1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Copyright 2003, Glenn McGrath
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4 | * Copyright 2006, Rob Landley <rob@landley.net>
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5 | * Copyright 2010, Denys Vlasenko
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6 | *
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7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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8 | */
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9 |
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10 | #include "libbb.h"
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11 |
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12 | /* Conversion table. for base 64 */
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13 | const char bb_uuenc_tbl_base64[65 + 2] ALIGN1 = {
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14 | 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
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15 | 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
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16 | 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
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17 | 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
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18 | 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
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19 | 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
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20 | 'w', 'x', 'y', 'z', '0', '1', '2', '3',
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21 | '4', '5', '6', '7', '8', '9', '+', '/',
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22 | '=' /* termination character */,
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23 | '\n', '\0' /* needed for uudecode.c */
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24 | };
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25 |
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26 | const char bb_uuenc_tbl_std[65] ALIGN1 = {
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27 | '`', '!', '"', '#', '$', '%', '&', '\'',
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28 | '(', ')', '*', '+', ',', '-', '.', '/',
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29 | '0', '1', '2', '3', '4', '5', '6', '7',
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30 | '8', '9', ':', ';', '<', '=', '>', '?',
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31 | '@', 'A', 'B', 'C', 'D', 'E', 'F', 'G',
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32 | 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
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33 | 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
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34 | 'X', 'Y', 'Z', '[', '\\', ']', '^', '_',
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35 | '`' /* termination character */
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36 | };
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37 |
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38 | /*
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39 | * Encode bytes at S of length LENGTH to uuencode or base64 format and place it
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40 | * to STORE. STORE will be 0-terminated, and must point to a writable
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41 | * buffer of at least 1+BASE64_LENGTH(length) bytes.
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42 | * where BASE64_LENGTH(len) = (4 * ((LENGTH + 2) / 3))
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43 | */
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44 | void FAST_FUNC bb_uuencode(char *p, const void *src, int length, const char *tbl)
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45 | {
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46 | const unsigned char *s = src;
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47 |
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48 | /* Transform the 3x8 bits to 4x6 bits */
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49 | while (length > 0) {
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50 | unsigned s1, s2;
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51 |
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52 | /* Are s[1], s[2] valid or should be assumed 0? */
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53 | s1 = s2 = 0;
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54 | length -= 3; /* can be >=0, -1, -2 */
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55 | if (length >= -1) {
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56 | s1 = s[1];
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57 | if (length >= 0)
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58 | s2 = s[2];
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59 | }
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60 | *p++ = tbl[s[0] >> 2];
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61 | *p++ = tbl[((s[0] & 3) << 4) + (s1 >> 4)];
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62 | *p++ = tbl[((s1 & 0xf) << 2) + (s2 >> 6)];
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63 | *p++ = tbl[s2 & 0x3f];
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64 | s += 3;
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65 | }
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66 | /* Zero-terminate */
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67 | *p = '\0';
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68 | /* If length is -2 or -1, pad last char or two */
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69 | while (length) {
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70 | *--p = tbl[64];
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71 | length++;
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72 | }
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73 | }
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74 |
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75 | /*
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76 | * Decode base64 encoded stream.
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77 | * Can stop on EOF, specified char, or on uuencode-style "====" line:
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78 | * flags argument controls it.
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79 | */
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80 | void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags)
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81 | {
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82 | /* Note that EOF _can_ be passed as exit_char too */
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83 | #define exit_char ((int)(signed char)flags)
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84 | #define uu_style_end (flags & BASE64_FLAG_UU_STOP)
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85 |
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86 | int term_count = 0;
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87 |
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88 | while (1) {
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89 | unsigned char translated[4];
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90 | int count = 0;
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91 |
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92 | /* Process one group of 4 chars */
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93 | while (count < 4) {
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94 | char *table_ptr;
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95 | int ch;
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96 |
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97 | /* Get next _valid_ character.
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98 | * bb_uuenc_tbl_base64[] contains this string:
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99 | * 0 1 2 3 4 5 6
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100 | * 012345678901234567890123456789012345678901234567890123456789012345
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101 | * "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n"
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102 | */
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103 | do {
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104 | ch = fgetc(src_stream);
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105 | if (ch == exit_char && count == 0)
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106 | return;
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107 | if (ch == EOF)
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108 | bb_error_msg_and_die("truncated base64 input");
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109 | table_ptr = strchr(bb_uuenc_tbl_base64, ch);
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110 | //TODO: add BASE64_FLAG_foo to die on bad char?
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111 | //Note that then we may need to still allow '\r' (for mail processing)
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112 | } while (!table_ptr);
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113 |
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114 | /* Convert encoded character to decimal */
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115 | ch = table_ptr - bb_uuenc_tbl_base64;
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116 |
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117 | if (ch == 65 /* '\n' */) {
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118 | /* Terminating "====" line? */
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119 | if (uu_style_end && term_count == 4)
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120 | return; /* yes */
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121 | term_count = 0;
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122 | continue;
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123 | }
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124 | /* ch is 64 if char was '=', otherwise 0..63 */
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125 | translated[count] = ch & 63; /* 64 -> 0 */
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126 | if (ch == 64) {
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127 | term_count++;
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128 | break;
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129 | }
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130 | count++;
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131 | term_count = 0;
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132 | }
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133 |
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134 | /* Merge 6 bit chars to 8 bit.
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135 | * count can be < 4 when we decode the tail:
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136 | * "eQ==" -> "y", not "y NUL NUL"
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137 | */
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138 | if (count > 1)
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139 | fputc(translated[0] << 2 | translated[1] >> 4, dst_stream);
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140 | if (count > 2)
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141 | fputc(translated[1] << 4 | translated[2] >> 2, dst_stream);
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142 | if (count > 3)
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143 | fputc(translated[2] << 6 | translated[3], dst_stream);
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144 | } /* while (1) */
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145 | }
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