1 | /*
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2 | * Copyright(c) 2010, Norio Kobota, All rights reserved.
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3 | */
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4 |
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5 | #include <string.h>
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6 | #include <stdlib.h>
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7 |
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8 | #include "base64.h"
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9 |
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10 | static const char base64_encode_chars[] =
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11 | "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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12 | "abcdefghijklmnopqrstuvwxyz"
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13 | "0123456789+/";
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14 |
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15 | static const signed char base64_decode_chars[] = {
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16 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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17 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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18 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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19 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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20 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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21 | - 1, - 1, - 1, 62, - 1, - 1, - 1, 63,
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22 | 52, 53, 54, 55, 56, 57, 58, 59,
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23 | 60, 61, - 1, - 1, - 1, 0, - 1, - 1,
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24 | - 1, 0, 1, 2, 3, 4, 5, 6,
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25 | 7, 8, 9, 10, 11, 12, 13, 14,
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26 | 15, 16, 17, 18, 19, 20, 21, 22,
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27 | 23, 24, 25, - 1, - 1, - 1, - 1, - 1,
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28 | - 1, 26, 27, 28, 29, 30, 31, 32,
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29 | 33, 34, 35, 36, 37, 38, 39, 40,
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30 | 41, 42, 43, 44, 45, 46, 47, 48,
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31 | 49, 50, 51, - 1, - 1, - 1, - 1, - 1,
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32 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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33 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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34 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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35 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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36 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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37 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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38 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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39 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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40 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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41 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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42 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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43 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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44 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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45 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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46 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1,
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47 | - 1, - 1, - 1, - 1, - 1, - 1, - 1, - 1};
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48 |
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49 | int base64_encode(unsigned char *dst, size_t dstsiz, const unsigned char *src, size_t srcsiz) {
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50 | unsigned long x = 0UL;
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51 | int i = 0, l = 0;
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52 | unsigned char *pdst;
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53 |
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54 | pdst = dst;
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55 | for (; srcsiz > 0; src++, srcsiz--) {
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56 | x = x << 8 | *src;
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57 | for (l += 8; l >= 6; l -= 6) {
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58 | if (i >= dstsiz)
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59 | return -1;
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60 | pdst[i++] = base64_encode_chars[(x >> (l - 6)) & 0x3f];
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61 | }
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62 | }
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63 | if (l > 0) {
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64 | x <<= 6 - l;
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65 | if (i >= dstsiz)
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66 | return -1;
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67 | pdst[i++] = base64_encode_chars[x & 0x3f];
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68 | }
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69 | for (; i % 4;) {
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70 | if (i >= dstsiz)
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71 | return -1;
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72 | pdst[i++] = '=';
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73 | }
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74 | if (i >= dstsiz)
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75 | return -1;
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76 | pdst[i] = '\0';
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77 | return i;
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78 | }
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79 |
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80 | int base64_decode(unsigned char *dst, size_t dstsiz, const unsigned char *src) {
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81 | union {
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82 | unsigned long x;
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83 | char c[4];
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84 | } base64;
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85 | unsigned char *pdst;
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86 | int i, j = 0, k = 0;
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87 | size_t srcsiz = strlen((const char *)src);
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88 |
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89 | if ((srcsiz % 4) != 0) {
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90 | return -1;
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91 | }
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92 | base64.x = 0UL;
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93 | pdst = dst;
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94 | for (; srcsiz > 0; src+=4, srcsiz-=4) {
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95 | for (i = 0; i < 4; i++) {
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96 | if (base64_decode_chars[src[i]] == -1) {
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97 | return -1;
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98 | }
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99 | base64.x = base64.x << 6 | base64_decode_chars[src[i]];
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100 | j += (src[i] == '=');
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101 | }
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102 | for (i = 3; i > j; i--, k++) {
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103 | if (k >= dstsiz)
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104 | return -1;
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105 | *pdst++ = base64.c[i - 1];
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106 | }
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107 | }
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108 | if (k >= dstsiz)
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109 | return -1;
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110 | *pdst = '\0';
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111 | return 0;
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112 | }
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