HParsedToken *act_base64(const HParseResult *p, void* user_data)
{
assert(p->ast->token_type == TT_SEQUENCE);
assert(p->ast->seq->used == 2);
assert(p->ast->seq->elements[0]->token_type == TT_SEQUENCE);
// grab b64_3 block sequence
// grab and analyze b64 end block (_2 or _1)
const HParsedToken *b64_3 = p->ast->seq->elements[0];
const HParsedToken *b64_2 = p->ast->seq->elements[1];
const HParsedToken *b64_1 = p->ast->seq->elements[1];
if(b64_2->token_type != TT_SEQUENCE)
b64_1 = b64_2 = NULL;
else if(b64_2->seq->elements[2]->uint == '=')
b64_2 = NULL;
else
b64_1 = NULL;
// allocate result sequence
HParsedToken *res = H_MAKE_SEQ();
// concatenate base64_3 blocks
for(size_t i=0; i<b64_3->seq->used; i++) {
assert(b64_3->seq->elements[i]->token_type == TT_SEQUENCE);
HParsedToken **digits = b64_3->seq->elements[i]->seq->elements;
uint32_t x = bsfdig_value(digits[0]);
x <<= 6; x |= bsfdig_value(digits[1]);
x <<= 6; x |= bsfdig_value(digits[2]);
x <<= 6; x |= bsfdig_value(digits[3]);
seq_append_byte(res, (x >> 16) & 0xFF);
seq_append_byte(res, (x >> 8) & 0xFF);
seq_append_byte(res, x & 0xFF);
}
// append one trailing base64_2 or _1 block
if(b64_2) {
HParsedToken **digits = b64_2->seq->elements;
uint32_t x = bsfdig_value(digits[0]);
x <<= 6; x |= bsfdig_value(digits[1]);
x <<= 6; x |= bsfdig_value(digits[2]);
seq_append_byte(res, (x >> 10) & 0xFF);
seq_append_byte(res, (x >> 2) & 0xFF);
} else if(b64_1) {
const HParsedToken *act_base64(const HParseResult *p)
{
assert(p->ast->token_type == TT_SEQUENCE);
assert(p->ast->seq->used == 2);
assert(p->ast->seq->elements[0]->token_type == TT_SEQUENCE);
HParsedToken *res = H_MAKE_SEQ();
// concatenate base64_3 blocks
HCountedArray *seq = H_FIELD_SEQ(0);
for(size_t i=0; i<seq->used; i++)
h_seq_append(res, seq->elements[i]);
// append one trailing base64_2 or _1 block
const HParsedToken *tok = h_seq_index(p->ast, 1);
if(tok->token_type == TT_SEQUENCE)
h_seq_append(res, tok);
return res;
}