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/*
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 <minizinc/_thirdparty/b64/cdecode.h>
/*
* Calculate a maximum required buffer length for decoded output based on input size.
*
* Return the value as size_t
*/
size_t base64_decode_maxlength(size_t encode_len) { return encode_len / 4 * 3 + 2; }
int base64_decode_value(signed 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};
static const char decoding_size = sizeof(decoding);
if (value_in < 43) return -1;
value_in -= 43;
if (value_in > decoding_size) return -1;
return decoding[(int)value_in];
}
void base64_init_decodestate(base64_decodestate* state_in) {
state_in->step = step_a;
state_in->plainchar = 0;
}
size_t base64_decode_block(const char* code_in, const size_t length_in, void* 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) {
for (;;) {
case step_a:
do {
if (codechar == code_in + length_in) {
state_in->step = step_a;
state_in->plainchar = *plainchar;
return (size_t)(plainchar - (char*)plaintext_out);
}
fragment = base64_decode_value(*codechar++);
} while (fragment < 0);
*plainchar = (fragment & 0x03f) << 2;
case step_b:
do {
if (codechar == code_in + length_in) {
state_in->step = step_b;
state_in->plainchar = *plainchar;
return (size_t)(plainchar - (char*)plaintext_out);
}
fragment = base64_decode_value(*codechar++);
} while (fragment < 0);
*plainchar++ |= (fragment & 0x030) >> 4;
*plainchar = (fragment & 0x00f) << 4;
case step_c:
do {
if (codechar == code_in + length_in) {
state_in->step = step_c;
state_in->plainchar = *plainchar;
return (size_t)(plainchar - (char*)plaintext_out);
}
fragment = base64_decode_value(*codechar++);
} while (fragment < 0);
*plainchar++ |= (fragment & 0x03c) >> 2;
*plainchar = (fragment & 0x003) << 6;
case step_d:
do {
if (codechar == code_in + length_in) {
state_in->step = step_d;
state_in->plainchar = *plainchar;
return (size_t)(plainchar - (char*)plaintext_out);
}
fragment = base64_decode_value(*codechar++);
} while (fragment < 0);
*plainchar++ |= (fragment & 0x03f);
}
}
/* control should not reach here */
return (size_t)(plainchar - (char*)plaintext_out);
}
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