mirror of
https://github.com/0xFEEDC0DE64/arduino-esp32.git
synced 2025-10-31 14:11:42 +01:00
450df7e3f8
Implements: https://github.com/esp8266/Arduino/pull/2883 Fixes: https://github.com/espressif/arduino-esp32/issues/313 Fixes: https://github.com/espressif/arduino-esp32/issues/344
100 lines
3.6 KiB
C
Executable File
100 lines
3.6 KiB
C
Executable File
/*
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cdecoder.c - c source to a base64 decoding algorithm implementation
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This is part of the libb64 project, and has been placed in the public domain.
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For details, see http://sourceforge.net/projects/libb64
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*/
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#include "cdecode.h"
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#include <stdint.h>
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static int base64_decode_value_signed(int8_t value_in){
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static const int8_t decoding[] = {62,-1,-1,-1,63,52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-2,-1,-1,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,-1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51};
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static const int8_t decoding_size = sizeof(decoding);
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value_in -= 43;
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if (value_in < 0 || value_in > decoding_size) return -1;
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return decoding[(int)value_in];
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}
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void base64_init_decodestate(base64_decodestate* state_in){
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state_in->step = step_a;
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state_in->plainchar = 0;
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}
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static int base64_decode_block_signed(const int8_t* code_in, const int length_in, int8_t* plaintext_out, base64_decodestate* state_in){
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const int8_t* codechar = code_in;
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int8_t* plainchar = plaintext_out;
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int8_t fragment;
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*plainchar = state_in->plainchar;
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switch (state_in->step){
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while (1){
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case step_a:
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do {
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if (codechar == code_in+length_in){
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state_in->step = step_a;
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state_in->plainchar = *plainchar;
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return plainchar - plaintext_out;
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}
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fragment = (int8_t)base64_decode_value_signed(*codechar++);
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} while (fragment < 0);
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*plainchar = (fragment & 0x03f) << 2;
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case step_b:
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do {
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if (codechar == code_in+length_in){
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state_in->step = step_b;
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state_in->plainchar = *plainchar;
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return plainchar - plaintext_out;
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}
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fragment = (int8_t)base64_decode_value_signed(*codechar++);
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} while (fragment < 0);
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*plainchar++ |= (fragment & 0x030) >> 4;
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*plainchar = (fragment & 0x00f) << 4;
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case step_c:
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do {
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if (codechar == code_in+length_in){
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state_in->step = step_c;
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state_in->plainchar = *plainchar;
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return plainchar - plaintext_out;
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}
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fragment = (int8_t)base64_decode_value_signed(*codechar++);
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} while (fragment < 0);
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*plainchar++ |= (fragment & 0x03c) >> 2;
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*plainchar = (fragment & 0x003) << 6;
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case step_d:
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do {
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if (codechar == code_in+length_in){
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state_in->step = step_d;
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state_in->plainchar = *plainchar;
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return plainchar - plaintext_out;
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}
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fragment = (int8_t)base64_decode_value_signed(*codechar++);
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} while (fragment < 0);
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*plainchar++ |= (fragment & 0x03f);
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}
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}
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/* control should not reach here */
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return plainchar - plaintext_out;
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}
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static int base64_decode_chars_signed(const int8_t* code_in, const int length_in, int8_t* plaintext_out){
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base64_decodestate _state;
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base64_init_decodestate(&_state);
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int len = base64_decode_block_signed(code_in, length_in, plaintext_out, &_state);
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if(len > 0) plaintext_out[len] = 0;
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return len;
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}
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int base64_decode_value(char value_in){
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return base64_decode_value_signed(*((int8_t *) &value_in));
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}
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int base64_decode_block(const char* code_in, const int length_in, char* plaintext_out, base64_decodestate* state_in){
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return base64_decode_block_signed((int8_t *) code_in, length_in, (int8_t *) plaintext_out, state_in);
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}
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int base64_decode_chars(const char* code_in, const int length_in, char* plaintext_out){
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return base64_decode_chars_signed((int8_t *) code_in, length_in, (int8_t *) plaintext_out);
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}
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