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buffer: fix usage of kMaxLength
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Starting in V8 v4.3 the maximum array index of a typed array is the same
as the largest Smi supported on a given architecture. To compensate for
these differences export kMaxLength from the buffer module with the
correct size for the given architecture.

PR-URL: #2003
Reviewed-By: Chris Dickinson <christopher.s.dickinson@gmail.com>
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trevnorris authored and rvagg committed Jul 30, 2015
1 parent aa1d981 commit 53e2b8f
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Showing 6 changed files with 21 additions and 7 deletions.
2 changes: 1 addition & 1 deletion lib/fs.js
Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@ const Readable = Stream.Readable;
const Writable = Stream.Writable;

const kMinPoolSpace = 128;
const kMaxLength = process.binding('smalloc').kMaxLength;
const kMaxLength = require('buffer').kMaxLength;

const O_APPEND = constants.O_APPEND || 0;
const O_CREAT = constants.O_CREAT || 0;
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1 change: 1 addition & 0 deletions lib/internal/buffer_new.js
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ const internalUtil = require('internal/util');
exports.Buffer = Buffer;
exports.SlowBuffer = SlowBuffer;
exports.INSPECT_MAX_BYTES = 50;
exports.kMaxLength = binding.kMaxLength;


Buffer.poolSize = 8 * 1024;
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1 change: 1 addition & 0 deletions lib/internal/buffer_old.js
Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@ const kMaxLength = smalloc.kMaxLength;
exports.Buffer = Buffer;
exports.SlowBuffer = SlowBuffer;
exports.INSPECT_MAX_BYTES = 50;
exports.kMaxLength = binding.kMaxLength;


Buffer.poolSize = 8 * 1024;
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2 changes: 1 addition & 1 deletion lib/zlib.js
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Expand Up @@ -5,7 +5,7 @@ const Transform = require('_stream_transform');
const binding = process.binding('zlib');
const util = require('util');
const assert = require('assert').ok;
const kMaxLength = process.binding('smalloc').kMaxLength;
const kMaxLength = require('buffer').kMaxLength;
const kRangeErrorMessage = 'Cannot create final Buffer. ' +
'It would be larger than 0x' + kMaxLength.toString(16) + ' bytes.';

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11 changes: 11 additions & 0 deletions src/node_buffer.cc
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Expand Up @@ -71,6 +71,7 @@ using v8::FunctionCallbackInfo;
using v8::FunctionTemplate;
using v8::Handle;
using v8::HandleScope;
using v8::Integer;
using v8::Isolate;
using v8::Local;
using v8::Maybe;
Expand Down Expand Up @@ -1188,6 +1189,16 @@ void Initialize(Handle<Object> target,
env->SetMethod(target, "writeDoubleLE", WriteDoubleLE);
env->SetMethod(target, "writeFloatBE", WriteFloatBE);
env->SetMethod(target, "writeFloatLE", WriteFloatLE);

uint32_t kMaxLength;
if (sizeof(int32_t) == sizeof(intptr_t) || using_old_buffer) {
kMaxLength = 0x3fffffff;
} else {
kMaxLength = 0x7fffffff;
}
target->Set(env->context(),
FIXED_ONE_BYTE_STRING(env->isolate(), "kMaxLength"),
Integer::NewFromUnsigned(env->isolate(), kMaxLength)).FromJust();
}


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11 changes: 6 additions & 5 deletions test/parallel/test-regress-GH-io-1811.js
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Expand Up @@ -2,12 +2,13 @@

const assert = require('assert');

// Change kMaxLength for zlib to trigger the error
// without having to allocate 1GB of buffers
const smalloc = process.binding('smalloc');
smalloc.kMaxLength = 128;
// Change kMaxLength for zlib to trigger the error without having to allocate
// large Buffers.
const buffer = require('buffer');
const oldkMaxLength = buffer.kMaxLength;
buffer.kMaxLength = 128;
const zlib = require('zlib');
smalloc.kMaxLength = 0x3fffffff;
buffer.kMaxLength = oldkMaxLength;

const encoded = new Buffer('H4sIAAAAAAAAA0tMHFgAAIw2K/GAAAAA', 'base64');

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