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//
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// GZIP.m
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//
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// Version 1.1.1
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//
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// Created by Nick Lockwood on 03/06/2012.
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// Copyright (C) 2012 Charcoal Design
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//
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// Distributed under the permissive zlib License
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// Get the latest version from here:
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//
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// https://github.com/nicklockwood/GZIP
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//
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// This software is provided 'as-is', without any express or implied
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// warranty. In no event will the authors be held liable for any damages
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// arising from the use of this software.
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//
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// Permission is granted to anyone to use this software for any purpose,
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// including commercial applications, and to alter it and redistribute it
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// freely, subject to the following restrictions:
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//
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// 1. The origin of this software must not be misrepresented; you must not
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// claim that you wrote the original software. If you use this software
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// in a product, an acknowledgment in the product documentation would be
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// appreciated but is not required.
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//
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// 2. Altered source versions must be plainly marked as such, and must not be
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// misrepresented as being the original software.
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//
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// 3. This notice may not be removed or altered from any source distribution.
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//
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#import "NSData+YOHOGZIP.h"
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#import <zlib.h>
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#import <dlfcn.h>
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#pragma clang diagnostic ignored "-Wcast-qual"
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@implementation NSData (YOHOGZIP)
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static void *libzOpen()
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{
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static void *libz;
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static dispatch_once_t onceToken;
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dispatch_once(&onceToken, ^{
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libz = dlopen("/usr/lib/libz.dylib", RTLD_LAZY);
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});
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return libz;
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}
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- (NSData *)YHgzippedDataWithCompressionLevel:(float)level
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{
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if (self.length == 0 || [self YHisGzippedData])
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{
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return self;
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}
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void *libz = libzOpen();
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int (*deflateInit2_)(z_streamp, int, int, int, int, int, const char *, int) =
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(int (*)(z_streamp, int, int, int, int, int, const char *, int))dlsym(libz, "deflateInit2_");
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int (*deflate)(z_streamp, int) = (int (*)(z_streamp, int))dlsym(libz, "deflate");
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int (*deflateEnd)(z_streamp) = (int (*)(z_streamp))dlsym(libz, "deflateEnd");
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z_stream stream;
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stream.zalloc = Z_NULL;
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stream.zfree = Z_NULL;
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stream.opaque = Z_NULL;
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stream.avail_in = (uint)self.length;
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stream.next_in = (Bytef *)(void *)self.bytes;
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stream.total_out = 0;
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stream.avail_out = 0;
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static const NSUInteger ChunkSize = 16384;
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NSMutableData *output = nil;
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int compression = (level < 0.0f)? Z_DEFAULT_COMPRESSION: (int)(roundf(level * 9));
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if (deflateInit2(&stream, compression, Z_DEFLATED, 31, 8, Z_DEFAULT_STRATEGY) == Z_OK)
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{
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output = [NSMutableData dataWithLength:ChunkSize];
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while (stream.avail_out == 0)
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{
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if (stream.total_out >= output.length)
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{
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output.length += ChunkSize;
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}
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stream.next_out = (uint8_t *)output.mutableBytes + stream.total_out;
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stream.avail_out = (uInt)(output.length - stream.total_out);
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deflate(&stream, Z_FINISH);
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}
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deflateEnd(&stream);
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output.length = stream.total_out;
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}
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return output;
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}
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- (NSData *)YHgzippedData
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{
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return [self YHgzippedDataWithCompressionLevel:-1.0f];
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}
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- (NSData *)YHgunzippedData
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{
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if (self.length == 0 || ![self YHisGzippedData])
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{
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return self;
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}
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void *libz = libzOpen();
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int (*inflateInit2_)(z_streamp, int, const char *, int) =
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(int (*)(z_streamp, int, const char *, int))dlsym(libz, "inflateInit2_");
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int (*inflate)(z_streamp, int) = (int (*)(z_streamp, int))dlsym(libz, "inflate");
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int (*inflateEnd)(z_streamp) = (int (*)(z_streamp))dlsym(libz, "inflateEnd");
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z_stream stream;
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stream.zalloc = Z_NULL;
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stream.zfree = Z_NULL;
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stream.avail_in = (uint)self.length;
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stream.next_in = (Bytef *)self.bytes;
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stream.total_out = 0;
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stream.avail_out = 0;
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NSMutableData *output = nil;
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if (inflateInit2(&stream, 47) == Z_OK)
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{
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int status = Z_OK;
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output = [NSMutableData dataWithCapacity:self.length * 2];
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while (status == Z_OK)
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{
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if (stream.total_out >= output.length)
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{
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output.length += self.length / 2;
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}
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stream.next_out = (uint8_t *)output.mutableBytes + stream.total_out;
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stream.avail_out = (uInt)(output.length - stream.total_out);
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status = inflate (&stream, Z_SYNC_FLUSH);
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}
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if (inflateEnd(&stream) == Z_OK)
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{
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if (status == Z_STREAM_END)
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{
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output.length = stream.total_out;
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}
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}
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}
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return output;
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}
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- (BOOL)YHisGzippedData
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{
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const UInt8 *bytes = (const UInt8 *)self.bytes;
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return (self.length >= 2 && bytes[0] == 0x1f && bytes[1] == 0x8b);
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}
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@end |
...
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...
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