3.0 source code

OfficeWeb/vendor/touch/src/util/PositionMap.js

@@ -0,0 +1,127 @@
+/**
+ * @private
+ */
+Ext.define('Ext.util.PositionMap', {
+    config: {
+        minimumHeight: 50
+    },
+
+    constructor: function(config) {
+        this.map = [];
+        this.adjustments = {};
+        this.offset = 0;
+
+        this.initConfig(config);
+    },
+
+    populate: function(count, offset) {
+        var map = this.map = this.map || [],
+            minimumHeight = this.getMinimumHeight(),
+            i, previousIndex, ln;
+
+        // We add 1 item to the count so that we can get the height of the bottom item
+        count++;
+        map.length = count;
+
+        map[0] = 0;
+        for (i = offset + 1, ln = count - 1; i <= ln; i++) {
+            previousIndex = i - 1;
+            map[i] = map[previousIndex] + minimumHeight;
+        }
+
+        this.adjustments = {
+            indices: [],
+            heights: {}
+        };
+        this.offset = 0;
+        for (i = 1, ln = count - 1; i <= ln; i++) {
+            previousIndex = i - 1;
+            this.offset += map[i] - map[previousIndex] - minimumHeight;
+        }
+    },
+
+    setItemHeight: function(index, height) {
+        height = Math.max(height, this.getMinimumHeight());
+        if (height !== this.getItemHeight(index)) {
+            var adjustments = this.adjustments;
+            adjustments.indices.push(parseInt(index, 10));
+            adjustments.heights[index] = height;
+        }
+    },
+
+    update: function() {
+        var adjustments = this.adjustments,
+            indices = adjustments.indices,
+            heights = adjustments.heights,
+            map = this.map,
+            ln = indices.length,
+            minimumHeight = this.getMinimumHeight(),
+            difference = 0,
+            i, j, height, index, nextIndex, currentHeight;
+
+        if (!adjustments.indices.length) {
+            return false;
+        }
+
+        Ext.Array.sort(indices, function(a, b) {
+            return a - b;
+        });
+
+        for (i = 0; i < ln; i++) {
+            index = indices[i];
+            nextIndex = indices[i + 1] || map.length - 1;
+
+            currentHeight = (map[index + 1] !== undefined) ? (map[index + 1] - map[index] + difference) : minimumHeight;
+            height = heights[index];
+
+            difference += height - currentHeight;
+
+            for (j = index + 1; j <= nextIndex; j++) {
+                map[j] += difference;
+            }
+        }
+
+        this.offset += difference;
+        this.adjustments = {
+            indices: [],
+            heights: {}
+        };
+        return true;
+    },
+
+    getItemHeight: function(index) {
+        return this.map[index + 1] - this.map[index];
+    },
+
+    getTotalHeight: function() {
+        return ((this.map.length - 1) * this.getMinimumHeight()) + this.offset;
+    },
+
+    findIndex: function(pos) {
+        return this.map.length ? this.binarySearch(this.map, pos) : 0;
+    },
+
+    binarySearch: function(sorted, value) {
+        var start = 0,
+            end = sorted.length;
+
+        if (value < sorted[0]) {
+            return 0;
+        }
+        if (value > sorted[end - 1]) {
+            return end - 1;
+        }
+        while (start + 1 < end) {
+            var mid = (start + end) >> 1,
+                val = sorted[mid];
+            if (val == value) {
+                return mid;
+            } else if (val < value) {
+                start = mid;
+            } else {
+                end = mid;
+            }
+        }
+        return start;
+    }
+});