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Changes parseLengthCodedNumber to parse big numbers #382

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Merged
merged 18 commits into from
Jan 31, 2013
Merged

Changes parseLengthCodedNumber to parse big numbers #382

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9e5df78
Use bignumber.js to process numbers over js precision range
dresende Jan 29, 2013
c623bea
Adds new dependency on bignumber.js
dresende Jan 29, 2013
d5d8a0f
Optimizes big number discovery, based on code from kai-koch
dresende Jan 29, 2013
d8569fe
Adding small information about insert id returning string for big num…
dresende Jan 29, 2013
586554c
Moves BigNumber to top of file, fixes bug for first number after ieee…
dresende Jan 29, 2013
680aa2e
Really fixes checking for big number
dresende Jan 30, 2013
c073bd8
Updates parser test
dresende Jan 30, 2013
221fa7f
Changes big_number to bigNumber
dresende Jan 30, 2013
f5da5d1
Add supportBigNumbers to ConnectionConfig (false by default)
dresende Jan 30, 2013
0b6fecb
Pass config from Protocol to Parser
dresende Jan 30, 2013
f7a7378
Change Parser to look for supportBigNumbers option before checking fo…
dresende Jan 30, 2013
f5f9048
Change Parser to have the previous behavior of throwing when value ov…
dresende Jan 30, 2013
89ddb43
Revert Parser test
dresende Jan 30, 2013
09796a0
Changes Readme to mention supportBigNumbers option
dresende Jan 30, 2013
a413c6a
Changes RowDataPacket to check for big number support option and don'…
dresende Jan 30, 2013
1ea39e6
Add one more paragraph about precision limit and supportBigNumbers op…
dresende Jan 30, 2013
6ec07eb
Makes a few changes provided by @kai-koch
dresende Jan 30, 2013
04f2ab5
More changes... :)
dresende Jan 30, 2013
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21 changes: 12 additions & 9 deletions lib/protocol/Parser.js
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Original file line number Diff line number Diff line change
Expand Up @@ -164,20 +164,23 @@ Parser.prototype.parseLengthCodedNumber = function() {
throw new Error('parseLengthCodedNumber: Unexpected first byte: ' + byte);
}

var value = 0;
var value = 0, bigint = false, BigNumber = null;
for (var bytesRead = 0; bytesRead < length; bytesRead++) {
var byte = this._buffer[this._offset++];
value += Math.pow(256, bytesRead) * byte;
}

if (value >= IEEE_754_BINARY_64_PRECISION) {
throw new Error(
'parseLengthCodedNumber: JS precision range exceeded, ' +
'number is >= 53 bit: "' + value + '"'
);
// overflow
if (BigNumber) {
value = value.plus((new BigNumber(256)).pow(bytesRead).times(byte));
} else if (bytesRead == 7 && byte == 1) {
BigNumber = require("bignumber.js");
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This will make blocking FS calls, even if the module has been cached before. If you want to lazy-load this, you'll need to have a top-level variable that you use as an in-module cache.

edit: never mind, I see you're doing that. ignore me

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No, @felixge you were right. That variable is within the Parser.prototype.parseLengthCodedNumber function and should probably be moved out to the module level, otherwise require will be called each time a length coded number is parsed that is too large.

value = new BigNumber(value);
value = value.plus((new BigNumber(256)).pow(bytesRead).times(byte));
} else {
value += Math.pow(256, bytesRead) * byte;
}
}

return value;
return (BigNumber ? value.toString() : value);
};

Parser.prototype.parseFiller = function(length) {
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3 changes: 2 additions & 1 deletion package.json
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,8 @@
"node": "*"
},
"dependencies": {
"require-all": "0.0.3"
"require-all": "0.0.3",
"bignumber.js": "1.0.1"
},
"devDependencies": {
"utest": "0.0.6",
Expand Down