CloverBootloader/rEFIt_UEFI/Platform/b64cdecode.c
2019-09-03 12:58:42 +03:00

121 lines
3.4 KiB
C

/*
cdecoder.c - c source to a base64 decoding algorithm implementation
This is part of the libb64 project, and has been placed in the public domain.
For details, see http://sourceforge.net/projects/libb64
*/
#include "Platform.h"
#include "b64cdecode.h"
int base64_decode_value(char value_in)
{
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};
int value_in_i = (unsigned char) value_in;
value_in_i -= 43;
if (value_in_i < 0 || (unsigned int) value_in_i >= sizeof decoding) return -1;
return decoding[value_in_i];
}
void base64_init_decodestate(base64_decodestate* state_in)
{
state_in->step = step_a;
state_in->plainchar = 0;
}
int base64_decode_block(const char* code_in, const int length_in, char* plaintext_out, base64_decodestate* state_in)
{
const char* codechar = code_in;
char* plainchar = plaintext_out;
int fragment;
*plainchar = state_in->plainchar;
switch (state_in->step)
{
while (1)
{
case step_a:
do {
if (codechar == code_in+length_in)
{
state_in->step = step_a;
state_in->plainchar = *plainchar;
return (int)(plainchar - plaintext_out);
}
fragment = base64_decode_value(*codechar++);
} while (fragment < 0);
*plainchar = (char) ((fragment & 0x03f) << 2);
case step_b:
do {
if (codechar == code_in+length_in)
{
state_in->step = step_b;
state_in->plainchar = *plainchar;
return (int)(plainchar - plaintext_out);
}
fragment = base64_decode_value(*codechar++);
} while (fragment < 0);
*plainchar++ |= (char) ((fragment & 0x030) >> 4);
*plainchar = (char) ((fragment & 0x00f) << 4);
case step_c:
do {
if (codechar == code_in+length_in)
{
state_in->step = step_c;
state_in->plainchar = *plainchar;
return (int)(plainchar - plaintext_out);
}
fragment = base64_decode_value(*codechar++);
} while (fragment < 0);
*plainchar++ |= (char) ((fragment & 0x03c) >> 2);
*plainchar = (char) ((fragment & 0x003) << 6);
case step_d:
do {
if (codechar == code_in+length_in)
{
state_in->step = step_d;
state_in->plainchar = *plainchar;
return (int)(plainchar - plaintext_out);
}
fragment = base64_decode_value(*codechar++);
} while (fragment < 0);
*plainchar++ |= (char) ((fragment & 0x03f));
}
}
/* control should not reach here */
return (int)(plainchar - plaintext_out);
}
/** UEFI interface to base54 decode.
* Decodes EncodedData into a new allocated buffer and returns it. Caller is responsible to FreePool() it.
* If DecodedSize != NULL, then size od decoded data is put there.
*/
UINT8 *Base64DecodeClover(IN CHAR8 *EncodedData, OUT UINTN *DecodedSize)
{
UINTN EncodedSize;
UINTN DecodedSizeInternal;
UINT8 *DecodedData;
base64_decodestate state_in;
if (EncodedData == NULL) {
return NULL;
}
EncodedSize = AsciiStrLen(EncodedData);
if (EncodedSize == 0) {
return NULL;
}
// to simplify, we'll allocate the same size, although smaller size is needed
DecodedData = AllocateZeroPool(EncodedSize);
base64_init_decodestate(&state_in);
DecodedSizeInternal = base64_decode_block(EncodedData, (const int)EncodedSize, (char*) DecodedData, &state_in);
if (DecodedSize != NULL) {
*DecodedSize = DecodedSizeInternal;
}
return DecodedData;
}