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reshape bits parsers

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This commit is contained in:
Sven M. Hallberg 2013-05-14 17:20:05 +02:00
parent c794be5b6f
commit d081cf4284
3 changed files with 58 additions and 2 deletions
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40
src/parsers/bits.c
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@ -17,6 +17,41 @@ static HParseResult* parse_bits(void* env, HParseState *state) {
return make_result(state->arena, result);
}
static HParsedToken *reshape_bits(const HParseResult *p, bool signedp) {
// XXX works only for whole bytes
// XXX assumes big-endian
assert(p->ast);
assert(p->ast->token_type == TT_SEQUENCE);
HCountedArray *seq = p->ast->seq;
HParsedToken *ret = h_arena_malloc(p->arena, sizeof(HParsedToken));
ret->token_type = TT_UINT;
if(signedp && (seq->elements[0]->uint & 128))
ret->uint = -1; // all ones
for(size_t i=0; i<seq->used; i++) {
HParsedToken *t = seq->elements[i];
assert(t->token_type == TT_UINT);
ret->uint <<= 8;
ret->uint |= t->uint & 0xFF;
}
if(signedp) {
ret->token_type = TT_SINT;
ret->sint = ret->uint;
}
return ret;
}
static const HParsedToken *reshape_bits_unsigned(const HParseResult *p) {
return reshape_bits(p, false);
}
static const HParsedToken *reshape_bits_signed(const HParseResult *p) {
return reshape_bits(p, true);
}
static HCFChoice* desugar_bits(HAllocator *mm__, void *env) {
struct bits_env *bits = (struct bits_env*)env;
if (0 != bits->length % 8)
@ -46,6 +81,11 @@ static HCFChoice* desugar_bits(HAllocator *mm__, void *env) {
ret->seq[1] = NULL;
ret->action = NULL;
if(bits->signedp)
ret->reshape = reshape_bits_signed;
else
ret->reshape = reshape_bits_unsigned;
return ret;
}