(Objective-C) Convert ASN.1 to/from Binary DER, XML, and Base64

Demonstrates how to convert ASN.1 from and to any of the following formats: binary DER, Base64, and XML.

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#import <CkoAsn.h>
#import <NSString.h>
#import <CkoXml.h>

CkoAsn *asn = [[CkoAsn alloc] init];

BOOL success;

// Begin with loading ASN.1 from a binary DER/BER format file.
success = [asn LoadBinaryFile: @"/Users/chilkat/testData/p7b/test.p7b"];
if (success != YES) {
    NSLog(@"%@",asn.LastErrorText);
    return;
}

// Convert ASN.1 to XML:
NSString *strXml = [asn AsnToXml];
if (asn.LastMethodSuccess != YES) {
    NSLog(@"%@",asn.LastErrorText);
    return;
}

// The XML returned by AsnToXml will be compact and not pretty-formatted.
// Use Chilkat XML to format the XML better:
CkoXml *xml = [[CkoXml alloc] init];
success = [xml LoadXml: strXml];
// Assuming success for this example..
// This is formatted better for human viewing:
NSLog(@"%@",[xml GetXml]);

// Now get the ASN.1 in base64 format.  Any encoding supported
// by Chilkat can be passed, such as "hex", "uu", "quoted-printable", "base32", "modbase64", etc.
NSString *strBase64 = [asn GetEncodedDer: @"base64"];

// Load the ASN.1 from XML:
CkoAsn *asn2 = [[CkoAsn alloc] init];
success = [asn2 LoadAsnXml: [xml GetXml]];
if (success != YES) {
    NSLog(@"%@",asn2.LastErrorText);
    return;
}

// Load the ASN.1 from an encoded string, such as base64:
CkoAsn *asn3 = [[CkoAsn alloc] init];
success = [asn3 LoadEncoded: strBase64 encoding: @"base64"];
if (success != YES) {
    NSLog(@"%@",asn3.LastErrorText);
    return;
}