//

//  MYOID.m

//  MYCrypto

//

//  Created by Jens Alfke on 5/28/09.

//  Copyright 2009 Jens Alfke. All rights reserved.

//

#import "MYOID.h"

@implementation MYOID

- (id) initWithComponents: (const UInt32*)components count: (unsigned)count

{

    self = [super init];

    if (self != nil) {

        _data = [[NSData alloc] initWithBytes: components length: count*sizeof(UInt32)];

    }

    return self;

}

- (id) initWithBEREncoding: (NSData*)encoding

{

    self = [super init];

    if (self != nil) {

        size_t len = encoding.length;

        const UInt8 *src = encoding.bytes;

        const UInt8 *end = src+len;

        NSMutableData *data = [NSMutableData dataWithLength: (len+1)*sizeof(UInt32)];

        UInt32* dst = data.mutableBytes;

        if (len >= 2) {

            *dst++ = *src / 40;

            *dst++ = *src % 40;

            src++; 

        }

        while (src < end) {

            UInt32 component = 0;

            UInt8 byte;

            do{

                if (src >= end) {

                    [self release];

                    return nil;

                }

                byte = *src++;

                component = (component << 7) | (byte & 0x7F);

            }while (byte & 0x80);

            *dst++ = component;

        }

        data.length = (UInt8*)dst - (UInt8*)data.mutableBytes;

        _data = [data copy];

    }

    return self;

}

+ (MYOID*) OIDWithEncoding: (NSData*)encoding {

    return [[[self alloc] initWithBEREncoding: encoding] autorelease];

}

- (id) copyWithZone: (NSZone*)zone {

    return [self retain];

}

- (void) dealloc

{

    [_data release];

    [super dealloc];

}

- (NSString*) description {

    NSMutableString *desc = [NSMutableString stringWithString: @"{"];

    const UInt32* components = self.components;

    unsigned count = self.componentCount;

    for (unsigned i=0; i<count; i++) {

        if (i>0)

            [desc appendString: @" "];

        [desc appendFormat: @"%u", components[i]];

    }

    [desc appendString: @"}"];

    return desc;

}

- (NSData*) componentData       {return _data;}

- (const UInt32*) components    {return (const UInt32*)_data.bytes;}

- (unsigned) componentCount     {return _data.length / sizeof(UInt32);}

- (NSUInteger)hash {

    return _data.hash;

}

- (BOOL)isEqual:(id)object {

    return [object isKindOfClass: [MYOID class]] && [_data isEqual: [object componentData]];

}

- (NSData*) DEREncoding {

    unsigned count = self.componentCount;

    UInt8 encoding[5*count]; // worst-case size

    const UInt32 *src=self.components, *end=src+count;

    UInt8 *dst = encoding;

    if (count >= 2 && src[0]<=3 && src[1]<40) {

        // Weird collapsing of 1st two components into one byte:

        *dst++ = src[0]*40 + src[1];

        src += 2;

    }

    while (src<end) {

        UInt32 component = *src++;

        // Write the component in 7-bit groups, most significant first:

        BOOL any = NO;

        for (int shift=28; shift>=0; shift -= 7) {

            UInt8 byte = (component >> shift) & 0x7F;

            if (byte || any) {

                if (any)

                    dst[-1] |= 0x80;

                *dst++ = byte;

                any = YES;

            }

        }

    }

    return [NSData dataWithBytes: encoding length: dst-encoding];

}

@end

#define $data(BYTES...)    ({const uint8_t bytes[] = {BYTES}; [NSData dataWithBytes: bytes length: sizeof(bytes)];})

#define $components(INTS...)    ({const UInt32 components[] = {INTS}; components;})

TestCase(OID) {

    CAssertEqual([[MYOID OIDWithEncoding: $data(0x2a,0x86,0x48,0x86,0xf7,0x0d,0x01,0x01,0x01)] description],

                 @"{1 2 840 113549 1 1 1}");

    CAssertEqual([[MYOID OIDWithEncoding: $data(0x55,0x04,0x04)] description],

                 @"{2 5 4 4}");

    CAssertEqual([[MYOID OIDWithEncoding: $data(0x2a,0x86,0x48,0x86,0xf7,0x0d,0x01,0x09,0x01)] description],

                 @"{1 2 840 113549 1 9 1}");

    CAssertEqual([[[MYOID alloc] initWithComponents: $components(1,2,840,113549,1,1,1) count: 7] description],

                 @"{1 2 840 113549 1 1 1}");

    CAssertEqual([[[MYOID alloc] initWithComponents: $components(1,2,840,113549,1,1,1) count: 7] DEREncoding],

                 $data(0x2a, 0x86, 0x48, 0x86,  0xf7, 0x0d, 0x01, 0x01,  0x01));

    CAssertEqual([[[MYOID alloc] initWithComponents: $components(2,5,4,4) count: 4] DEREncoding],

                 $data(0x55,0x04,0x04));

}