//
|
// RACArraySequence.m
|
// ReactiveCocoa
|
//
|
// Created by Justin Spahr-Summers on 2012-10-29.
|
// Copyright (c) 2012 GitHub. All rights reserved.
|
//
|
|
#import "RACArraySequence.h"
|
|
@interface RACArraySequence ()
|
|
// Redeclared from the superclass and marked deprecated to prevent using `array`
|
// where `backingArray` is intended.
|
@property (nonatomic, copy, readonly) NSArray *array __attribute__((deprecated));
|
|
// The array being sequenced.
|
@property (nonatomic, copy, readonly) NSArray *backingArray;
|
|
// The index in the array from which the sequence starts.
|
@property (nonatomic, assign, readonly) NSUInteger offset;
|
|
@end
|
|
@implementation RACArraySequence
|
|
#pragma mark Lifecycle
|
|
+ (instancetype)sequenceWithArray:(NSArray *)array offset:(NSUInteger)offset {
|
NSCParameterAssert(offset <= array.count);
|
|
if (offset == array.count) return self.empty;
|
|
RACArraySequence *seq = [[self alloc] init];
|
seq->_backingArray = [array copy];
|
seq->_offset = offset;
|
return seq;
|
}
|
|
#pragma mark RACSequence
|
|
- (id)head {
|
return self.backingArray[self.offset];
|
}
|
|
- (RACSequence *)tail {
|
RACSequence *sequence = [self.class sequenceWithArray:self.backingArray offset:self.offset + 1];
|
sequence.name = self.name;
|
return sequence;
|
}
|
|
#pragma mark NSFastEnumeration
|
|
- (NSUInteger)countByEnumeratingWithState:(NSFastEnumerationState *)state objects:(__unsafe_unretained id[])stackbuf count:(NSUInteger)len {
|
NSCParameterAssert(len > 0);
|
|
if (state->state >= self.backingArray.count) {
|
// Enumeration has completed.
|
return 0;
|
}
|
|
if (state->state == 0) {
|
state->state = self.offset;
|
|
// Since a sequence doesn't mutate, this just needs to be set to
|
// something non-NULL.
|
state->mutationsPtr = state->extra;
|
}
|
|
state->itemsPtr = stackbuf;
|
|
NSUInteger startIndex = state->state;
|
NSUInteger index = 0;
|
|
for (id value in self.backingArray) {
|
// Constructing an index set for -enumerateObjectsAtIndexes: can actually be
|
// slower than just skipping the items we don't care about.
|
if (index < startIndex) {
|
++index;
|
continue;
|
}
|
|
stackbuf[index - startIndex] = value;
|
|
++index;
|
if (index - startIndex >= len) break;
|
}
|
|
NSCAssert(index > startIndex, @"Final index (%lu) should be greater than start index (%lu)", (unsigned long)index, (unsigned long)startIndex);
|
|
state->state = index;
|
return index - startIndex;
|
}
|
|
#pragma clang diagnostic push
|
#pragma clang diagnostic ignored "-Wdeprecated-implementations"
|
- (NSArray *)array {
|
return [self.backingArray subarrayWithRange:NSMakeRange(self.offset, self.backingArray.count - self.offset)];
|
}
|
#pragma clang diagnostic pop
|
|
#pragma mark NSCoding
|
|
- (id)initWithCoder:(NSCoder *)coder {
|
self = [super initWithCoder:coder];
|
if (self == nil) return nil;
|
|
_backingArray = [coder decodeObjectForKey:@"array"];
|
_offset = 0;
|
|
return self;
|
}
|
|
- (void)encodeWithCoder:(NSCoder *)coder {
|
// Encoding is handled in RACSequence.
|
[super encodeWithCoder:coder];
|
}
|
|
#pragma mark NSObject
|
|
- (NSString *)description {
|
return [NSString stringWithFormat:@"<%@: %p>{ name = %@, array = %@ }", self.class, self, self.name, self.backingArray];
|
}
|
|
@end
|
