change findlowerbound behavior

src/helpers/util.js

@@ -44,32 +44,31 @@ module.exports = {
   /*
     Binary Search:
     Assumes that @arg array is sorted increasingly
-    return smallest i such that changes[i] <= target does not hold,
-    or changes.length if all elements are < target.
-    It returns the index where target could be inserted to maintain the order of the array
+    return largest i such that array[i] <= target; return -1 if array[0] > target || array is empty
   */
   findLowerBound: function (target, array) {
-    return findLowerBoundInternal(target, array, 0, array.length)
+    var start = 0
+    var length = array.length
+    while (length > 0) {
+      var half = length >> 1
+      var middle = start + half
+      if (array[middle] <= target) {
+        length = length - 1 - half
+        start = middle + 1
+      } else {
+        length = half
+      }
+    }
+    return start - 1
   },
 
+  /*
+    Binary Search:
+    Assumes that @arg array is sorted increasingly
+    return largest array[i] such that array[i] <= target; return null if array[0] > target || array is empty
+  */
   findLowerBoundValue: function (target, array) {
     var index = this.findLowerBound(target, array)
-    return array[index]
-  }
-}
-
-function findLowerBoundInternal (target, array, lowerbound, length) {
-  while (length > 1) {
-    var half = length >> 1
-    var middle = lowerbound + half
-    if (array[middle] < target) {
-      length = length - (middle - lowerbound)
-      lowerbound = middle
-    } else if (array[middle] === target) {
-      return middle
-    } else {
-      length = half
-    }
+    return index >= 0 ? array[index] : null
   }
-  return lowerbound
 }

src/util/sourceMappingDecoder.js

@@ -18,6 +18,9 @@ function SourceMappingDecoder () {
 SourceMappingDecoder.prototype.atIndex = function (index, mapping) {
   var ret = {}
   var map = mapping.split(';')
+  if (index >= map.length) {
+    index = map.length - 1
+  }
   for (var k = index; k >= 0; k--) {
     var current = map[k]
     if (!current.length) {
@@ -84,7 +87,7 @@ SourceMappingDecoder.prototype.getLinebreakPositions = function (source) {
  *
  * @param {Object} sourceLocation - object containing attributes {source} and {length}
  * @param {Array} lineBreakPositions - array returned by the function 'getLinebreakPositions'
- * @@return {Object} returns an object {start: {line, column}, end: {line, column}} (line count start at 0)
+ * @return {Object} returns an object {start: {line, column}, end: {line, column}} (line/column count start at 0)
  */
 SourceMappingDecoder.prototype.convertOffsetToLineColumn = function (sourceLocation, lineBreakPositions) {
   if (sourceLocation.start >= 0 && sourceLocation.length >= 0) {
@@ -94,21 +97,19 @@ SourceMappingDecoder.prototype.convertOffsetToLineColumn = function (sourceLocat
     }
   } else {
     return {
-      start: -1,
-      end: -1
+      start: null,
+      end: null
     }
   }
 }
 
 function convertFromCharPosition (pos, lineBreakPositions) {
   var line = util.findLowerBound(pos, lineBreakPositions)
-
-  if (lineBreakPositions[line] < pos) {
+  if (lineBreakPositions[line] !== pos) {
     line = line + 1
   }
-
-  var column = lineBreakPositions[line - 1] ? (pos - lineBreakPositions[line - 1] - 1) : pos
-
+  var beginColumn = line === 0 ? 0 : (lineBreakPositions[line - 1] + 1)
+  var column = pos - beginColumn
   return {
     line: line,
     column: column

test/util.js

@@ -2,78 +2,117 @@
 var sourceMapping = require('./resources/sourceMapping')
 var index = require('../src/index')
 var tape = require('tape')
+var util = require('../src/helpers/util')
 
 tape('Util', function (t) {
+  t.test('lowerbound', function (st) {
+    st.plan(7)
+    var array = [2, 5, 8, 9, 45, 56, 78]
+    var lowerBound = util.findLowerBound(10, array)
+    st.equal(lowerBound, 3)
+
+    lowerBound = util.findLowerBound(3, array)
+    st.equal(lowerBound, 0)
+
+    lowerBound = util.findLowerBound(100, array)
+    st.equal(lowerBound, 6)
+
+    lowerBound = util.findLowerBound(1, array)
+    st.equal(lowerBound, -1)
+
+    lowerBound = util.findLowerBound(45, array)
+    st.equal(lowerBound, 4)
+
+    array = [2, 5, 8, 9, 9, 45, 56, 78]
+    lowerBound = util.findLowerBound(9, array)
+    st.equal(lowerBound, 4)
+
+    lowerBound = util.findLowerBound(9, [])
+    st.equal(lowerBound, -1)
+  })
+
   var testSourceMapping = {}
   t.test('sourceMappingDecoder', function (st) {
     st.plan(28)
     var sourceMappingDecoder = new index.util.SourceMappingDecoder()
     console.log('test decompressAll')
     var result = sourceMappingDecoder.decompressAll(sourceMapping.mapping)
-    st.ok(result[0].start === 0)
-    st.ok(result[0].length === 205)
-    st.ok(result[0].file === 4)
-    st.ok(result[0].jump === '-')
-
-    st.ok(result[21].start === 0)
-    st.ok(result[21].length === 205)
-    st.ok(result[21].file === 4)
-    st.ok(result[21].jump === '-')
+    st.equal(result[0].start, 0)
+    st.equal(result[0].length, 205)
+    st.equal(result[0].file, 4)
+    st.equal(result[0].jump, '-')
+
+    st.equal(result[21].start, 0)
+    st.equal(result[21].length, 205)
+    st.equal(result[21].file, 4)
+    st.equal(result[21].jump, '-')
     testSourceMapping[21] = result[21]
 
-    st.ok(result[22].start === 55)
-    st.ok(result[22].length === 74)
-    st.ok(result[22].file === 4)
-    st.ok(result[22].jump === '-')
+    st.equal(result[22].start, 55)
+    st.equal(result[22].length, 74)
+    st.equal(result[22].file, 4)
+    st.equal(result[22].jump, '-')
 
     var last = result.length - 1
-    st.ok(result[last].start === 142)
-    st.ok(result[last].length === 61)
-    st.ok(result[last].file === 4)
-    st.ok(result[last].jump === 'o')
+    st.equal(result[last].start, 142)
+    st.equal(result[last].length, 61)
+    st.equal(result[last].file, 4)
+    st.equal(result[last].jump, 'o')
     testSourceMapping['last'] = result[last]
 
     console.log('test decompress')
     result = sourceMappingDecoder.atIndex(22, sourceMapping.mapping)
     console.log(result)
-    st.ok(result.start === 55)
-    st.ok(result.length === 74)
-    st.ok(result.file === 4)
-    st.ok(result.jump === '-')
+    st.equal(result.start, 55)
+    st.equal(result.length, 74)
+    st.equal(result.file, 4)
+    st.equal(result.jump, '-')
     testSourceMapping[22] = result
 
     result = sourceMappingDecoder.atIndex(82, sourceMapping.mapping)
     console.log(result)
-    st.ok(result.start === 103)
-    st.ok(result.length === 2)
-    st.ok(result.file === 4)
-    st.ok(result.jump === '-')
+    st.equal(result.start, 103)
+    st.equal(result.length, 2)
+    st.equal(result.file, 4)
+    st.equal(result.jump, '-')
     testSourceMapping[82] = result
 
     result = sourceMappingDecoder.atIndex(85, sourceMapping.mapping)
     console.log(result)
-    st.ok(result.start === 99)
-    st.ok(result.length === 6)
-    st.ok(result.file === 4)
-    st.ok(result.jump === '-')
+    st.equal(result.start, 99)
+    st.equal(result.length, 6)
+    st.equal(result.file, 4)
+    st.equal(result.jump, '-')
     testSourceMapping[85] = result
   })
 
   t.test('sourceMappingLineColumnConverter', function (st) {
-    st.plan(10)
+    st.plan(14)
     var sourceMappingDecoder = new index.util.SourceMappingDecoder()
     var linesbreak = sourceMappingDecoder.getLinebreakPositions(sourceMapping.source)
-    st.ok(linesbreak[0] === 16)
-    st.ok(linesbreak[5] === 84)
+    st.equal(linesbreak[0], 16)
+    st.equal(linesbreak[5], 84)
     var result = sourceMappingDecoder.convertOffsetToLineColumn(testSourceMapping[21], linesbreak)
-    st.ok(result.start.line === 0)
-    st.ok(result.start.column === 0)
-    st.ok(result.end.line === 15)
-    st.ok(result.end.column === 1)
+    st.equal(result.start.line, 0)
+    st.equal(result.start.column, 0)
+    st.equal(result.end.line, 15)
+    st.equal(result.end.column, 1)
     result = sourceMappingDecoder.convertOffsetToLineColumn(testSourceMapping[82], linesbreak)
-    st.ok(result.start.line === 7)
-    st.ok(result.start.column === 12)
-    st.ok(result.end.line === 7)
-    st.ok(result.end.column === 14)
+    st.equal(result.start.line, 7)
+    st.equal(result.start.column, 12)
+    st.equal(result.end.line, 7)
+    st.equal(result.end.column, 14)
+
+    var res = { // point to \n
+      start: 103,
+      length: 4,
+      file: 4,
+      jump: '-'
+    }
+    result = sourceMappingDecoder.convertOffsetToLineColumn(res, linesbreak)
+    st.equal(result.start.line, 7)
+    st.equal(result.start.column, 12)
+    st.equal(result.end.line, 7)
+    st.equal(result.end.column, 16)
   })
 })