128 lines
3.7 KiB
C++
128 lines
3.7 KiB
C++
/*
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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 <Platform.h> // Only use angled for Platform, else, xcode project won't compile
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#include "b64cdecode.h"
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int base64_decode_value(char value_in)
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{
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static const signed char 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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int value_in_i = (unsigned char) value_in;
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value_in_i -= 43;
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if (value_in_i < 0 || (unsigned int) value_in_i >= sizeof decoding) return -1;
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return decoding[value_in_i];
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}
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void base64_init_decodestate(base64_decodestate* state_in)
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{
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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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long base64_decode_block(const char* code_in, const int length_in, char* plaintext_out, base64_decodestate* state_in)
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{
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const char* codechar = code_in;
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char* plainchar = plaintext_out;
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int fragment;
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*plainchar = state_in->plainchar;
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switch (state_in->step)
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{
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while (1)
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{
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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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{
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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 = base64_decode_value(*codechar++);
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} while (fragment < 0);
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*plainchar = (char) ((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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{
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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 = base64_decode_value(*codechar++);
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} while (fragment < 0);
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*plainchar++ |= (char) ((fragment & 0x030) >> 4);
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*plainchar = (char) ((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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{
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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 = base64_decode_value(*codechar++);
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} while (fragment < 0);
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*plainchar++ |= (char) ((fragment & 0x03c) >> 2);
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*plainchar = (char) ((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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{
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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 = base64_decode_value(*codechar++);
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} while (fragment < 0);
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*plainchar++ |= (char) ((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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/** UEFI interface to base54 decode.
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* Decodes EncodedData into a new allocated buffer and returns it. Caller is responsible to FreePool() it.
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* If DecodedSize != NULL, then size od decoded data is put there.
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* If return value is not NULL, DecodedSize IS > 0
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*/
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UINT8 *Base64DecodeClover(IN CONST CHAR8 *EncodedData, OUT UINTN *DecodedSize)
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{
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UINTN EncodedSize;
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INTN DecodedSizeInternal;
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UINT8 *DecodedData;
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base64_decodestate state_in;
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if (EncodedData == NULL) {
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return NULL;
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}
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EncodedSize = strlen(EncodedData);
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if (EncodedSize == 0) {
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return NULL;
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}
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// to simplify, we'll allocate the same size, although smaller size is needed
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DecodedData = (__typeof__(DecodedData))AllocateZeroPool(EncodedSize);
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base64_init_decodestate(&state_in);
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DecodedSizeInternal = base64_decode_block(EncodedData, (const int)EncodedSize, (char*) DecodedData, &state_in);
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if ( DecodedSizeInternal == 0 ) {
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FreePool(DecodedData);
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DecodedData = NULL;
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}
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if (DecodedSize != NULL) {
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if ( DecodedSizeInternal < 0 ) panic("Base64DecodeClover : DecodedSizeInternal < 0");
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*DecodedSize = (UINTN)DecodedSizeInternal;
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}
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return DecodedData;
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}
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