NSData+GZIP from https://github.com/nicklockwood/GZIP minified for Segment

NSData+GZIP.h

//
//  GZIP.h
//
//  Version 1.1.1
//
//  Created by Nick Lockwood on 03/06/2012.
//  Copyright (C) 2012 Charcoal Design
//
//  Distributed under the permissive zlib License
//  Get the latest version from here:
//
//  https://github.com/nicklockwood/GZIP
//
//  This software is provided 'as-is', without any express or implied
//  warranty.  In no event will the authors be held liable for any damages
//  arising from the use of this software.
//
//  Permission is granted to anyone to use this software for any purpose,
//  including commercial applications, and to alter it and redistribute it
//  freely, subject to the following restrictions:
//
//  1. The origin of this software must not be misrepresented; you must not
//  claim that you wrote the original software. If you use this software
//  in a product, an acknowledgment in the product documentation would be
//  appreciated but is not required.
//
//  2. Altered source versions must be plainly marked as such, and must not be
//  misrepresented as being the original software.
//
//  3. This notice may not be removed or altered from any source distribution.
//


#import <Foundation/Foundation.h>


@interface NSData (GZIP)

- (nullable NSData *)gzippedData;

@end

NSData+GZIP.m

//
//  GZIP.m
//
//  Version 1.1.1
//
//  Created by Nick Lockwood on 03/06/2012.
//  Copyright (C) 2012 Charcoal Design
//
//  Distributed under the permissive zlib License
//  Get the latest version from here:
//
//  https://github.com/nicklockwood/GZIP
//
//  This software is provided 'as-is', without any express or implied
//  warranty.  In no event will the authors be held liable for any damages
//  arising from the use of this software.
//
//  Permission is granted to anyone to use this software for any purpose,
//  including commercial applications, and to alter it and redistribute it
//  freely, subject to the following restrictions:
//
//  1. The origin of this software must not be misrepresented; you must not
//  claim that you wrote the original software. If you use this software
//  in a product, an acknowledgment in the product documentation would be
//  appreciated but is not required.
//
//  2. Altered source versions must be plainly marked as such, and must not be
//  misrepresented as being the original software.
//
//  3. This notice may not be removed or altered from any source distribution.
//


#import "NSData+GZIP.h"
#import <zlib.h>
#import <dlfcn.h>


#pragma clang diagnostic ignored "-Wcast-qual"


@implementation NSData (GZIP)

static void *libzOpen()
{
    static void *libz;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        libz = dlopen("/usr/lib/libz.dylib", RTLD_LAZY);
    });
    return libz;
}

- (NSData *)gzippedDataWithCompressionLevel:(float)level
{
    if (self.length == 0 || [self isGzippedData]) {
        return self;
    }

    void *libz = libzOpen();
    int (*deflateInit2_)(z_streamp, int, int, int, int, int, const char *, int) =
        (int (*)(z_streamp, int, int, int, int, int, const char *, int))dlsym(libz, "deflateInit2_");
    int (*deflate)(z_streamp, int) = (int (*)(z_streamp, int))dlsym(libz, "deflate");
    int (*deflateEnd)(z_streamp) = (int (*)(z_streamp))dlsym(libz, "deflateEnd");

    z_stream stream;
    stream.zalloc = Z_NULL;
    stream.zfree = Z_NULL;
    stream.opaque = Z_NULL;
    stream.avail_in = (uint)self.length;
    stream.next_in = (Bytef *)(void *)self.bytes;
    stream.total_out = 0;
    stream.avail_out = 0;

    static const NSUInteger ChunkSize = 16384;

    NSMutableData *output = nil;
    int compression = (level < 0.0f) ? Z_DEFAULT_COMPRESSION : (int)(roundf(level * 9));
    if (deflateInit2(&stream, compression, Z_DEFLATED, 31, 8, Z_DEFAULT_STRATEGY) == Z_OK) {
        output = [NSMutableData dataWithLength:ChunkSize];
        while (stream.avail_out == 0) {
            if (stream.total_out >= output.length) {
                output.length += ChunkSize;
            }
            stream.next_out = (uint8_t *)output.mutableBytes + stream.total_out;
            stream.avail_out = (uInt)(output.length - stream.total_out);
            deflate(&stream, Z_FINISH);
        }
        deflateEnd(&stream);
        output.length = stream.total_out;
    }

    return output;
}

- (NSData *)gzippedData
{
    return [self gzippedDataWithCompressionLevel:-1.0f];
}

- (BOOL)isGzippedData
{
    const UInt8 *bytes = (const UInt8 *)self.bytes;
    return (self.length >= 2 && bytes[0] == 0x1f && bytes[1] == 0x8b);
}

@end