1 /* 2 * Copyright (C) 2013 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ASN1_DECODER_H_ 18 #define ASN1_DECODER_H_ 19 20 #include <stddef.h> 21 #include <stdint.h> 22 23 class asn1_context { 24 public: asn1_context(const uint8_t * buffer,size_t length)25 asn1_context(const uint8_t* buffer, size_t length) : p_(buffer), length_(length), app_type_(0) {} 26 int asn1_constructed_type() const; 27 asn1_context* asn1_constructed_get(); 28 bool asn1_constructed_skip_all(); 29 asn1_context* asn1_sequence_get(); 30 asn1_context* asn1_set_get(); 31 bool asn1_sequence_next(); 32 bool asn1_oid_get(const uint8_t** oid, size_t* length); 33 bool asn1_octet_string_get(const uint8_t** octet_string, size_t* length); 34 35 private: 36 static constexpr int kMaskConstructed = 0xE0; 37 static constexpr int kMaskTag = 0x7F; 38 static constexpr int kMaskAppType = 0x1F; 39 40 static constexpr int kTagOctetString = 0x04; 41 static constexpr int kTagOid = 0x06; 42 static constexpr int kTagSequence = 0x30; 43 static constexpr int kTagSet = 0x31; 44 static constexpr int kTagConstructed = 0xA0; 45 46 int peek_byte() const; 47 int get_byte(); 48 bool skip_bytes(size_t num_skip); 49 bool decode_length(size_t* out_len); 50 51 const uint8_t* p_; 52 size_t length_; 53 int app_type_; 54 }; 55 56 #endif /* ASN1_DECODER_H_ */ 57