1 /*
2 * Copyright (C) 2017 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 #include <apdu/apdu.h>
18
19 #include <limits>
20
21 namespace android {
22
CommandApdu(const uint8_t cla,const uint8_t ins,const uint8_t p1,const uint8_t p2,const size_t lc,const size_t le)23 CommandApdu::CommandApdu(const uint8_t cla, const uint8_t ins, const uint8_t p1, const uint8_t p2,
24 const size_t lc, const size_t le) {
25 constexpr size_t headerSize = 4;
26 constexpr size_t shortLcMax = std::numeric_limits<uint8_t>::max();
27 constexpr size_t shortLeMax = std::numeric_limits<uint8_t>::max() + 1;
28 //constexpr size_t extendedLcMax = std::numeric_limits<uint16_t>::max();
29 constexpr size_t extendedLeMax = std::numeric_limits<uint16_t>::max() + 1;
30
31 const bool extended = lc > shortLcMax || le > shortLeMax;
32 const bool hasLc = lc > 0;
33 const bool hasLe = le > 0;
34 const size_t lcSize = hasLc ? (extended ? 3 : 1) : 0;
35 const size_t leSize = hasLe ? (extended ? (hasLc ? 2 : 3) : 1) : 0;
36 const size_t commandSize = headerSize + lcSize + lc + leSize;
37 mCommand.resize(commandSize, 0);
38
39 // All cases have the header
40 auto it = mCommand.begin();
41 *it++ = cla;
42 *it++ = ins;
43 *it++ = p1;
44 *it++ = p2;
45
46 // Cases 3 & 4 send data
47 if (hasLc) {
48 if (extended) {
49 *it++ = 0;
50 *it++ = 0xff & (lc >> 8);
51 }
52 *it++ = 0xff & lc;
53 mDataBegin = it;
54 it += lc;
55 mDataEnd = it;
56 } else {
57 mDataBegin = mDataEnd = mCommand.end();
58 }
59
60 // Cases 2 & 4 expect data back
61 if (hasLe) {
62 if (extended) {
63 if (!hasLc) {
64 *it++ = 0;
65 }
66 const bool isLeMax = le == extendedLeMax;
67 *it++ = (isLeMax ? 0 : 0xff & (le >> 8));
68 *it++ = (isLeMax ? 0 : 0xff & le);
69 } else {
70 *it++ = (le == shortLeMax ? 0 : 0xff & le);
71 }
72 }
73 }
74
75 } // namespace android
76