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/*******************************************************************\
Module: Unit tests for sparse arrays in
solvers/refinement/string_refinement.cpp
Author: Romain Brenguier, romain.brenguier@diffblue.com
\*******************************************************************/
#include <testing-utils/use_catch.h>
#include <solvers/sat/satcheck.h>
#include <solvers/strings/string_refinement.h>
#include <util/arith_tools.h>
#include <util/c_types.h>
#include <util/config.h>
#include <util/mathematical_types.h>
#include <util/std_expr.h>
#include <util/symbol_table.h>
SCENARIO("string refinement", "[core][solvers][strings][string_refinement]")
{
config.set_arch("none");
string_refinementt::infot info;
null_message_handlert log{};
info.message_handler = &log;
symbol_tablet symbol_table;
namespacet ns{symbol_table};
info.ns = &ns;
satcheckt sat_solver{log};
info.prop = &sat_solver;
string_refinementt solver{info};
GIVEN("An array of characters, with its associated pointer and length")
{
const signedbv_typet int_type{64};
const unsignedbv_typet char_type{16};
const array_typet char_array_type{char_type, infinity_exprt{int_type}};
const refined_string_typet string_type{int_type, pointer_type(char_type)};
const symbol_exprt array1{"array1", char_array_type};
const symbol_exprt pointer1{"pointer1", pointer_type(char_type)};
const symbol_exprt length1{"length1", int_type};
const refined_string_exprt string_expr{length1, pointer1, string_type};
// associate_array_to_pointer : (char[], *char) -> int
const symbol_exprt associate_array_to_pointer{
ID_cprover_associate_array_to_pointer_func,
mathematical_function_typet{{char_array_type, pointer_type(char_type)},
int_type}};
// associate_length_to_array : (int, char[]) -> int
const symbol_exprt associate_length_to_array{
ID_cprover_associate_length_to_array_func,
mathematical_function_typet{{int_type, char_array_type}, int_type}};
// length_function : (string) -> int
const symbol_exprt length_function{
ID_cprover_string_length_func,
mathematical_function_typet{{string_type}, int_type}};
// char_at_function : (string, int) -> char
const symbol_exprt char_at_function{
ID_cprover_string_char_at_func,
mathematical_function_typet{{string_type, int_type}, char_type}};
// return_code1 == associate_array_to_pointer(array1, pointer1)
const symbol_exprt return_code1{"return_code1", int_type};
solver.set_to(
equal_exprt{
return_code1,
function_application_exprt{associate_array_to_pointer,
std::vector<exprt>{array1, pointer1}}},
true);
// return_code2 == associate_length_to_array(length1, array1)
const symbol_exprt return_code2{"return_code2", int_type};
solver.set_to(
equal_exprt{
return_code1,
function_application_exprt{associate_length_to_array,
std::vector<exprt>{array1, length1}}},
true);
WHEN(
"return_length == string_length({length1, pointer1}) "
"and return_length == 15")
{
const symbol_exprt return_length{"return_length", int_type};
solver.set_to(
equal_exprt{return_length,
function_application_exprt{
length_function, std::vector<exprt>{string_expr}}},
true);
solver.set_to(
equal_exprt{return_length, from_integer(15, int_type)}, true);
auto result = solver();
THEN("The formula is satisfiable")
{
REQUIRE(result == decision_proceduret::resultt::D_SATISFIABLE);
}
THEN("the model for the result and length1 are `15`")
{
const exprt return_length_model = solver.get(return_length);
REQUIRE(return_length_model == from_integer(15, int_type));
const exprt length1_model = solver.get(length1);
REQUIRE(return_length_model == from_integer(15, int_type));
}
THEN("the model of array1 is an array of length 15")
{
const exprt array_model = solver.get(array1);
REQUIRE(can_cast_expr<array_exprt>(array_model));
REQUIRE(to_array_expr(array_model).operands().size() == 15);
}
}
WHEN("length1 == 10 and 'b' == string_char_at({length1, pointer1}, 9)")
{
solver.set_to(equal_exprt{length1, from_integer(10, int_type)}, true);
solver.set_to(
equal_exprt{
from_integer('b', char_type),
function_application_exprt{
char_at_function,
std::vector<exprt>{string_expr, from_integer(9, int_type)}}},
true);
THEN(
"The formula is satisfiable and the model of the array should have"
"length 10 and end with 'b'")
{
auto result = solver();
REQUIRE(result == decision_proceduret::resultt::D_SATISFIABLE);
const exprt array_model = solver.get(array1);
REQUIRE(can_cast_expr<array_exprt>(array_model));
const std::vector<exprt> &elements =
to_array_expr(array_model).operands();
REQUIRE(elements.size() == 10);
REQUIRE(elements[9].is_constant());
REQUIRE(numeric_cast_v<char>(to_constant_expr(elements[9])) == 'b');
}
}
WHEN(
"g1 => length1 = 10 && 'b' == string_char_at({length1, pointer1}, 9)"
" and g2 => 'c' == string_char_at({length1, pointer1}, 3)"
" and g1 && g2")
{
const symbol_exprt g1{"g1", bool_typet{}};
solver.set_to(
implies_exprt{
g1,
and_exprt{equal_exprt{length1, from_integer(10, int_type)},
equal_exprt{from_integer('b', char_type),
function_application_exprt{
char_at_function,
std::vector<exprt>{
string_expr, from_integer(9, int_type)}}}}},
true);
const symbol_exprt g2{"g2", bool_typet{}};
solver.set_to(
implies_exprt{
g2,
and_exprt{equal_exprt{length1, from_integer(10, int_type)},
equal_exprt{from_integer('c', char_type),
function_application_exprt{
char_at_function,
std::vector<exprt>{
string_expr, from_integer(3, int_type)}}}}},
true);
solver.set_to(and_exprt{g1, g2}, true);
THEN(
"The model for array1 has length 10 and contains 'c' at "
" position 3 and b at position 9")
{
auto result = solver();
REQUIRE(result == decision_proceduret::resultt::D_SATISFIABLE);
const exprt array_model = solver.get(array1);
REQUIRE(can_cast_expr<array_exprt>(array_model));
const std::vector<exprt> &elements =
to_array_expr(array_model).operands();
REQUIRE(elements.size() == 10);
REQUIRE(elements[3].is_constant());
REQUIRE(numeric_cast_v<char>(to_constant_expr(elements[3])) == 'c');
REQUIRE(elements[9].is_constant());
REQUIRE(numeric_cast_v<char>(to_constant_expr(elements[9])) == 'b');
}
}
WHEN(
"g1 => 'b' == string_char_at({length1, pointer1}, 9)"
" and g2 => 'c' == string_char_at({length1, pointer1}, 9) "
" and length1 == 10 && !g1 && g2")
{
const symbol_exprt g1{"g1", bool_typet{}};
solver.set_to(
implies_exprt{
g1,
equal_exprt{
from_integer('b', char_type),
function_application_exprt{
char_at_function,
std::vector<exprt>{string_expr, from_integer(9, int_type)}}}},
true);
const symbol_exprt g2{"g2", bool_typet{}};
solver.set_to(
implies_exprt{
g2,
equal_exprt{
from_integer('c', char_type),
function_application_exprt{
char_at_function,
std::vector<exprt>{string_expr, from_integer(9, int_type)}}}},
true);
solver.set_to(
and_exprt{
equal_exprt{length1, from_integer(10, int_type)}, not_exprt{g1}, g2},
true);
THEN("The model for array1 has length 10 and contains 'c' at position 9")
{
auto result = solver();
REQUIRE(result == decision_proceduret::resultt::D_SATISFIABLE);
const exprt array_model = solver.get(array1);
REQUIRE(can_cast_expr<array_exprt>(array_model));
const std::vector<exprt> &elements =
to_array_expr(array_model).operands();
REQUIRE(elements.size() == 10);
REQUIRE(elements[9].is_constant());
REQUIRE(numeric_cast_v<char>(to_constant_expr(elements[9])) == 'c');
}
}
}
}
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