fast-check
Version:
Property based testing framework for JavaScript (like QuickCheck)
72 lines (71 loc) • 2.72 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.indexToMappedConstantMapperFor = indexToMappedConstantMapperFor;
exports.indexToMappedConstantUnmapperFor = indexToMappedConstantUnmapperFor;
const globals_1 = require("../../../utils/globals");
const safeObjectIs = Object.is;
function buildDichotomyEntries(entries) {
let currentFrom = 0;
const dichotomyEntries = [];
for (const entry of entries) {
const from = currentFrom;
currentFrom = from + entry.num;
const to = currentFrom - 1;
dichotomyEntries.push({ from, to, entry });
}
return dichotomyEntries;
}
function findDichotomyEntry(dichotomyEntries, choiceIndex) {
let min = 0;
let max = dichotomyEntries.length;
while (max - min > 1) {
const mid = ~~((min + max) / 2);
if (choiceIndex < dichotomyEntries[mid].from) {
max = mid;
}
else {
min = mid;
}
}
return dichotomyEntries[min];
}
function indexToMappedConstantMapperFor(entries) {
const dichotomyEntries = buildDichotomyEntries(entries);
return function indexToMappedConstantMapper(choiceIndex) {
const dichotomyEntry = findDichotomyEntry(dichotomyEntries, choiceIndex);
return dichotomyEntry.entry.build(choiceIndex - dichotomyEntry.from);
};
}
function buildReverseMapping(entries) {
const reverseMapping = { mapping: new globals_1.Map(), negativeZeroIndex: undefined };
let choiceIndex = 0;
for (let entryIdx = 0; entryIdx !== entries.length; ++entryIdx) {
const entry = entries[entryIdx];
for (let idxInEntry = 0; idxInEntry !== entry.num; ++idxInEntry) {
const value = entry.build(idxInEntry);
if (value === 0 && 1 / value === globals_1.Number.NEGATIVE_INFINITY) {
reverseMapping.negativeZeroIndex = choiceIndex;
}
else {
(0, globals_1.safeMapSet)(reverseMapping.mapping, value, choiceIndex);
}
++choiceIndex;
}
}
return reverseMapping;
}
function indexToMappedConstantUnmapperFor(entries) {
let reverseMapping = null;
return function indexToMappedConstantUnmapper(value) {
if (reverseMapping === null) {
reverseMapping = buildReverseMapping(entries);
}
const choiceIndex = safeObjectIs(value, -0)
? reverseMapping.negativeZeroIndex
: (0, globals_1.safeMapGet)(reverseMapping.mapping, value);
if (choiceIndex === undefined) {
throw new globals_1.Error('Unknown value encountered cannot be built using this mapToConstant');
}
return choiceIndex;
};
}