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1 | //----------------------------------------------------------------------------- | |
2 | // Copyright (C) 2018 grauerfuchs | |
3 | // | |
4 | // This code is licensed to you under the terms of the GNU GPL, version 2 or, | |
5 | // at your option, any later version. See the LICENSE.txt file for the text of | |
6 | // the license. | |
7 | //----------------------------------------------------------------------------- | |
8 | // HID card format packing/unpacking support functions | |
9 | //----------------------------------------------------------------------------- | |
10 | ||
11 | #include <stdbool.h> | |
12 | #include <stdint.h> | |
13 | #include <stdio.h> | |
14 | #include <string.h> | |
15 | #include "hidcardformatutils.h" | |
16 | #include "ui.h" | |
17 | ||
18 | bool get_bit_by_position(/* in */hidproxmessage_t* data, /* in */uint8_t pos){ | |
19 | if (pos >= data->Length) return false; | |
20 | pos = (data->Length - pos) - 1; // invert ordering; Indexing goes from 0 to 1. Subtract 1 for weight of bit. | |
21 | bool result = false; | |
22 | if (pos > 95) | |
23 | result = false; | |
24 | else if (pos > 63) | |
25 | result = (data->top >> (pos - 64)) & 1; | |
26 | else if (pos > 31) | |
27 | result = (data->mid >> (pos - 32)) & 1; | |
28 | else | |
29 | result = (data->bot >> pos) & 1; | |
30 | return result; | |
31 | } | |
32 | bool set_bit_by_position(/* inout */hidproxmessage_t* data, /* in */bool value, /* in */uint8_t pos){ | |
33 | if (pos >= data->Length) return false; | |
34 | pos = (data->Length - pos) - 1; // invert ordering; Indexing goes from 0 to 1. Subtract 1 for weight of bit. | |
35 | if (pos > 95) { | |
36 | return false; | |
37 | } else if (pos > 63) { | |
38 | if (value) | |
39 | data->top |= (1 << (pos - 64)); | |
40 | else | |
41 | data->top &= ~(1 << (pos - 64)); | |
42 | return true; | |
43 | } else if (pos > 31) { | |
44 | if (value) | |
45 | data->mid |= (1 << (pos - 32)); | |
46 | else | |
47 | data->mid &= ~(1 << (pos - 32)); | |
48 | return true; | |
49 | } else { | |
50 | if (value) | |
51 | data->bot |= (1 << pos); | |
52 | else | |
53 | data->bot &= ~(1 << pos); | |
54 | return true; | |
55 | } | |
56 | } | |
57 | /** | |
58 | * Safeguard the data by doing a manual deep copy | |
59 | * | |
60 | * At the time of the initial writing, the struct does not contain pointers. That doesn't | |
61 | * mean it won't eventually contain one, however. To prevent memory leaks and erroneous | |
62 | * aliasing, perform the copy function manually instead. Hence, this function. | |
63 | * | |
64 | * If the definition of the hidproxmessage struct changes, this function must also | |
65 | * be updated to match. | |
66 | */ | |
67 | void proxmessage_datacopy(/*in*/hidproxmessage_t* src, /*out*/hidproxmessage_t* dest){ | |
68 | dest->bot = src->bot; | |
69 | dest->mid = src->mid; | |
70 | dest->top = src->top; | |
71 | dest->Length = src->Length; | |
72 | } | |
73 | /** | |
74 | * | |
75 | * Yes, this is horribly inefficient for linear data. | |
76 | * The current code is a temporary measure to have a working function in place | |
77 | * until all the bugs shaken from the block/chunk version of the code. | |
78 | * | |
79 | */ | |
80 | uint64_t get_linear_field(/* in */hidproxmessage_t* data, uint8_t firstBit, uint8_t length){ | |
81 | uint64_t result = 0; | |
82 | for (uint8_t i = 0; i < length; i++ ) { | |
83 | result = (result << 1) | get_bit_by_position(data, firstBit + i); | |
84 | } | |
85 | return result; | |
86 | } | |
87 | bool set_linear_field(/* inout */hidproxmessage_t* data, uint64_t value, uint8_t firstBit, uint8_t length){ | |
88 | hidproxmessage_t tmpdata; | |
89 | proxmessage_datacopy(data, &tmpdata); | |
90 | bool result = true; | |
91 | for (int i = 0; i < length; i++){ | |
92 | result &= set_bit_by_position(&tmpdata, (value >> ((length - i) - 1)) & 1, firstBit + i); | |
93 | } | |
94 | if (result) proxmessage_datacopy(&tmpdata, data); | |
95 | return result; | |
96 | } | |
97 | ||
98 | uint64_t get_nonlinear_field(/* in */hidproxmessage_t* data, uint8_t numBits, uint8_t* bits){ | |
99 | uint64_t result = 0; | |
100 | for (int i = 0; i < numBits; i++){ | |
101 | result = (result << 1) | (get_bit_by_position(data, *(bits+i)) & 1); | |
102 | } | |
103 | return result; | |
104 | } | |
105 | bool set_nonlinear_field(/* inout */hidproxmessage_t* data, uint64_t value, uint8_t numBits, uint8_t* bits){ | |
106 | hidproxmessage_t tmpdata; | |
107 | proxmessage_datacopy(data, &tmpdata); | |
108 | bool result = true; | |
109 | for (int i = 0; i < numBits; i++){ | |
110 | result &= set_bit_by_position(&tmpdata, (value >> ((numBits - i) - 1)) & 1, *(bits + i)); | |
111 | } | |
112 | if (result) proxmessage_datacopy(&tmpdata, data); | |
113 | return result; | |
114 | } | |
115 | ||
116 | uint8_t get_length_from_header(/* inout */hidproxmessage_t* data) { | |
117 | uint8_t len = 0; | |
118 | ||
119 | uint32_t hFmt; // for calculating card length | |
120 | if ((data->top & 0x000FFFFF) > 0) { // > 64 bits | |
121 | hFmt = data->top & 0x000FFFFF; | |
122 | len = 64; | |
123 | } else if ((data->mid & 0xFFFFFFC0) > 0) { // < 63-38 bits | |
124 | hFmt = data->mid & 0xFFFFFFC0; | |
125 | len = 32; | |
126 | } else if ((data->mid & 0x00000020) == 0) { // 37 bits | |
127 | hFmt = 0; | |
128 | len = 37; | |
129 | } else if ((data->mid & 0x0000001F) > 0){ // 36-32 bits | |
130 | hFmt = data->mid & 0x0000001F; | |
131 | len = 32; | |
132 | } else { // <32 bits | |
133 | hFmt = data->bot; | |
134 | len = 0; | |
135 | } | |
136 | ||
137 | while (hFmt > 1) { | |
138 | hFmt >>= 1; | |
139 | len++; | |
140 | } | |
141 | return len; | |
142 | } | |
143 | ||
144 | hidproxmessage_t initialize_proxmessage_object(uint32_t top, uint32_t mid, uint32_t bot){ | |
145 | struct hidproxmessage_s result; | |
146 | memset(&result, 0, sizeof(hidproxmessage_t)); | |
147 | result.top = top; | |
148 | result.mid = mid; | |
149 | result.bot = bot; | |
150 | result.Length = get_length_from_header(&result); | |
151 | return result; | |
152 | } | |
153 | bool add_HID_header(/* inout */hidproxmessage_t* data){ | |
154 | if (data->Length > 84 || data->Length == 0) return false; // Invalid value | |
155 | ||
156 | if (data->Length >= 64){ | |
157 | data->top |= 1 << (data->Length - 64); // leading 1: start bit | |
158 | data->top |= 0x09e00000; // Extended-length header | |
159 | } else if (data->Length > 37){ | |
160 | data->mid |= 1 << (data->Length - 32); // leading 1: start bit | |
161 | data->top |= 0x09e00000; // Extended-length header | |
162 | } else if (data->Length == 37){ | |
163 | // No header bits added to 37-bit cards | |
164 | } else if (data->Length >= 32){ | |
165 | data->mid |= 0x20; // Bit 37; standard header | |
166 | data->mid |= 1 << (data->Length - 32); // leading 1: start bit | |
167 | } else { | |
168 | data->mid |= 0x20; // Bit 37; standard header | |
169 | data->bot |= 1 << data->Length; // leading 1: start bit | |
170 | } | |
171 | return true; | |
172 | } |