04a9c62554
Fixes https://github.com/llvm/llvm-project/issues/61071 Reviewed By: sivachandra Differential Revision: https://reviews.llvm.org/D145191
56 lines
1.5 KiB
C++
56 lines
1.5 KiB
C++
//===-- Implementation of fgets -------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "src/stdio/fgets.h"
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#include "src/__support/File/file.h"
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#include "src/errno/libc_errno.h"
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#include <stddef.h>
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#include <stdio.h>
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namespace __llvm_libc {
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LLVM_LIBC_FUNCTION(char *, fgets,
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(char *__restrict str, int count,
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::FILE *__restrict raw_stream)) {
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if (count < 1)
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return nullptr;
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unsigned char c = '\0';
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auto stream = reinterpret_cast<__llvm_libc::File *__restrict>(raw_stream);
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stream->lock();
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// i is an int because it's frequently compared to count, which is also int.
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int i = 0;
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for (; i < (count - 1) && c != '\n'; ++i) {
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auto result = stream->read_unlocked(&c, 1);
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size_t r = result.value;
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if (result.has_error())
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libc_errno = result.error;
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if (r != 1)
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break;
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str[i] = c;
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}
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bool has_error = stream->error_unlocked();
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bool has_eof = stream->iseof_unlocked();
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stream->unlock();
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// If the requested read size makes no sense, an error occured, or no bytes
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// were read due to an EOF, then return nullptr and don't write the null byte.
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if (has_error || (i == 0 && has_eof))
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return nullptr;
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str[i] = '\0';
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return str;
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}
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} // namespace __llvm_libc
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