69 lines · cpp
1//===-- Unittests for ungetc ----------------------------------------------===//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-exception6//7//===----------------------------------------------------------------------===//8 9#include "src/stdio/ungetc.h"10 11#include "hdr/stdio_macros.h"12#include "src/stdio/fclose.h"13#include "src/stdio/fopen.h"14#include "src/stdio/fread.h"15#include "src/stdio/fseek.h"16#include "src/stdio/fwrite.h"17#include "test/UnitTest/Test.h"18 19TEST(LlvmLibcUngetcTest, UngetAndReadBack) {20 constexpr char FILENAME[] = APPEND_LIBC_TEST("testdata/ungetc_test.test");21 ::FILE *file = LIBC_NAMESPACE::fopen(FILENAME, "w");22 ASSERT_FALSE(file == nullptr);23 constexpr char CONTENT[] = "abcdef";24 constexpr size_t CONTENT_SIZE = sizeof(CONTENT);25 ASSERT_EQ(CONTENT_SIZE,26 LIBC_NAMESPACE::fwrite(CONTENT, 1, CONTENT_SIZE, file));27#ifndef LIBC_TARGET_ARCH_IS_GPU // Behavior varies between libc implementations.28 // Cannot unget to an un-readable file.29 ASSERT_EQ(EOF, LIBC_NAMESPACE::ungetc('1', file));30#endif31 ASSERT_EQ(0, LIBC_NAMESPACE::fclose(file));32 33 file = LIBC_NAMESPACE::fopen(FILENAME, "r+");34 ASSERT_FALSE(file == nullptr);35 // Calling with an EOF should always return EOF without doing anything.36 ASSERT_EQ(EOF, LIBC_NAMESPACE::ungetc(EOF, file));37 char c;38 ASSERT_EQ(LIBC_NAMESPACE::fread(&c, 1, 1, file), size_t(1));39 ASSERT_EQ(c, CONTENT[0]);40 ASSERT_EQ(LIBC_NAMESPACE::ungetc(int(c), file), int(c));41 42 char data[CONTENT_SIZE];43 ASSERT_EQ(CONTENT_SIZE, LIBC_NAMESPACE::fread(data, 1, CONTENT_SIZE, file));44 ASSERT_STREQ(CONTENT, data);45 46 ASSERT_EQ(0, LIBC_NAMESPACE::fseek(file, 0, SEEK_SET));47 // ungetc should not fail after a seek operation.48 int unget_char = 'z';49 ASSERT_EQ(unget_char, LIBC_NAMESPACE::ungetc(unget_char, file));50#ifndef LIBC_TARGET_ARCH_IS_GPU // Behavior varies between libc implementations.51 // Another unget should fail.52 ASSERT_EQ(EOF, LIBC_NAMESPACE::ungetc(unget_char, file));53#endif54 // ungetting a char at the beginning of the file will allow us to fetch55 // one additional character.56 char new_data[CONTENT_SIZE + 1];57 ASSERT_EQ(CONTENT_SIZE + 1,58 LIBC_NAMESPACE::fread(new_data, 1, CONTENT_SIZE + 1, file));59 ASSERT_STREQ("zabcdef", new_data);60 61 ASSERT_EQ(size_t(1), LIBC_NAMESPACE::fwrite("x", 1, 1, file));62#ifndef LIBC_TARGET_ARCH_IS_GPU // Behavior varies between libc implementations.63 // unget should fail after a write operation.64 ASSERT_EQ(EOF, LIBC_NAMESPACE::ungetc('1', file));65#endif66 67 ASSERT_EQ(0, LIBC_NAMESPACE::fclose(file));68}69