/**
* Skip through the text to a matching "#endif" or "#else" or
* "#elif*def". We do this when we are skipping code due to a failed
* "#if*def" test.
*/
static char *
skip_to_else_end(char * start)
{
char * scan = start;
char * res;
for (;;) {
scan = next_directive(scan);
switch (find_directive(scan)) {
case DIR_ELSE:
/*
* We found an "else" directive for an "ifdef"/"ifndef"
* that we were skipping over. Start processing the text.
* Let the @code{DIR_ENDIF} advance the scanning pointer.
*/
ifdef_lvl++;
/* FALLTHROUGH */
case DIR_ENDIF:
{
/*
* We reached the end of the "ifdef"/"ifndef" (or transitioned to
* process-the-text mode via "else"). Start processing the text.
*/
char * pz = strchr(scan, NL);
if (pz != NULL)
res = pz+1;
else res = scan + strlen(scan);
goto leave_func;
}
case DIR_IF:
skip_if_block = true;
scan = skip_to_endif(scan);
skip_if_block = false;
break;
case DIR_IFDEF:
case DIR_IFNDEF:
scan = skip_to_endif(scan);
break;
default:
/*
* We either don't know what it is or we do not care.
*/
break;
} /* switch (find_directive(scan)) */
}
leave_func:
cctx->scx_line += count_lines(start, res);
return res;
}
/**
* This must follow an @code{#if}, @code{#ifdef} or @code{#ifndef}.
* If it follows the @code{#if}, then it will be ignored. Otherwise,
* it will change the processing state to the reverse of what it was.
*/
char *
doDir_else(directive_enum_t id, char const * arg, char * scan_next)
{
if (--ifdef_lvl < 0)
return bad_dirv_ctx(id, arg, scan_next);
return skip_to_endif(scan_next);
}
/**
* @code{#if} expressions are not analyzed. @strong{Everything} from here
* to the matching @code{#endif} is skipped.
*/
char *
doDir_if(directive_enum_t id, char const * arg, char * scan_next)
{
skip_if_block = true;
scan_next = skip_to_endif(scan_next);
skip_if_block = false;
(void)arg;
(void)id;
return scan_next;
}
static void if_handle(state_t* state, match_t* match, bool* reprocess)
{
list_t* result = ppparam_get(state);
struct expr* expr = NULL;
uint16_t value;
bstring output;
bool stopped_at_else;
// Ensure the parameter format is correct.
if (list_size(result) == 1 &&
((parameter_t*)list_get_at(result, 0))->type == EXPRESSION)
{
// Get the expression.
expr = ((parameter_t*)list_get_at(result, 0))->expr;
replace_state = state;
value = expr_evaluate(expr, &if_define_replace, &dhalt_expression_exit_handler);
replace_state = NULL;
if (value)
{
output = skip_to_endif(state, true, &stopped_at_else);
if (stopped_at_else)
skip_to_endif(state, false, &stopped_at_else);
}
else
{
bassigncstr(output, "");
skip_to_endif(state, true, &stopped_at_else);
if (stopped_at_else)
{
output = skip_to_endif(state, false, &stopped_at_else);
}
}
// print the output to the pre processor input
ppimpl_printf(state, "%s", output->data);
}
else
dhalt(ERR_PP_ASM_IF_PARAMETERS_INCORRECT, ppimpl_get_location(state));
ppparam_free(result);
}
/**
* Skip through the text to a matching "#endif". We do this when we
* have processed the allowable text (found an "#else" after
* accepting the preceding text) or when encountering a "#if*def"
* while skipping a block of text due to a failed test.
*/
static char *
skip_to_endif(char * start)
{
bool skipping_if = skip_if_block;
char * scan = start;
char * dirv_end;
for (;;) {
scan = next_directive(scan);
switch (find_directive(scan)) {
case DIR_ENDIF:
{
/*
* We found the endif we are interested in
*/
char * pz = strchr(scan, NL);
if (pz != NULL)
dirv_end = pz+1;
else dirv_end = scan + strlen(scan);
goto leave_func;
}
case DIR_ELIF:
if (! skip_if_block)
AG_ABEND(ELIF_CONTEXT_MSG);
break;
case DIR_IF:
skip_if_block = true;
/* FALLTHROUGH */
case DIR_IFDEF:
case DIR_IFNDEF:
/*
* We found a nested conditional, so skip to endif nested, too.
*/
scan = skip_to_endif(scan);
skip_if_block = skipping_if;
break;
default:
/*
* We do not care what we found
*/
break; /* ignore it */
} /* switch (find_directive(scan)) */
}
leave_func:
cctx->scx_line += count_lines(start, dirv_end);
return dirv_end;
}
