1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9// <fstream>
10
11// Test that we can seek using offsets larger than 32 bit, and that we can
12// retrieve file offsets larger than 32 bit.
13
14// On 32 bit Android platforms, off_t is 32 bit by default. By defining
15// _FILE_OFFSET_BITS=64, one gets a 64 bit off_t, but the corresponding
16// 64 bit ftello/fseeko functions are only available since Android API 24 (7.0).
17// (On 64 bit Android platforms, off_t has always been 64 bit.)
18//
19// XFAIL: target={{i686|arm.*}}-{{.+}}-android{{.*}}
20
21// Writing the >4 GB test file fails on 32 bit AIX.
22//
23// XFAIL: target=powerpc-{{.+}}-aix{{.*}}
24
25// By default, off_t is typically a 32-bit integer on ARMv7 Linux systems,
26// meaning it can represent file sizes up to 2GB (2^31 bytes) only.
27//
28// UNSUPPORTED: target=armv7-unknown-linux-gnueabihf
29
30#include <fstream>
31#include <iostream>
32#include <cassert>
33#include <vector>
34
35#include "assert_macros.h"
36#include "platform_support.h"
37#include "test_macros.h"
38
39void test_tellg(std::streamoff total_size) {
40 std::vector<char> data(8192);
41 for (std::size_t i = 0; i < data.size(); ++i)
42 data[i] = static_cast<char>(i % (1 << 8 * sizeof(char)));
43 std::string p = get_temp_file_name();
44 {
45 std::ofstream ofs;
46 ofs.open(s: p, mode: std::ios::out | std::ios::binary);
47 assert(ofs.is_open());
48 for (std::streamoff size = 0; size < total_size;) {
49 std::streamoff n = std::min(a: static_cast<std::streamoff>(data.size()), b: total_size - size);
50 ofs.write(s: data.data(), n: n);
51 size += n;
52 }
53 assert(!ofs.fail());
54 ofs.close();
55 }
56 {
57 std::ifstream ifs;
58 ifs.open(s: p, mode: std::ios::binary);
59 assert(ifs.is_open());
60 std::streamoff in_off = ifs.tellg();
61 TEST_REQUIRE(in_off == 0, "in_off not zero at start");
62 ifs.seekg(total_size - 20, std::ios::beg);
63 in_off = ifs.tellg();
64 TEST_REQUIRE(in_off == total_size - 20, "in_off incorrect after >32 bit seek");
65 ifs.seekg(10, std::ios::cur);
66 in_off = ifs.tellg();
67 TEST_REQUIRE(in_off == total_size - 10, "in_off incorrect after incremental seek");
68 ifs.seekg(0, std::ios::end);
69 in_off = ifs.tellg();
70 TEST_REQUIRE(in_off == total_size, "in_off incorrect after seek to end");
71 }
72 std::remove(filename: p.c_str());
73}
74
75int main(int, char**) {
76 // This test assumes and requires that std::streamoff is larger than
77 // 32 bit - this is not required in the standard itself.
78 static_assert(sizeof(std::streamoff) > 4, "");
79 test_tellg(total_size: 0x100000042ULL);
80 return 0;
81}
82

source code of libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/offset_range.pass.cpp