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// Copyright 2014-Present Zwopple Limited
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#import "PSWebSocketDeflater.h"
#import "PSWebSocketDeflater.h"
#import "PSWebSocketInternal.h"
#import <zlib.h>
@interface PSWebSocketDeflater() {
NSInteger _windowBits;
NSUInteger _memoryLevel;
uint8_t _chunkBuffer[16384];
z_stream _stream;
BOOL _ready;
NSMutableData *_buffer;
}
@end
@implementation PSWebSocketDeflater
#pragma mark - Initialization
- (instancetype)initWithWindowBits:(NSInteger)windowBits memoryLevel:(NSUInteger)memoryLevel {
if((self = [super init])) {
_windowBits = windowBits;
_memoryLevel = memoryLevel;
NSAssert(_windowBits >= -15 && _windowBits <= -1, @"windowBits must be between -15 and -1");
NSAssert(_memoryLevel >= 1 && _memoryLevel <= 9, @"memory level must be between 1 and 9");
bzero(&_stream, sizeof(_stream));
bzero(_chunkBuffer, sizeof(_chunkBuffer));
_ready = NO;
}
return self;
}
#pragma mark - Actions
- (BOOL)begin:(NSMutableData *)buffer error:(NSError *__autoreleasing *)outError {
NSParameterAssert(buffer);
if(![self ensureReady:outError]) {
return NO;
}
_buffer = buffer;
return YES;
}
- (BOOL)appendBytes:(const void *)bytes length:(NSUInteger)length error:(NSError *__autoreleasing *)outError {
NSParameterAssert(length);
// set input properties
_stream.avail_in = (uInt)length;
_stream.next_in = (Bytef *)bytes;
// inflate loop
do {
// set output properties
_stream.avail_out = (uInt)sizeof(_chunkBuffer);
_stream.next_out = (Bytef *)_chunkBuffer;
deflate(&_stream, Z_SYNC_FLUSH);
// determine number of bytes inflated
uInt gotBack = sizeof(_chunkBuffer) - _stream.avail_out;
if(gotBack > 0) {
[_buffer appendBytes:_chunkBuffer length:gotBack];
}
} while(_stream.avail_out == 0);
return YES;
}
- (BOOL)end:(NSError *__autoreleasing *)outError {
if(_buffer.length > 4) {
_buffer.length -= 4;
} else {
_buffer.length = 0;
}
return YES;
}
- (void)reset {
if(_ready) {
_buffer = nil;
deflateEnd(&_stream);
bzero(&_stream, sizeof(_stream));
bzero(_chunkBuffer, sizeof(_chunkBuffer));
_ready = NO;
}
}
#pragma mark - Private
- (BOOL)ensureReady:(NSError *__autoreleasing *)outError {
if(!_ready) {
if(deflateInit2(&_stream, Z_DEFAULT_COMPRESSION, Z_DEFLATED, _windowBits, _memoryLevel, Z_FIXED) != Z_OK) {
PSWebSocketSetOutError(outError, PSWebSocketStatusCodeProtocolError, @"Failed to initialize deflate stream");
return NO;
}
_ready = YES;
}
return YES;
}
#pragma mark - Dealloc
- (void)dealloc {
[self reset];
}
@end