This is xnu-8019. See this file in:
/* Copyright (c) (2010,2011,2012,2015,2016,2017,2018,2019) Apple Inc. All rights reserved.
 *
 * corecrypto is licensed under Apple Inc.’s Internal Use License Agreement (which
 * is contained in the License.txt file distributed with corecrypto) and only to 
 * people who accept that license. IMPORTANT:  Any license rights granted to you by 
 * Apple Inc. (if any) are limited to internal use within your organization only on 
 * devices and computers you own or control, for the sole purpose of verifying the 
 * security characteristics and correct functioning of the Apple Software.  You may 
 * not, directly or indirectly, redistribute the Apple Software or any portions thereof.
 */

#ifndef _CORECRYPTO_CCASN1_H_
#define _CORECRYPTO_CCASN1_H_

#include <corecrypto/cc.h>
#include <stdbool.h>
#include <string.h>

/* ASN.1 types for on the fly ASN.1 BER/DER encoding/decoding. Don't use
   these with the ccder interface, use the CCDER_ types instead. */
enum {
    CCASN1_EOL               = 0x00,
    CCASN1_BOOLEAN           = 0x01,
    CCASN1_INTEGER           = 0x02,
    CCASN1_BIT_STRING        = 0x03,
    CCASN1_OCTET_STRING      = 0x04,
    CCASN1_NULL              = 0x05,
    CCASN1_OBJECT_IDENTIFIER = 0x06,
    CCASN1_OBJECT_DESCRIPTOR = 0x07,
    /* External or instance-of 0x08 */
    CCASN1_REAL              = 0x09,
    CCASN1_ENUMERATED        = 0x0a,
    CCASN1_EMBEDDED_PDV      = 0x0b,
    CCASN1_UTF8_STRING       = 0x0c,
    /*                         0x0d */
    /*                         0x0e */
    /*                         0x0f */
    CCASN1_SEQUENCE          = 0x10,
    CCASN1_SET               = 0x11,
    CCASN1_NUMERIC_STRING    = 0x12,
    CCASN1_PRINTABLE_STRING  = 0x13,
    CCASN1_T61_STRING        = 0x14,
    CCASN1_VIDEOTEX_STRING   = 0x15,
    CCASN1_IA5_STRING        = 0x16,
    CCASN1_UTC_TIME          = 0x17,
    CCASN1_GENERALIZED_TIME  = 0x18,
    CCASN1_GRAPHIC_STRING    = 0x19,
    CCASN1_VISIBLE_STRING    = 0x1a,
    CCASN1_GENERAL_STRING    = 0x1b,
    CCASN1_UNIVERSAL_STRING  = 0x1c,
    /*                         0x1d */
    CCASN1_BMP_STRING        = 0x1e,
    CCASN1_HIGH_TAG_NUMBER   = 0x1f,
    CCASN1_TELETEX_STRING    = CCASN1_T61_STRING,

    CCASN1_TAG_MASK			 = 0xff,
    CCASN1_TAGNUM_MASK		 = 0x1f,

    CCASN1_METHOD_MASK		 = 0x20,
    CCASN1_PRIMITIVE		 = 0x00,
    CCASN1_CONSTRUCTED		 = 0x20,

    CCASN1_CLASS_MASK		 = 0xc0,
    CCASN1_UNIVERSAL		 = 0x00,
    CCASN1_APPLICATION		 = 0x40,
    CCASN1_CONTEXT_SPECIFIC	 = 0x80,
    CCASN1_PRIVATE			 = 0xc0,

    CCASN1_CONSTRUCTED_SET = CCASN1_SET | CCASN1_CONSTRUCTED,
    CCASN1_CONSTRUCTED_SEQUENCE = CCASN1_SEQUENCE | CCASN1_CONSTRUCTED,
};

typedef const unsigned char * ccoid_t;
#define CCOID(oid) (oid)

/* Returns the size of an oid including it's tag and length. */
CC_INLINE CC_PURE CC_NONNULL((1))
size_t ccoid_size(ccoid_t oid) {
    return 2 + CCOID(oid)[1];
}

CC_INLINE CC_PURE CC_NONNULL((1, 2))
bool ccoid_equal(ccoid_t oid1, ccoid_t oid2) {
    return  (ccoid_size(oid1) == ccoid_size(oid2)
            && memcmp(CCOID(oid1), CCOID(oid2), ccoid_size(oid1))== 0);
}

#endif /* _CORECRYPTO_CCASN1_H_ */