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//===-- Implementation of fgets -------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "src/stdio/fgets.h"
#include "src/__support/File/file.h"
#include "src/errno/libc_errno.h"
#include <stddef.h>
#include <stdio.h>
namespace __llvm_libc {
LLVM_LIBC_FUNCTION(char *, fgets,
(char *__restrict str, int count,
::FILE *__restrict raw_stream)) {
if (count < 1)
return nullptr;
unsigned char c = '\0';
auto stream = reinterpret_cast<__llvm_libc::File *__restrict>(raw_stream);
stream->lock();
// i is an int because it's frequently compared to count, which is also int.
int i = 0;
for (; i < (count - 1) && c != '\n'; ++i) {
auto result = stream->read_unlocked(&c, 1);
size_t r = result.value;
if (result.has_error())
libc_errno = result.error;
if (r != 1)
break;
str[i] = c;
}
bool has_error = stream->error_unlocked();
bool has_eof = stream->iseof_unlocked();
stream->unlock();
// If the requested read size makes no sense, an error occured, or no bytes
// were read due to an EOF, then return nullptr and don't write the null byte.
if (has_error || (i == 0 && has_eof))
return nullptr;
str[i] = '\0';
return str;
}
} // namespace __llvm_libc
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