| 1 | /* |
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| 2 | cencoder.c - c source to a base64 encoding algorithm implementation |
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| 3 | |
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| 4 | This is part of the libb64 project, and has been placed in the public domain. |
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| 5 | For details, see http://sourceforge.net/projects/libb64 |
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| 6 | */ |
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| 7 | |
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| 8 | extern "C" |
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| 9 | { |
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| 10 | |
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| 11 | #include "cencode.h" |
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| 12 | |
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| 13 | const int CHARS_PER_LINE = 72; |
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| 14 | |
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| 15 | void base64_init_encodestate(base64_encodestate* state_in) |
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| 16 | { |
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| 17 | state_in->step = step_A; |
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| 18 | state_in->result = 0; |
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| 19 | state_in->stepcount = 0; |
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| 20 | } |
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| 21 | |
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| 22 | char base64_encode_value(char value_in) |
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| 23 | { |
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| 24 | static const char* encoding = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
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| 25 | if (value_in > 63) return '='; |
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| 26 | return encoding[(int)value_in]; |
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| 27 | } |
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| 28 | |
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| 29 | int base64_encode_block(const char* plaintext_in, int length_in, char* code_out, base64_encodestate* state_in) |
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| 30 | { |
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| 31 | const char* plainchar = plaintext_in; |
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| 32 | const char* const plaintextend = plaintext_in + length_in; |
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| 33 | char* codechar = code_out; |
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| 34 | char result; |
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| 35 | char fragment; |
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| 36 | |
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| 37 | result = state_in->result; |
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| 38 | |
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| 39 | switch (state_in->step) |
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| 40 | { |
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| 41 | while (1) |
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| 42 | { |
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| 43 | case step_A: |
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| 44 | if (plainchar == plaintextend) |
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| 45 | { |
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| 46 | state_in->result = result; |
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| 47 | state_in->step = step_A; |
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| 48 | return codechar - code_out; |
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| 49 | } |
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| 50 | fragment = *plainchar++; |
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| 51 | result = (fragment & 0x0fc) >> 2; |
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| 52 | *codechar++ = base64_encode_value(result); |
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| 53 | result = (fragment & 0x003) << 4; |
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| 54 | case step_B: |
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| 55 | if (plainchar == plaintextend) |
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| 56 | { |
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| 57 | state_in->result = result; |
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| 58 | state_in->step = step_B; |
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| 59 | return codechar - code_out; |
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| 60 | } |
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| 61 | fragment = *plainchar++; |
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| 62 | result |= (fragment & 0x0f0) >> 4; |
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| 63 | *codechar++ = base64_encode_value(result); |
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| 64 | result = (fragment & 0x00f) << 2; |
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| 65 | case step_C: |
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| 66 | if (plainchar == plaintextend) |
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| 67 | { |
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| 68 | state_in->result = result; |
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| 69 | state_in->step = step_C; |
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| 70 | return codechar - code_out; |
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| 71 | } |
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| 72 | fragment = *plainchar++; |
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| 73 | result |= (fragment & 0x0c0) >> 6; |
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| 74 | *codechar++ = base64_encode_value(result); |
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| 75 | result = (fragment & 0x03f) >> 0; |
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| 76 | *codechar++ = base64_encode_value(result); |
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| 77 | |
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| 78 | ++(state_in->stepcount); |
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| 79 | if (state_in->stepcount == CHARS_PER_LINE/4) |
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| 80 | { |
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| 81 | *codechar++ = '\n'; |
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| 82 | state_in->stepcount = 0; |
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| 83 | } |
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| 84 | } |
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| 85 | } |
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| 86 | /* control should not reach here */ |
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| 87 | return codechar - code_out; |
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| 88 | } |
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| 89 | |
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| 90 | int base64_encode_blockend(char* code_out, base64_encodestate* state_in) |
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| 91 | { |
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| 92 | char* codechar = code_out; |
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| 93 | |
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| 94 | switch (state_in->step) |
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| 95 | { |
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| 96 | case step_B: |
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| 97 | *codechar++ = base64_encode_value(state_in->result); |
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| 98 | *codechar++ = '='; |
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| 99 | *codechar++ = '='; |
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| 100 | break; |
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| 101 | case step_C: |
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| 102 | *codechar++ = base64_encode_value(state_in->result); |
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| 103 | *codechar++ = '='; |
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| 104 | break; |
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| 105 | case step_A: |
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| 106 | break; |
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| 107 | } |
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| 108 | *codechar++ = '\n'; |
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| 109 | |
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| 110 | return codechar - code_out; |
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| 111 | } |
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| 112 | |
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| 113 | } |
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