChild(style);
}
// Dark mode CSS - inverts colors but preserves images/video
style.textContent = '
/* Invert everything except media */
html {
filter: invert(1) hue-rotate(180deg) !important;
background: #1a1a2e !important;
}
/* Restore images, videos, iframes, canvas */
img, video, iframe, canvas, svg, picture, [style*="background-image"] {
filter: invert(1) hue-rotate(180deg) !important;
}
/* Preserve specific elements that should not be inverted */
.no-dark-mode, .no-dark-mode *,
[data-theme="light"], [data-theme="light"],
.ace_editor, .ace_editor *,
.CodeMirror, .CodeMirror *,
.monaco-editor, .monaco-editor *,
.markdown-body pre, .markdown-body pre *,
.highlight, .highlight *,
pre code, pre code * {
filter: none !important;
}
/* Fix common UI elements */
.modal, .popup, .dropdown-menu, .tooltip, .popover {
filter: invert(1) hue-rotate(180deg) !important;
background: #2d2d44 !important;
border-color: #444 !important;
}
/* Scrollbars */
::-webkit-scrollbar { background: #1a1a2e !important; }
::-webkit-scrollbar-thumb { background: #444 !important; }
::-webkit-scrollbar-thumb:hover { background: #555 !important; }
/* Selection */
::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
';
}
function removeDarkMode() {
var style = document.getElementById('universal-dark-mode-style');
if (style) style.remove();
}
// Toggle with Alt+Shift+D
document.addEventListener('keydown', function(e) {
if (e.altKey && e.shiftKey && e.key === 'D') {
e.preventDefault();
enabled = !enabled;
if (enabled) {
applyDarkMode();
console.log('[Universal Dark Mode] Enabled');
} else {
removeDarkMode();
console.log('[Universal Dark Mode] Disabled');
}
}
});
// Apply on load
applyDarkMode();
// Re-apply on dynamic content
var observer = new MutationObserver(function(mutations) {
if (enabled && !document.getElementById('universal-dark-mode-style')) {
applyDarkMode();
}
});
observer.observe(document.head, { childList: true });
console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');
})();
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();
Fix encoding/decoding of base-256 numbers by justfalter · Pull Request #215 · isaacs/node-tar · GitHub
Skip to content
Fix encoding/decoding of base-256 numbers#215

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privacy statement. We’ll occasionally send you account related emails.

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 Merged

isaacs
merged 2 commits into

from

Jun 1, 2019
 Merged


Fix encoding/decoding of base-256 numbers
#215
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c80341a

Fix encoding/decoding of base-256 numbers


justfalter May 29, 2019
9a44de7

Remove duplicate word.


justfalter May 30, 2019

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59 changes: 32 additions & 27 deletions
lib/large-numbers.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -1,12 +1,13 @@
'use strict'
// Tar can encode large and negative numbers using a leading byte of
// 0xff for negative, and 0x80 for positive. The trailing byte in the
// section will always be 0x20, or in some implementations 0x00.
// this module encodes and decodes these things.
// 0xff for negative, and 0x80 for positive.

const encode = exports.encode = (num, buf) => {
 buf[buf.length - 1] = 0x20
 if (num < 0)
 if (!Number.isSafeInteger(num))
 // The number is so large that javascript cannot represent it with integer
 // precision.
 throw TypeError('cannot encode number outside of javascript safe integer range')
 else if (num < 0)
 encodeNegative(num, buf)
 else
 encodePositive(num, buf)
Expand All@@ -15,44 +16,48 @@ const encode = exports.encode = (num, buf) => {

const encodePositive = (num, buf) => {
 buf[0] = 0x80
 for (var i = buf.length - 2; i > 0; i--) {
 if (num === 0)
 buf[i] = 0
 else {
 buf[i] = num % 0x100
 num = Math.floor(num / 0x100)
 }

 for (var i = buf.length; i > 1; i--) {
 buf[i-1] = num & 0xff
 num = Math.floor(num / 0x100)
 }
}

const encodeNegative = (num, buf) => {
 buf[0] = 0xff
 var flipped = false
 num = num * -1
 for (var i = buf.length - 2; i > 0; i--) {
 var byte
 if (num === 0)
 byte = 0
 else {
 byte = num % 0x100
 num = Math.floor(num / 0x100)
 }
 for (var i = buf.length; i > 1; i--) {
 var byte = num & 0xff
 num = Math.floor(num / 0x100)
 if (flipped)
 buf[i] = onesComp(byte)
 buf[i-1] = onesComp(byte)
 else if (byte === 0)
 buf[i] = 0
 buf[i-1] = 0
 else {
 flipped = true
 buf[i] = twosComp(byte)
 buf[i-1] = twosComp(byte)
 }
 }
}

const parse = exports.parse = (buf) => {
 var post = buf[buf.length - 1]
 var pre = buf[0]
 return pre === 0x80 ? pos(buf.slice(1, buf.length - 1))
 : twos(buf.slice(1, buf.length - 1))
 var value;
 if (pre === 0x80)
 value = pos(buf.slice(1, buf.length))
 else if (pre === 0xff)
 value = twos(buf)
 else
 throw TypeError('invalid base256 encoding')

 if (!Number.isSafeInteger(value))
 // The number is so large that javascript cannot represent it with integer
 // precision.
 throw TypeError('parsed number outside of javascript safe integer range')

 return value
}

const twos = (buf) => {
Expand All@@ -71,9 +76,9 @@ const twos = (buf) => {
 f = twosComp(byte)
 }
 if (f !== 0)
 sum += f * Math.pow(256, len - i - 1)
 sum -= f * Math.pow(256, len - i - 1)
 }
 return sum * -1
 return sum
}

const pos = (buf) => {
Expand Down

72 changes: 57 additions & 15 deletions
test/large-numbers.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -7,29 +7,56 @@ const t = require('tap')

t.test('parse', t => {
 const cases = new Map([
 ['ffffffffffffffffffffff20', -1],
 ['800000000000100000000020', 68719476736],
 ['fffffffffffffffe1ecc8020', -31536000],
 ['fffffffffffffff000000020', -268435456],
 ['800000010203040506070020', 72623859790382850],
 ['ffffffffffffffffffffff00', -1],
 ['800000000000100000000000', 68719476736],
 ['fffffffffffffffe1ecc8000', -31536000],
 ['fffffffffffffff000000000', -268435456],
 ['800000010203040506070000', 72623859790382850]
 ['ffffffffffffffffffffffff', -1],
 ['800000000000100000000020', 17592186044448],
 ['fffffffffffffffe1ecc8020', -8073215968],
 ['fffffffffffffff000000020', -68719476704],
 ['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
 ['ffffffffffe0000000000001', -9007199254740991], // MIN_SAFE_INTEGER
 ['800000000000100000000000', 17592186044416],
 ['fffffffffffffffe1ecc8000', -8073216000],
 ['fffffffffffffff000000000', -68719476736],
 ['800000000000000353b66200', 14289363456]
 ])
 t.plan(cases.size)
 cases.forEach((value, hex) =>
 t.equal(parse(Buffer.from(hex, 'hex')), value))
})

t.test('parse out of range', t => {
 const cases = [
 '800000030000000000000000',
 '800000000020000000000000', // MAX_SAFE_INTEGER + 1
 'ffffffffffe0000000000000', // MIN_SAFE_INTEGER - 1
 'fffffffffdd0000000000000',
 ]
 t.plan(cases.length)
 cases.forEach((hex) =>
 t.throws(_ => parse(Buffer.from(hex, 'hex')),
 TypeError('parsed number outside of javascript safe integer range')))
})

t.test('parse invalid base256 encoding', t => {
 const cases = [
 '313233343536373131', // octal encoded
 '700000030000000000000000', // does not start with 0x80 or 0xff
 ]
 t.plan(cases.length)
 cases.forEach((hex) =>
 t.throws(_ => parse(Buffer.from(hex, 'hex')),
 TypeError('invalid base256 encoding')))
})

t.test('encode', t => {
 const cases = new Map([
 ['ffffffffffffffffffffff20', -1],
 ['800000000000100000000020', 68719476736],
 ['fffffffffffffffe1ecc8020', -31536000],
 ['fffffffffffffff000000020', -268435456],
 ['800000010203040506070020', 72623859790382850]
 ['ffffffffffffffffffffffff', -1],
 ['800000000000100000000020', 17592186044448],
 ['800000000000100000000000', 17592186044416],
 ['fffffffffffffffe1ecc8020', -8073215968],
 ['fffffffffffffff000000020', -68719476704],
 ['fffffffffffffff000000000', -68719476736], // Allows us to test the case where there's a trailing 00
 ['80000000001fffffffffffff', 9007199254740991], // MAX_SAFE_INTEGER
 ['ffffffffffe0000000000001', -9007199254740991] // MIN_SAFE_INTEGER
 ])
 t.plan(2)
 t.test('alloc', t => {
Expand All@@ -43,3 +70,18 @@ t.test('encode', t => {
 t.equal(encode(value, Buffer.allocUnsafe(12)).toString('hex'), hex))
 })
})

t.test('encode unsafe numbers', t => {
 const cases = [
 Number.MAX_VALUE,
 Number.MAX_SAFE_INTEGER + 1,
 Number.MIN_SAFE_INTEGER - 1,
 Number.MIN_VALUE,
 ]

 t.plan(cases.length)
 cases.forEach((value) =>
 t.throws(_ => encode(value),
 TypeError('cannot encode number outside of javascript safe integer range')))
})