xref: /aosp_15_r20/external/llvm-libc/test/src/stdio/ftell_test.cpp (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
1 //===-- Unittests for ftell -----------------------------------------------===//
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 #include "hdr/stdio_macros.h"
10 #include "src/stdio/fclose.h"
11 #include "src/stdio/fopen.h"
12 #include "src/stdio/fread.h"
13 #include "src/stdio/fseek.h"
14 #include "src/stdio/fseeko.h"
15 #include "src/stdio/ftell.h"
16 #include "src/stdio/ftello.h"
17 #include "src/stdio/fwrite.h"
18 #include "src/stdio/setvbuf.h"
19 #include "test/UnitTest/Test.h"
20 
21 class LlvmLibcFTellTest : public LIBC_NAMESPACE::testing::Test {
22 protected:
test_with_bufmode(int bufmode)23   void test_with_bufmode(int bufmode) {
24     constexpr char FILENAME[] = "testdata/ftell.test";
25     // We will set a special buffer to the file so that we guarantee buffering.
26     constexpr size_t BUFFER_SIZE = 1024;
27     char buffer[BUFFER_SIZE];
28     ::FILE *file = LIBC_NAMESPACE::fopen(FILENAME, "w+");
29     ASSERT_FALSE(file == nullptr);
30     ASSERT_EQ(LIBC_NAMESPACE::setvbuf(file, buffer, bufmode, BUFFER_SIZE), 0);
31 
32     // Include few '\n' chars to test when |bufmode| is _IOLBF.
33     constexpr char CONTENT[] = "12\n345\n6789";
34     constexpr size_t WRITE_SIZE = sizeof(CONTENT) - 1;
35     ASSERT_EQ(WRITE_SIZE, LIBC_NAMESPACE::fwrite(CONTENT, 1, WRITE_SIZE, file));
36     // The above write should have buffered the written data and not have
37     // trasferred it to the underlying stream. But, ftell operation should
38     // still return the correct effective offset.
39     ASSERT_EQ(size_t(LIBC_NAMESPACE::ftell(file)), WRITE_SIZE);
40 
41     off_t offseto = 5;
42     ASSERT_EQ(0, LIBC_NAMESPACE::fseeko(file, offseto, SEEK_SET));
43     ASSERT_EQ(LIBC_NAMESPACE::ftello(file), offseto);
44     ASSERT_EQ(0, LIBC_NAMESPACE::fseeko(file, -offseto, SEEK_END));
45     ASSERT_EQ(size_t(LIBC_NAMESPACE::ftello(file)),
46               size_t(WRITE_SIZE - offseto));
47 
48     long offset = 5;
49     ASSERT_EQ(0, LIBC_NAMESPACE::fseek(file, offset, SEEK_SET));
50     ASSERT_EQ(LIBC_NAMESPACE::ftell(file), offset);
51     ASSERT_EQ(0, LIBC_NAMESPACE::fseek(file, -offset, SEEK_END));
52     ASSERT_EQ(size_t(LIBC_NAMESPACE::ftell(file)), size_t(WRITE_SIZE - offset));
53 
54     ASSERT_EQ(0, LIBC_NAMESPACE::fseek(file, 0, SEEK_SET));
55     constexpr size_t READ_SIZE = WRITE_SIZE / 2;
56     char data[READ_SIZE];
57     // Reading a small amount will actually read out much more data and
58     // buffer it. But, ftell should return the correct effective offset.
59     ASSERT_EQ(READ_SIZE, LIBC_NAMESPACE::fread(data, 1, READ_SIZE, file));
60     ASSERT_EQ(size_t(LIBC_NAMESPACE::ftell(file)), READ_SIZE);
61 
62     ASSERT_EQ(0, LIBC_NAMESPACE::fclose(file));
63   }
64 };
65 
TEST_F(LlvmLibcFTellTest,TellWithFBF)66 TEST_F(LlvmLibcFTellTest, TellWithFBF) { test_with_bufmode(_IOFBF); }
67 
TEST_F(LlvmLibcFTellTest,TellWithNBF)68 TEST_F(LlvmLibcFTellTest, TellWithNBF) { test_with_bufmode(_IONBF); }
69 
TEST_F(LlvmLibcFTellTest,TellWithLBF)70 TEST_F(LlvmLibcFTellTest, TellWithLBF) { test_with_bufmode(_IOLBF); }
71