util: add util.fromDouble for convenience.

lib/node/config.js

@@ -416,7 +416,7 @@ Config.prototype.fixed = function fixed(key, exp, fallback) {
     return fallback;
 
   try {
-    return util.fromFixed(value.toString(10), exp || 0);
+    return util.fromDouble(value, exp || 0);
   } catch (e) {
     throw new Error(`${fmt(key)} must be a fixed number.`);
   }

lib/utils/util.js

@@ -863,6 +863,20 @@ util.toFixed = function toFixed(num, exp) {
   return `${sign}${hi}.${lo}`;
 };
 
+/**
+ * Parse a double float number and multiply by a
+ * power of ten (uses no floating point arithmetic).
+ * @param {Number} num
+ * @param {Number} exp - Number of decimal places.
+ * @returns {Number}
+ */
+
+util.fromDouble = function fromDouble(num, exp) {
+  assert(typeof num === 'number' && isFinite(num));
+  assert(Number.isSafeInteger(exp));
+  return util.fromFixed(num.toFixed(exp), exp);
+};
+
 /**
  * Parse a fixed number string and multiply by a
  * power of ten (uses no floating point arithmetic).

lib/utils/validator.js

@@ -273,7 +273,7 @@ Validator.prototype.fixed = function fixed(key, exp, fallback) {
     return fallback;
 
   try {
-    return util.fromFixed(value.toString(10), exp || 0);
+    return util.fromDouble(value, exp || 0);
   } catch (e) {
     throw new ValidationError(key, 'fixed number');
   }

test/script-test.js

@@ -8,6 +8,7 @@ const Script = require('../lib/script/script');
 const Witness = require('../lib/script/witness');
 const Stack = require('../lib/script/stack');
 const TX = require('../lib/primitives/tx');
+const util = require('../lib/utils/util');
 const encoding = require('../lib/utils/encoding');
 const opcodes = Script.opcodes;
 
@@ -39,9 +40,9 @@ function parseScriptTest(data) {
 
   comments += ` (${expected})`;
 
-  let amount = 0;
-  if (witArr.length !== 0)
-    amount = witArr.pop() * 1e8;
+  let value = 0;
+  if (witArr.length > 0)
+    value = util.fromDouble(witArr.pop(), 8);
 
   const witness = Witness.fromString(witArr);
   const input = Script.fromString(inpHex);
@@ -58,7 +59,7 @@ function parseScriptTest(data) {
     witness: witness,
     input: input,
     output: output,
-    amount: amount,
+    value: value,
     flags: flags,
     expected: expected,
     comments: comments
@@ -279,7 +280,7 @@ describe('Script', function() {
 
     const test = parseScriptTest(data);
     const {witness, input, output} = test;
-    const {amount, flags} = test;
+    const {value, flags} = test;
     const {expected, comments} = test;
 
     for (const noCache of [false, true]) {
@@ -300,7 +301,7 @@ describe('Script', function() {
           }],
           outputs: [{
             script: output,
-            value: amount
+            value: value
           }],
           locktime: 0
         });
@@ -319,7 +320,7 @@ describe('Script', function() {
           }],
           outputs: [{
             script: [],
-            value: amount
+            value: value
           }],
           locktime: 0
         });
@@ -331,7 +332,7 @@ describe('Script', function() {
 
         let err, res;
         try {
-          res = Script.verify(input, witness, output, tx, 0, amount, flags);
+          res = Script.verify(input, witness, output, tx, 0, value, flags);
         } catch (e) {
           err = e;
         }