1 files changed, 6 insertions, 65 deletions

diff --git a/packages/utils/src/abi_encoder/evm_data_types/number.ts b/packages/utils/src/abi_encoder/evm_data_types/number.ts
index 86acdce07..053a574e3 100644
--- a/packages/utils/src/abi_encoder/evm_data_types/number.ts
+++ b/packages/utils/src/abi_encoder/evm_data_types/number.ts
@@ -1,11 +1,11 @@
 import { DataItem } from 'ethereum-types';
-import * as ethUtil from 'ethereumjs-util';
 import * as _ from 'lodash';
 
 import { BigNumber } from '../../configured_bignumber';
 import { DataTypeFactory, PayloadDataType } from '../abstract_data_types';
 import { RawCalldata } from '../calldata';
 import * as Constants from '../utils/constants';
+import * as EncoderMath from '../utils/math';
 
 export abstract class Number extends PayloadDataType {
     private static readonly _SIZE_KNOWN_AT_COMPILE_TIME: boolean = true;
@@ -25,73 +25,14 @@ export abstract class Number extends PayloadDataType {
                 : (this._width = Number._DEFAULT_WIDTH);
     }
 
-    public encodeValue(value_: BigNumber | string | number): Buffer {
-        const value = new BigNumber(value_, 10);
-        if (value.greaterThan(this.getMaxValue())) {
-            throw new Error(`Tried to assign value of ${value}, which exceeds max value of ${this.getMaxValue()}`);
-        } else if (value.lessThan(this.getMinValue())) {
-            throw new Error(`Tried to assign value of ${value}, which exceeds min value of ${this.getMinValue()}`);
-        }
-
-        let valueBuf: Buffer;
-        if (value.greaterThanOrEqualTo(0)) {
-            valueBuf = ethUtil.setLengthLeft(
-                ethUtil.toBuffer(`0x${value.toString(Constants.HEX_BASE)}`),
-                Constants.EVM_WORD_WIDTH_IN_BYTES,
-            );
-        } else {
-            // BigNumber can't write a negative hex value, so we use twos-complement conversion to do it ourselves.
-            // Step 1/3: Convert value to positive binary string
-            const binBase = 2;
-            const valueBin = value.times(-1).toString(binBase);
-
-            // Step 2/3: Invert binary value
-            let invertedValueBin = '1'.repeat(Constants.EVM_WORD_WIDTH_IN_BITS - valueBin.length);
-            _.each(valueBin, (bit: string) => {
-                invertedValueBin += bit === '1' ? '0' : '1';
-            });
-            const invertedValue = new BigNumber(invertedValueBin, binBase);
-
-            // Step 3/3: Add 1 to inverted value
-            // The result is the two's-complement represent of the input value.
-            const negativeValue = invertedValue.plus(1);
-
-            // Convert the negated value to a hex string
-            valueBuf = ethUtil.setLengthLeft(
-                ethUtil.toBuffer(`0x${negativeValue.toString(Constants.HEX_BASE)}`),
-                Constants.EVM_WORD_WIDTH_IN_BYTES,
-            );
-        }
-
-        return valueBuf;
+    public encodeValue(value: BigNumber | string | number): Buffer {
+        const encodedValue = EncoderMath.safeEncodeNumericValue(value, this.getMinValue(), this.getMaxValue());
+        return encodedValue;
     }
 
     public decodeValue(calldata: RawCalldata): BigNumber {
-        const paddedValueBuf = calldata.popWord();
-        const paddedValueHex = ethUtil.bufferToHex(paddedValueBuf);
-        let value = new BigNumber(paddedValueHex, 16);
-        if (this.getMinValue().lessThan(0)) {
-            // Check if we're negative
-            const valueBin = value.toString(Constants.BIN_BASE);
-            if (valueBin.length === Constants.EVM_WORD_WIDTH_IN_BITS && valueBin[0].startsWith('1')) {
-                // Negative
-                // Step 1/3: Invert binary value
-                let invertedValueBin = '';
-                _.each(valueBin, (bit: string) => {
-                    invertedValueBin += bit === '1' ? '0' : '1';
-                });
-                const invertedValue = new BigNumber(invertedValueBin, Constants.BIN_BASE);
-
-                // Step 2/3: Add 1 to inverted value
-                // The result is the two's-complement represent of the input value.
-                const positiveValue = invertedValue.plus(1);
-
-                // Step 3/3: Invert positive value
-                const negativeValue = positiveValue.times(-1);
-                value = negativeValue;
-            }
-        }
-
+        const valueBuf = calldata.popWord();
+        const value = EncoderMath.safeDecodeNumericValue(valueBuf, this.getMinValue(), this.getMaxValue());
         return value;
     }