#!/usr/bin/env python3
"""Guard arena_map_is_used's C89 locals and original evaluation order."""

import re
import sys
from pathlib import Path

source = Path(sys.argv[1]).read_text()
match = re.search(r"\narena_map_is_used\(block \*p\)\s*\{(.*?)\n\}", source, re.S)
assert match, "arena_map_is_used definition not found"
body = re.sub(r"/\*.*?\*/", "", match.group(1), flags=re.S)
declarations = """
    arena_map_bot_t *n = arena_map_get(p, 0);
    int i3;
    int32_t hi;
    int32_t lo;
    int32_t tail;
"""
assert body.split()[:len(declarations.split())] == declarations.split(), (
    "arena_map_is_used must declare i3, hi, lo, tail before the NULL guard"
)

# Failed lookup must return before index evaluation or node dereferences.
# Preserve lookup count, assignment order, and the short-circuit predicate.
expected = declarations + """
    if (n == NULL) {
        return 0;
    }
    i3 = MAP_BOT_INDEX(p);
    hi = n->arenas[i3].tail_hi;
    lo = n->arenas[i3].tail_lo;
    tail = (int32_t)(AS_UINT(p) & ARENA_SIZE_MASK);
    return (tail < lo) || (tail >= hi && hi != 0);
"""
assert body.split() == expected.split(), (
    "preserve arena_map_is_used lookup, NULL return, evaluation order and predicate"
)
print("obmalloc arena_map_is_used C89 declarations and original evaluation order: PASS")