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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX26_REMOVED_CODECVT
// MSVC warning C4242: '+=': conversion from 'const _Ty' to 'size_t', possible loss of data
// MSVC warning C4244: 'argument': conversion from 'std::streamsize' to 'size_t', possible loss of data
// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4242 /wd4244
// UNSUPPORTED: c++03
// <fstream>
// This test checks the behavior of writing payloads of different sizes in different patterns.
// In particular, it was written to exercise code paths that deal with buffering inside the fstream
// implementation.
//
// For each test, we test various behaviors w.r.t. how the buffer is handled:
// - Provide a user-managed buffer to the library. In this case, we test the following corner-cases:
// + A 0-sized buffer.
// + A buffer size greater than and smaller than the payload size, which causes multiple buffer effects.
// Important values are +/- 1 byte from the payload size.
// - Let the library manage a buffer of a user-provided size 'n'. In this case, we test the following corner-cases:
// + A 0-sized buffer.
// + A buffer size greater than and smaller than the payload size, which causes multiple buffer effects.
// Important values are +/- 1 or 2 bytes from the payload size.
// + A buffer size smaller than 8 bytes. If pubsetbuf() is called with less than 8 bytes, the library will
// use __extbuf_min_ with 8 bytes instead of allocating anything.
// - Let the library manage a buffer, without specifying any size. In this case, the library will use the default
// buffer size of 4096 bytes.
#include <cassert>
#include <codecvt>
#include <fstream>
#include <locale>
#include <numeric>
#include <string>
#include <vector>
#include "../types.h"
#include "assert_macros.h"
#include "platform_support.h"
#include "test_macros.h"
template <class BufferPolicy>
void test_write(BufferPolicy policy, const std::vector<std::streamsize>& payload_sizes) {
std::size_t previously_written = 0;
std::streamsize total_size = std::accumulate(payload_sizes.begin(), payload_sizes.end(), std::streamsize{0});
std::vector<char> data(total_size);
for (std::size_t i = 0; i < data.size(); ++i) {
data[i] = static_cast<char>(i % (1 << 8 * sizeof(char)));
}
std::string p = get_temp_file_name();
{
std::ofstream ofs;
policy(ofs);
ofs.open(p, std::ios::out | std::ios::binary);
assert(ofs.is_open());
for (const auto& payload_sz : payload_sizes) {
ofs.write(data.data() + previously_written, payload_sz);
assert(!ofs.fail());
// test that the user's out_buffer buffer was not modified by write()
for (std::streamsize j = 0; j < payload_sz; ++j) {
char exp = (previously_written + j) % (1 << 8 * sizeof(char));
TEST_REQUIRE(data[previously_written + j] == exp, [&] {
test_eprintf(
"failed after write() at offset %zu (offset %zu in chunk size %zu): got=%x, expected=%x\n",
previously_written + j,
j,
payload_sz,
data[previously_written + j],
exp);
});
}
previously_written += payload_sz;
}
ofs.close();
}
{ // verify contents after reading the file back
std::ifstream ifs(p.c_str(), std::ios::ate | std::ios::binary);
const std::streamsize in_sz = ifs.tellg();
TEST_REQUIRE(in_sz == total_size, [&] { test_eprintf("out_sz = %zu, in_sz = %ld\n", total_size, in_sz); });
std::vector<char> in_buffer(total_size);
ifs.seekg(0, std::ios::beg);
assert(ifs.read(in_buffer.data(), total_size));
for (std::size_t i = 0; i < in_buffer.size(); ++i) {
char exp = i % (1 << 8 * sizeof(char));
TEST_REQUIRE(in_buffer[i] == exp, [&] {
test_eprintf("failed after read() at offset %zu: got=%x, expected=%x\n", i, in_buffer[i], exp);
});
}
}
std::remove(p.c_str());
}
#ifndef TEST_HAS_NO_WIDE_CHARACTERS
template <class BufferPolicy>
void test_write_codecvt(BufferPolicy policy, const std::vector<std::streamsize>& payload_sizes) {
std::size_t previously_written = 0;
std::streamsize total_size = std::accumulate(payload_sizes.begin(), payload_sizes.end(), std::streamsize{0});
std::vector<wchar_t> data(total_size);
for (std::size_t i = 0; i < data.size(); ++i) {
data[i] = static_cast<wchar_t>(i);
}
std::string p = get_temp_file_name();
{
std::wofstream ofs;
ofs.imbue(std::locale(std::locale::classic(), new std::codecvt_utf8<wchar_t>));
policy(ofs);
ofs.open(p, std::ios::out | std::ios::binary);
assert(ofs.is_open());
for (const auto& payload_sz : payload_sizes) {
ofs.write(data.data() + previously_written, payload_sz);
assert(!ofs.fail());
// test that the user's out_buffer buffer was not modified by write()
for (std::streamsize j = 0; j < payload_sz; ++j) {
wchar_t exp = static_cast<wchar_t>(previously_written + j);
TEST_REQUIRE(data[previously_written + j] == exp, [&] {
test_eprintf(
"failed after write() at offset %zu (offset %zu in chunk size %zu): got=%x, expected=%x\n",
previously_written + j,
j,
payload_sz,
data[previously_written + j],
exp);
});
}
previously_written += payload_sz;
}
ofs.close();
}
{ // verify contents after reading the file back
std::wifstream ifs(p.c_str(), std::ios::in | std::ios::binary);
ifs.imbue(std::locale(std::locale::classic(), new std::codecvt_utf8<wchar_t>));
std::vector<wchar_t> in_buffer(total_size);
assert(ifs.read(in_buffer.data(), total_size));
for (std::size_t i = 0; i < in_buffer.size(); ++i) {
wchar_t exp = static_cast<wchar_t>(i);
TEST_REQUIRE(in_buffer[i] == exp, [&] {
test_eprintf("failed after read() at offset %zu: got=%x, expected=%x\n", i, in_buffer[i], exp);
});
}
}
std::remove(p.c_str());
}
#endif
const std::vector<std::streamsize> buffer_sizes{0L, 3L, 8L, 9L, 11L};
const std::vector<std::streamsize> io_sizes{0L, 1L, 2L, 3L, 4L, 9L, 10L, 11L, 12L, 13L, 21L, 22L, 23L};
const std::vector<std::streamsize> io_sizes_default{
0L, 1L, 2L, 3L, 4L, 4094L, 4095L, 4096L, 4097L, 4098L, 8190L, 8191L, 8192L, 8193L, 8194L};
// Test single write operations
void test_1_write() {
// with default library buffer size: 4096b
for (std::streamsize x : io_sizes_default) {
test_write(LibraryDefaultBuffer(), {x});
#ifndef TEST_HAS_NO_WIDE_CHARACTERS
test_write_codecvt(LibraryDefaultBuffer(), {x});
#endif
}
// with the library-managed buffer of given size
for (std::streamsize b : buffer_sizes) {
for (std::streamsize x : io_sizes) {
test_write(LibraryManagedBuffer(b), {x});
#ifndef TEST_HAS_NO_WIDE_CHARACTERS
test_write_codecvt(LibraryManagedBuffer(b), {x});
#endif
}
}
// with the user-managed buffer of given size
for (std::streamsize b : buffer_sizes) {
for (std::streamsize x : io_sizes) {
test_write(UserManagedBuffer(b), {x});
#ifndef TEST_HAS_NO_WIDE_CHARACTERS
test_write_codecvt(UserManagedBuffer(b), {x});
#endif
}
}
}
// Test two write operations
void test_2_writes() {
// with default library buffer size: 4096b
for (std::streamsize a : io_sizes_default) {
for (std::streamsize b : io_sizes_default) {
test_write(LibraryDefaultBuffer(), {a, b});
#ifndef TEST_HAS_NO_WIDE_CHARACTERS
test_write_codecvt(LibraryDefaultBuffer(), {a, b});
#endif
}
}
// with the library-managed buffer of given size
for (std::streamsize buf : buffer_sizes) {
for (std::streamsize a : io_sizes) {
for (std::streamsize b : io_sizes) {
test_write(LibraryManagedBuffer(buf), {a, b});
#ifndef TEST_HAS_NO_WIDE_CHARACTERS
test_write_codecvt(LibraryManagedBuffer(buf), {a, b});
#endif
}
}
}
// with the user-managed buffer of given size
for (std::streamsize buf : buffer_sizes) {
for (std::streamsize a : io_sizes) {
for (std::streamsize b : io_sizes) {
test_write(UserManagedBuffer(buf), {a, b});
#ifndef TEST_HAS_NO_WIDE_CHARACTERS
test_write_codecvt(UserManagedBuffer(buf), {a, b});
#endif
}
}
}
}
int main(int, char**) {
test_1_write();
test_2_writes();
return 0;
}
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