* SPDX-License-Identifier: BSD-4-Clause

/* $NetBSD: parse.c,v 1.85 2025/01/07 03:55:00 rillig Exp $ */

/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* Copyright (c) 1985 Sun Microsystems, Inc.
* Copyright (c) 1980, 1993
* The Regents of the University of California. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__RCSID("$NetBSD: parse.c,v 1.85 2025/01/07 03:55:00 rillig Exp $");

#include <stdlib.h>

#include "indent.h"

/* Replace the top 2 symbols with the given symbol. */
static void
ps_psyms_replace2(parser_symbol psym)
{
ps.psyms.len--;
ps.psyms.sym[ps.psyms.len - 1] = psym;
ps.ind_level_follow = ps.psyms.ind_level[ps.psyms.len - 1];
}

static int
left_justify_decl_level(void)
{
int level = 0;
for (size_t i = ps.psyms.len - 2; i > 0; i--)
if (ps.psyms.sym[i] == psym_decl)
level++;
return level;
}

void
ps_psyms_push(parser_symbol psym, int ind_level)
{
if (ps.psyms.len == ps.psyms.cap) {
ps.psyms.cap += 16;
ps.psyms.sym = nonnull(realloc(ps.psyms.sym,
sizeof(ps.psyms.sym[0]) * ps.psyms.cap));
ps.psyms.ind_level = nonnull(realloc(ps.psyms.ind_level,
sizeof(ps.psyms.ind_level[0]) * ps.psyms.cap));
}
ps.psyms.len++;
ps.psyms.sym[ps.psyms.len - 1] = psym;
ps.psyms.ind_level[ps.psyms.len - 1] = ind_level;
}

/*
* Repeatedly try to reduce the top two symbols on the parse stack to a single
* symbol, until no more reductions are possible.
*/
static void
psyms_reduce(void)
{
again:
if (ps.psyms.len >= 2 && ps.psyms.sym[ps.psyms.len - 1] == psym_stmt) {
switch (ps.psyms.sym[ps.psyms.len - 2]) {
case psym_decl:
case psym_stmt:
case psym_for_exprs:
case psym_if_expr_stmt_else:
case psym_switch_expr:
case psym_while_expr:
ps_psyms_replace2(psym_stmt);
goto again;
case psym_if_expr:
ps_psyms_replace2(psym_if_expr_stmt);
goto again;
case psym_do:
ps_psyms_replace2(psym_do_stmt);
goto again;
default:
return;
}
}
if (ps.psyms.sym[ps.psyms.len - 1] == psym_while_expr &&
ps.psyms.sym[ps.psyms.len - 2] == psym_do_stmt) {
ps.psyms.len -= 2;
goto again;
}
}

static bool
is_lbrace(parser_symbol psym)
{
return psym == psym_lbrace_block
|| psym == psym_lbrace_struct
|| psym == psym_lbrace_union
|| psym == psym_lbrace_enum;
}

/*
* Shift the token onto the parser stack, then try to reduce it by combining it with
* previous tokens.
*/
void
parse(parser_symbol psym)
{
debug_blank_line();
debug_println("parse: %s", psym_name[psym]);

if (psym != psym_else) {
while (ps.psyms.sym[ps.psyms.len - 1] == psym_if_expr_stmt) {
ps.psyms.sym[ps.psyms.len - 1] = psym_stmt;
psyms_reduce();
ps.ind_level = ps.ind_level_follow
= ps.psyms.ind_level[ps.psyms.len - 1];
}
}

switch (psym) {

case psym_lbrace_block:
case psym_lbrace_struct:
case psym_lbrace_union:
case psym_lbrace_enum:
ps.break_after_comma = false;
if (ps.psyms.sym[ps.psyms.len - 1] == psym_decl
|| ps.psyms.sym[ps.psyms.len - 1] == psym_stmt)
ps.ind_level_follow++;
else if (code.len == 0) {
/* It is part of a while, for, etc. */
ps.ind_level--;

/* for a switch, brace should be two levels out from
* the code */
if (ps.psyms.sym[ps.psyms.len - 1] == psym_switch_expr
&& opt.case_indent >= 1.0F)
ps.ind_level--;
}

ps_psyms_push(psym, ps.ind_level);
ps_psyms_push(psym_stmt, ps.ind_level_follow);
break;

case psym_rbrace:
/* stack should have <lbrace> <stmt> or <lbrace> <decl> */
if (!(ps.psyms.len >= 2
&& is_lbrace(ps.psyms.sym[ps.psyms.len - 2]))) {
diag(1, "Statement nesting error");
break;
}
ps_psyms_replace2(psym_stmt);
ps.ind_level = ps.ind_level_follow;
break;

case psym_decl:
if (ps.psyms.sym[ps.psyms.len - 1] == psym_decl)
break; /* only put one declaration onto stack */

ps.break_after_comma = true;
ps_psyms_push(psym_decl, ps.ind_level_follow);

if (opt.left_justify_decl) {
ps.ind_level = left_justify_decl_level();
ps.ind_level_follow = ps.ind_level;
}
break;

case psym_stmt:
ps.break_after_comma = false;
ps_psyms_push(psym_stmt, ps.ind_level);
break;

case psym_if_expr:
if (ps.psyms.sym[ps.psyms.len - 1] == psym_if_expr_stmt_else
&& opt.else_if_in_same_line) {
ps.ind_level_follow =
ps.psyms.ind_level[ps.psyms.len - 1];
ps.psyms.len--;
}
/* FALLTHROUGH */
case psym_do:
case psym_for_exprs:
ps.ind_level = ps.ind_level_follow;
ps.ind_level_follow = ps.ind_level + 1;
ps_psyms_push(psym, ps.ind_level);
break;

case psym_else:
if (ps.psyms.sym[ps.psyms.len - 1] != psym_if_expr_stmt) {
diag(1, "Unmatched 'else'");
break;
}
ps.ind_level = ps.psyms.ind_level[ps.psyms.len - 1];
ps.ind_level_follow = ps.ind_level + 1;
ps.psyms.sym[ps.psyms.len - 1] = psym_if_expr_stmt_else;
break;

case psym_switch_expr:
ps_psyms_push(psym_switch_expr, ps.ind_level_follow);
ps.ind_level_follow += (int)opt.case_indent + 1;
break;

case psym_while_expr:
if (ps.psyms.sym[ps.psyms.len - 1] == psym_do_stmt) {
ps.ind_level = ps.psyms.ind_level[ps.psyms.len - 1];
ps.ind_level_follow = ps.ind_level;
ps_psyms_push(psym_while_expr, ps.ind_level);
} else {
ps_psyms_push(psym_while_expr, ps.ind_level_follow);
ps.ind_level_follow++;
}
break;

default:
diag(1, "Unknown code to parser");
return;
}

#if debug
static struct buffer before, after;
buf_clear(&before);
ps_psyms_to_string(&before, &ps);
#endif
psyms_reduce();
#if debug
buf_clear(&after);
ps_psyms_to_string(&after, &ps);
if (strcmp(before.s, after.s) != 0) {
debug_println("psyms before: %s", before.s);
debug_println("psyms after: %s", after.s);
} else
debug_println("psyms: %s", after.s);
#endif
}