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rules: use goto instead of state variable 

There's no noticeable speed difference, but I think it's nicer and more
explicit than the previous code. Some people just don't like goto,
though..

Signed-off-by: Ran Benita <ran234@gmail.com>
master
Ran Benita 2012-08-28 18:04:25 +03:00
parent 0071227e7f
commit 3b6b214c78
1 changed files with 134 additions and 159 deletions
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293
src/xkbcomp/rules.c
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@ -412,6 +412,7 @@ struct matcher {
/* Input.*/
struct rule_names rmlvo;
struct location loc;
union lvalue val;
struct scanner scanner;
darray(struct group) groups;
/* Current mapping. */
@ -999,179 +1000,153 @@ matcher_rule_apply_if_matches(struct matcher *m)
m->mapping.skip = true;
}
enum rules_state {
STATE_INITIAL = 0,
STATE_BANG,
STATE_GROUP_NAME,
STATE_GROUP_ELEMENT,
STATE_MAPPING_MLVO,
STATE_MAPPING_KCCGST,
STATE_RULE_MLVO_FIRST,
STATE_RULE_MLVO,
STATE_RULE_KCCGST,
};
static enum rules_token
gettok(struct matcher *m)
{
return lex(&m->scanner, &m->val, &m->loc);
}
static bool
matcher_match(struct matcher *m, const char *string, size_t len,
const char *file_name, struct xkb_component_names *out)
{
enum rules_token tok;
enum rules_state state = STATE_INITIAL;
union lvalue val;
if (!m)
return false;
scanner_init(&m->scanner, m->ctx, string, len, file_name);
memset(&val, 0, sizeof(val));
while ((tok = lex(&m->scanner, &val, &m->loc)) != TOK_END_OF_FILE)
{
if (tok == TOK_ERROR)
goto error;
switch (state) {
case STATE_INITIAL:
switch (tok) {
case TOK_BANG:
state = STATE_BANG;
break;
case TOK_END_OF_LINE:
state = STATE_INITIAL;
break;
default:
goto state_error;
}
break;
case STATE_BANG:
switch (tok) {
case TOK_GROUP_NAME:
matcher_group_start_new(m, val.string);
state = STATE_GROUP_NAME;
break;
case TOK_IDENTIFIER:
matcher_mapping_start_new(m);
matcher_mapping_set_mlvo(m, val.string);
state = STATE_MAPPING_MLVO;
break;
default:
goto state_error;
}
break;
case STATE_GROUP_NAME:
switch (tok) {
case TOK_EQUALS:
state = STATE_GROUP_ELEMENT;
break;
default:
goto state_error;
}
break;
case STATE_GROUP_ELEMENT:
switch (tok) {
case TOK_IDENTIFIER:
matcher_group_add_element(m, val.string);
state = STATE_GROUP_ELEMENT;
break;
case TOK_END_OF_LINE:
state = STATE_INITIAL;
break;
default:
goto state_error;
}
break;
case STATE_MAPPING_MLVO:
switch (tok) {
case TOK_IDENTIFIER:
if (!m->mapping.skip)
matcher_mapping_set_mlvo(m, val.string);
state = STATE_MAPPING_MLVO;
break;
case TOK_EQUALS:
state = STATE_MAPPING_KCCGST;
break;
default:
goto state_error;
}
break;
case STATE_MAPPING_KCCGST:
switch (tok) {
case TOK_IDENTIFIER:
if (!m->mapping.skip)
matcher_mapping_set_kccgst(m, val.string);
state = STATE_MAPPING_KCCGST;
break;
case TOK_END_OF_LINE:
if (!m->mapping.skip)
matcher_mapping_verify(m);
state = STATE_RULE_MLVO_FIRST;
break;
default:
goto state_error;
}
break;
case STATE_RULE_MLVO_FIRST:
if (tok == TOK_BANG) {
state = STATE_BANG;
break;
} else if (tok == TOK_END_OF_LINE) {
state = STATE_INITIAL;
break;
}
matcher_rule_start_new(m);
/* fallthrough */
case STATE_RULE_MLVO:
switch (tok) {
case TOK_IDENTIFIER:
if (!m->rule.skip)
matcher_rule_set_mlvo(m, val.string);
state = STATE_RULE_MLVO;
break;
case TOK_STAR:
if (!m->rule.skip)
matcher_rule_set_mlvo_wildcard(m);
state = STATE_RULE_MLVO;
break;
case TOK_GROUP_NAME:
if (!m->rule.skip)
matcher_rule_set_mlvo_group(m, val.string);
state = STATE_RULE_MLVO;
break;
case TOK_EQUALS:
state = STATE_RULE_KCCGST;
break;
default:
goto state_error;
}
break;
case STATE_RULE_KCCGST:
switch (tok) {
case TOK_IDENTIFIER:
if (!m->rule.skip)
matcher_rule_set_kccgst(m, val.string);
state = STATE_RULE_KCCGST;
break;
case TOK_END_OF_LINE:
if (!m->rule.skip)
matcher_rule_verify(m);
if (!m->rule.skip)
matcher_rule_apply_if_matches(m);
state = STATE_RULE_MLVO_FIRST;
break;
default:
goto state_error;
}
break;
}
initial:
switch (tok = gettok(m)) {
case TOK_BANG:
goto bang;
case TOK_END_OF_LINE:
goto initial;
case TOK_END_OF_FILE:
goto finish;
default:
goto unexpected;
}
bang:
switch (tok = gettok(m)) {
case TOK_GROUP_NAME:
matcher_group_start_new(m, m->val.string);
goto group_name;
case TOK_IDENTIFIER:
matcher_mapping_start_new(m);
matcher_mapping_set_mlvo(m, m->val.string);
goto mapping_mlvo;
default:
goto unexpected;
}
group_name:
switch (tok = gettok(m)) {
case TOK_EQUALS:
goto group_element;
default:
goto unexpected;
}
group_element:
switch (tok = gettok(m)) {
case TOK_IDENTIFIER:
matcher_group_add_element(m, m->val.string);
goto group_element;
case TOK_END_OF_LINE:
goto initial;
default:
goto unexpected;
}
mapping_mlvo:
switch (tok = gettok(m)) {
case TOK_IDENTIFIER:
if (!m->mapping.skip)
matcher_mapping_set_mlvo(m, m->val.string);
goto mapping_mlvo;
case TOK_EQUALS:
goto mapping_kccgst;
default:
goto unexpected;
}
mapping_kccgst:
switch (tok = gettok(m)) {
case TOK_IDENTIFIER:
if (!m->mapping.skip)
matcher_mapping_set_kccgst(m, m->val.string);
goto mapping_kccgst;
case TOK_END_OF_LINE:
if (!m->mapping.skip)
matcher_mapping_verify(m);
goto rule_mlvo_first;
default:
goto unexpected;
}
rule_mlvo_first:
switch (tok = gettok(m)) {
case TOK_BANG:
goto bang;
case TOK_END_OF_LINE:
goto rule_mlvo_first;
case TOK_END_OF_FILE:
goto finish;
default:
matcher_rule_start_new(m);
goto rule_mlvo_no_tok;
}
rule_mlvo:
tok = gettok(m);
rule_mlvo_no_tok:
switch (tok) {
case TOK_IDENTIFIER:
if (!m->rule.skip)
matcher_rule_set_mlvo(m, m->val.string);
goto rule_mlvo;
case TOK_STAR:
if (!m->rule.skip)
matcher_rule_set_mlvo_wildcard(m);
goto rule_mlvo;
case TOK_GROUP_NAME:
if (!m->rule.skip)
matcher_rule_set_mlvo_group(m, m->val.string);
goto rule_mlvo;
case TOK_EQUALS:
goto rule_kccgst;
default:
goto unexpected;
}
rule_kccgst:
switch (tok = gettok(m)) {
case TOK_IDENTIFIER:
if (!m->rule.skip)
matcher_rule_set_kccgst(m, m->val.string);
goto rule_kccgst;
case TOK_END_OF_LINE:
if (!m->rule.skip)
matcher_rule_verify(m);
if (!m->rule.skip)
matcher_rule_apply_if_matches(m);
goto rule_mlvo_first;
default:
goto unexpected;
}
unexpected:
switch (tok) {
case TOK_ERROR:
goto error;
default:
goto state_error;
}
finish:
if (darray_empty(m->kccgst[KCCGST_KEYCODES]) ||
darray_empty(m->kccgst[KCCGST_TYPES]) ||
darray_empty(m->kccgst[KCCGST_COMPAT]) ||