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generalize act_base64_n

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Sven M. Hallberg 2013-01-11 00:41:34 +01:00
parent 54bd5a4a38
commit 97b13672ce
1 changed files with 32 additions and 51 deletions
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83
examples/base64_sem1.c
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@ -78,70 +78,51 @@ const HParsedToken *act_bsfdig(const HParseResult *p)
#define act_document act_index0 #define act_document act_index0
// helper // General-form action to turn a block of base64 digits into bytes.
void carray_append_uint(HCountedArray *array, uint8_t value) const HParsedToken *act_base64_n(int n, const HParseResult *p)
{ {
HParsedToken *item = h_arena_malloc(array->arena, sizeof(HParsedToken)); assert(p->ast->token_type == TT_SEQUENCE);
item->token_type = TT_UINT;
item->uint = value; HParsedToken *res = h_arena_malloc(p->arena, sizeof(HParsedToken));
h_carray_append(array, item); res->token_type = TT_SEQUENCE;
res->seq = h_carray_new_sized(p->arena, n);
HParsedToken **digits = p->ast->seq->elements;
uint32_t x = 0;
int bits = 0;
for(int i=0; i<n+1; i++) {
x <<= 6; x |= digits[i]->uint;
bits += 6;
}
x >>= bits%8; // align, i.e. cut off extra bits
for(int i=0; i<n; i++) {
HParsedToken *item = h_arena_malloc(p->arena, sizeof(HParsedToken));
item->token_type = TT_UINT;
item->uint = x & 0xFF;
res->seq->elements[n-1-i] = item; // output the last byte and
x >>= 8; // discard it
}
res->seq->used = n;
return res;
} }
const HParsedToken *act_base64_3(const HParseResult *p) const HParsedToken *act_base64_3(const HParseResult *p)
{ {
assert(p->ast->token_type == TT_SEQUENCE); return act_base64_n(3, p);
HParsedToken *res = h_arena_malloc(p->arena, sizeof(HParsedToken));
res->token_type = TT_SEQUENCE;
res->seq = h_carray_new_sized(p->arena, 4);
HParsedToken **digits = p->ast->seq->elements;
uint32_t x = digits[0]->uint;
x <<= 6; x |= digits[1]->uint;
x <<= 6; x |= digits[2]->uint;
x <<= 6; x |= digits[3]->uint;
carray_append_uint(res->seq, (x >> 16) & 0xFF);
carray_append_uint(res->seq, (x >> 8) & 0xFF);
carray_append_uint(res->seq, x & 0xFF);
return res;
} }
const HParsedToken *act_base64_2(const HParseResult *p) const HParsedToken *act_base64_2(const HParseResult *p)
{ {
assert(p->ast->token_type == TT_SEQUENCE); return act_base64_n(2, p);
HParsedToken *res = h_arena_malloc(p->arena, sizeof(HParsedToken));
res->token_type = TT_SEQUENCE;
res->seq = h_carray_new_sized(p->arena, 4);
HParsedToken **digits = p->ast->seq->elements;
uint32_t x = digits[0]->uint;
x <<= 6; x |= digits[1]->uint;
x <<= 6; x |= digits[2]->uint;
carray_append_uint(res->seq, (x >> 10) & 0xFF);
carray_append_uint(res->seq, (x >> 2) & 0xFF);
return res;
} }
const HParsedToken *act_base64_1(const HParseResult *p) const HParsedToken *act_base64_1(const HParseResult *p)
{ {
assert(p->ast->token_type == TT_SEQUENCE); return act_base64_n(1, p);
HParsedToken *res = h_arena_malloc(p->arena, sizeof(HParsedToken));
res->token_type = TT_SEQUENCE;
res->seq = h_carray_new_sized(p->arena, 4);
HParsedToken **digits = p->ast->seq->elements;
uint32_t x = digits[0]->uint;
x <<= 6; x |= digits[1]->uint;
carray_append_uint(res->seq, (x >> 4) & 0xFF);
return res;
} }
#if 0 #if 0