False positive matches when pattern.length > 32 #136 #254 bugfix (#333)

* Initial tests (that fail) for #136

* Fix for maximum integer overflow in signed 32 bit number by applying ceiling. Also tests. Issue #136

src/bitap/bitap_search.js

@@ -48,7 +48,7 @@ module.exports = (text, pattern, patternAlphabet, { location = 0, distance = 100
   let finalScore = 1
   let binMax = patternLen + textLen
 
-  const mask = 1 << (patternLen - 1)
+  const mask = 1 << (patternLen <= 31 ? patternLen - 1 : 30)
 
   for (let i = 0; i < patternLen; i += 1) {
     // Scan for the best match; each iteration allows for one more error.
@@ -135,7 +135,7 @@ module.exports = (text, pattern, patternAlphabet, { location = 0, distance = 100
       distance
     })
 
-    // console.log('score', score, finalScore)
+    //console.log('score', score, finalScore)
 
     if (score > currentThreshold) {
       break
@@ -144,7 +144,7 @@ module.exports = (text, pattern, patternAlphabet, { location = 0, distance = 100
     lastBitArr = bitArr
   }
 
-  // console.log('FINAL SCORE', finalScore)
+  //console.log('FINAL SCORE', finalScore)
 
   // Count exact matches (those with a score of 0) to be "almost" exact
   return {

test/fuse.test.js

@@ -989,3 +989,46 @@ describe('Searching through a deeply nested object', () => {
     })
   })
 })
+
+describe('Searching using string large strings', () => {
+
+  const list = [{
+    text: 'pizza'
+  }, {
+    text: 'feast'
+  }, {
+    text: 'super+large+much+unique+36+very+wow+'
+  }]
+  const options = {
+    include: ['score', 'matches'],
+    shouldSort: true,
+    threshold: 0.5,
+    location: 0,
+    distance: 0,
+    maxPatternLength: 50,
+    minMatchCharLength: 4,
+    keys: [
+      'text'
+    ]
+  }
+  const fuse = new Fuse(list, options)
+
+  test('finds delicious pizza', () => {
+    expect(fuse.search('pizza')[0].text).toBe('pizza')
+  })
+  test('finds pizza when clumbsy', () => {
+    expect(fuse.search('pizze')[0].text).toBe('pizza')
+  })
+  test('finds no matches when string is exactly 31 characters', () => {
+    expect(fuse.search('this-string-is-exactly-31-chars')).toStrictEqual([])
+  })
+  test('finds no matches when string is exactly 32 characters', () => {
+    expect(fuse.search('this-string-is-exactly-32-chars-')).toStrictEqual([])
+  })
+  test('finds no matches when string is larger than 32 characters', () => {
+    expect(fuse.search('this-string-is-more-than-32-chars')).toStrictEqual([])
+  })
+  test('should find one match that is larger than 32 characters', () => {
+    expect(fuse.search('super+large+much+unique+36+very+wow+')[0].text).toBe('super+large+much+unique+36+very+wow+')
+  })
+})