Merge pull request #2 from awkward/feature-map

Added mapping helpers to NSArray

AWKHelpers.podspec

@@ -1,7 +1,7 @@
 
 Pod::Spec.new do |s|
   s.name             = "AWKHelpers"
-  s.version          = "0.5"
+  s.version          = "0.6"
   s.summary          = "A growing collection of UIKit and Foundation categories (helpers)"
   s.description      = <<-DESC
 A growing collection of UIKit and Foundation categories (helpers) we use at Awkward

Classes/AWKArrayHelper.h

@@ -8,6 +8,11 @@
 
 #import <Foundation/Foundation.h>
 
+typedef NS_OPTIONS(NSUInteger, AWKArrayMappingOptions) {
+    AWKArrayMapNilToNull = 1<<0,
+    AWKArrayMapNilToDeletion = 1<<1
+};
+
 @interface NSArray (AWKArrayHelper)
 
 /**
@@ -33,6 +38,16 @@
  */
 - (BOOL)hasObjectAtIndex:(NSUInteger)index;
 
+/**
+ Creates a new array with new objects mapped to the values of the receicer array. The new values should be defined by the parameter block.
+ 
+ @param mapBlock A block to return the destination values for the receiver array values. By default if you return nil, the new object will be copied from the receiver, unless you use a mapping option.
+ @param options Mapping options
+ 
+ @return A newly created array with modified values based on the receiver array.
+ */
+- (NSArray *)arrayByMappingObjectsWithBlock:(id (^)(id obj, NSUInteger idx))mapBlock options:(AWKArrayMappingOptions)options;
+
 @end
 
 @interface  NSMutableArray (AWKArrayHelper)
@@ -42,4 +57,13 @@
  */
 - (void)reverse;
 
+/**
+ Replaces all objects of the array with other objects, returned by the given mapping block.
+ 
+ @param mapBlock A block to return the new object to replace the old object in the array. By default, returning nil will result in an unchanged object, unless you use a mapping option.
+ @param options Mapping options
+ 
+ */
+- (void)replaceObjectsWithBlock:(id (^)(id obj, NSUInteger idx))mapBlock options:(AWKArrayMappingOptions)options;
+
 @end

Classes/AWKArrayHelper.m

@@ -42,6 +42,23 @@ - (BOOL)hasObjectAtIndex:(NSUInteger)index {
     return YES;
 }
 
+- (NSArray *)arrayByMappingObjectsWithBlock:(id (^)(id obj, NSUInteger idx))mapBlock options:(AWKArrayMappingOptions)options {
+    NSAssert(mapBlock!=nil, @"Map block should not be nil");
+    NSMutableArray *mappedArray = [[NSMutableArray alloc] initWithCapacity:self.count];
+    [self enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
+        id result = mapBlock(obj, idx);
+        if (result) {
+            [mappedArray addObject:result];
+        } else if (options&AWKArrayMapNilToNull) {
+            [mappedArray addObject:[NSNull null]];
+        } else if ((options&AWKArrayMapNilToDeletion) == 0) {
+            [mappedArray addObject:obj];
+        }
+    }];
+    NSArray *resultArray = [mappedArray copy];
+    return resultArray;
+}
+
 @end
 
 @implementation NSMutableArray (AWKArrayHelper)
@@ -61,4 +78,23 @@ - (void)reverse {
     }
 }
 
+- (void)replaceObjectsWithBlock:(id (^)(id obj, NSUInteger idx))mapBlock options:(AWKArrayMappingOptions)options{
+    NSAssert(mapBlock!=nil, @"Map block should not be nil");
+    NSMutableIndexSet *deletedIndices = [[NSMutableIndexSet alloc] init];
+    for (NSUInteger idx = 0; idx < self.count; idx++) {
+        id oldObject = self[idx];
+        id newObject = mapBlock(oldObject, idx);
+        if (newObject) {
+            [self replaceObjectAtIndex:idx withObject:newObject];
+        } else if (options&AWKArrayMapNilToNull) {
+            [self replaceObjectAtIndex:idx withObject:[NSNull null]];
+        } else if (options&AWKArrayMapNilToDeletion) {
+            [deletedIndices addIndex:idx];
+        }
+    }
+    if (deletedIndices.count > 0) {
+        [self removeObjectsAtIndexes:deletedIndices];
+    }
+}
+
 @end