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Merge pull request #199 from geertweening/fix/amount_cap

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[FIX] cap IOU Amounts to their max and min value
This commit is contained in:
Geert Weening
2014-11-06 21:41:08 -08:00
parent a447f6b723 f05941fbc4
commit 0c22a9753e
2 changed files with 118 additions and 6 deletions
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48
src/js/ripple/amount.js
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@@ -54,7 +54,9 @@ var consts = {
// Maximum possible amount for non-XRP currencies using the maximum mantissa
// with maximum exponent. Corresponds to hex 0xEC6386F26FC0FFFF.
max_value: '9999999999999999e80'
max_value: '9999999999999999e80',
// Minimum possible amount for non-XRP currencies.
min_value: '-1000000000000000e-96'
};
// Add constants to Amount class
@@ -424,6 +426,33 @@ Amount.prototype.invert = function() {
return this.copy()._invert();
};
/**
* Canonicalize amount value
*
* Mirrors rippled's internal Amount representation
* From https://github.com/ripple/rippled/blob/develop/src/ripple/data/protocol/STAmount.h#L31-L40
*
* Internal form:
* 1: If amount is zero, then value is zero and offset is -100
* 2: Otherwise:
* legal offset range is -96 to +80 inclusive
* value range is 10^15 to (10^16 - 1) inclusive
* amount = value * [10 ^ offset]
*
* -------------------
*
* The amount can be epxresses as A x 10^B
* Where:
* - A must be an integer between 10^15 and (10^16)-1 inclusive
* - B must be between -96 and 80 inclusive
*
* This results
* - minumum: 10^15 x 10^-96 -> 10^-81 -> -1e-81
* - maximum: (10^16)-1 x 10^80 -> 9999999999999999e80
*
* @returns {Amount}
* @throws {Error} if offset exceeds legal ranges, meaning the amount value is bigger than supported
*/
Amount.prototype.canonicalize = function() {
if (!(this._value instanceof BigInteger)) {
// NaN.
@@ -447,9 +476,8 @@ Amount.prototype.canonicalize = function() {
}
}
// XXX Make sure not bigger than supported. Throw if so.
} else if (this.is_zero()) {
this._offset = -100;
this._offset = Amount.cMinOffset;
this._is_negative = false;
} else {
// Normalize mantissa to valid range.
@@ -465,6 +493,16 @@ Amount.prototype.canonicalize = function() {
}
}
// Make sure not bigger than supported. Throw if so.
if (this.is_negative() && this._offset < Amount.cMinOffset) {
throw new Error('Exceeding min value of ' + Amount.min_value);
}
// Make sure not smaller than supported. Throw if so.
if (!this.is_negative() && this._offset > Amount.cMaxOffset) {
throw new Error('Exceeding max value of ' + Amount.max_value);
}
return this;
};
@@ -539,9 +577,7 @@ Amount.prototype.equals = function(d, ignore_issuer) {
return this.equals(Amount.from_json(d));
}
var result = true;
result = !((!this.is_valid() || !d.is_valid())
var result = !((!this.is_valid() || !d.is_valid())
|| (this._is_native !== d._is_native)
|| (!this._value.equals(d._value) || this._offset !== d._offset)
|| (this._is_negative !== d._is_negative)