| [32] | 1 | #include "stdafx.h" |
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| 2 | |
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| 3 | #include "encode.h" |
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| 4 | |
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| [40] | 5 | const int CHARS_PER_LINE = 1950; |
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| [32] | 6 | |
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| 7 | void base64_init_encodestate(base64_encodestate* state_in) |
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| 8 | { |
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| 9 | state_in->step = step_A; |
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| 10 | state_in->result = 0; |
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| 11 | state_in->stepcount = 0; |
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| 12 | } |
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| 13 | |
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| 14 | char base64_encode_value(char value_in) |
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| 15 | { |
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| 16 | static const char* encoding = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
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| 17 | if (value_in > 63) return '='; |
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| 18 | return encoding[(int)value_in]; |
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| 19 | } |
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| 20 | |
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| 21 | int base64_encode_block(const char* plaintext_in, int length_in, char* code_out, base64_encodestate* state_in) |
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| 22 | { |
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| 23 | const char* plainchar = plaintext_in; |
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| 24 | const char* const plaintextend = plaintext_in + length_in; |
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| 25 | char* codechar = code_out; |
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| 26 | char result; |
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| 27 | char fragment; |
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| 28 | |
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| 29 | result = state_in->result; |
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| 30 | |
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| 31 | switch (state_in->step) |
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| 32 | { |
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| 33 | while (1) |
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| 34 | { |
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| 35 | case step_A: |
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| 36 | if (plainchar == plaintextend) |
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| 37 | { |
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| 38 | state_in->result = result; |
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| 39 | state_in->step = step_A; |
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| 40 | return codechar - code_out; |
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| 41 | } |
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| 42 | fragment = *plainchar++; |
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| 43 | result = (fragment & 0x0fc) >> 2; |
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| 44 | *codechar++ = base64_encode_value(result); |
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| 45 | result = (fragment & 0x003) << 4; |
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| 46 | case step_B: |
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| 47 | if (plainchar == plaintextend) |
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| 48 | { |
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| 49 | state_in->result = result; |
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| 50 | state_in->step = step_B; |
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| 51 | return codechar - code_out; |
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| 52 | } |
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| 53 | fragment = *plainchar++; |
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| 54 | result |= (fragment & 0x0f0) >> 4; |
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| 55 | *codechar++ = base64_encode_value(result); |
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| 56 | result = (fragment & 0x00f) << 2; |
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| 57 | case step_C: |
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| 58 | if (plainchar == plaintextend) |
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| 59 | { |
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| 60 | state_in->result = result; |
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| 61 | state_in->step = step_C; |
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| 62 | return codechar - code_out; |
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| 63 | } |
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| 64 | fragment = *plainchar++; |
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| 65 | result |= (fragment & 0x0c0) >> 6; |
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| 66 | *codechar++ = base64_encode_value(result); |
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| 67 | result = (fragment & 0x03f) >> 0; |
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| 68 | *codechar++ = base64_encode_value(result); |
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| 69 | |
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| 70 | ++(state_in->stepcount); |
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| 71 | if (state_in->stepcount == CHARS_PER_LINE/4) |
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| 72 | { |
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| 73 | *codechar++ = '\n'; |
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| 74 | state_in->stepcount = 0; |
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| 75 | } |
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| 76 | } |
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| 77 | } |
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| 78 | /* control should not reach here */ |
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| 79 | return codechar - code_out; |
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| 80 | } |
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| 81 | |
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| 82 | int base64_encode_blockend(char* code_out, base64_encodestate* state_in) |
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| 83 | { |
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| 84 | char* codechar = code_out; |
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| 85 | |
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| 86 | switch (state_in->step) |
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| 87 | { |
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| 88 | case step_B: |
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| 89 | *codechar++ = base64_encode_value(state_in->result); |
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| 90 | *codechar++ = '='; |
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| 91 | *codechar++ = '='; |
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| 92 | break; |
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| 93 | case step_C: |
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| 94 | *codechar++ = base64_encode_value(state_in->result); |
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| 95 | *codechar++ = '='; |
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| 96 | break; |
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| 97 | case step_A: |
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| 98 | break; |
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| 99 | } |
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| 100 | *codechar++ = '\n'; |
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| 101 | |
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| 102 | return codechar - code_out; |
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| 103 | } |
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| 104 | |
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