1a1be5d69SJoseph Huber //===-- Implementation of fgets -------------------------------------------===// 2a1be5d69SJoseph Huber // 3a1be5d69SJoseph Huber // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4a1be5d69SJoseph Huber // See https://llvm.org/LICENSE.txt for license information. 5a1be5d69SJoseph Huber // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6a1be5d69SJoseph Huber // 7a1be5d69SJoseph Huber //===----------------------------------------------------------------------===// 8a1be5d69SJoseph Huber 9a1be5d69SJoseph Huber #include "src/stdio/fgets.h" 10a1be5d69SJoseph Huber #include "src/__support/File/file.h" 11a1be5d69SJoseph Huber 125aed6d67SMichael Jones #include "hdr/types/FILE.h" 13*5ff3ff33SPetr Hosek #include "src/__support/macros/config.h" 14a1be5d69SJoseph Huber #include "src/errno/libc_errno.h" 15a1be5d69SJoseph Huber #include <stddef.h> 16a1be5d69SJoseph Huber 17*5ff3ff33SPetr Hosek namespace LIBC_NAMESPACE_DECL { 18a1be5d69SJoseph Huber 19a1be5d69SJoseph Huber LLVM_LIBC_FUNCTION(char *, fgets, 20a1be5d69SJoseph Huber (char *__restrict str, int count, 21a1be5d69SJoseph Huber ::FILE *__restrict raw_stream)) { 22a1be5d69SJoseph Huber if (count < 1) 23a1be5d69SJoseph Huber return nullptr; 24a1be5d69SJoseph Huber 25a1be5d69SJoseph Huber unsigned char c = '\0'; 26b6bc9d72SGuillaume Chatelet auto stream = reinterpret_cast<LIBC_NAMESPACE::File *__restrict>(raw_stream); 27a1be5d69SJoseph Huber stream->lock(); 28a1be5d69SJoseph Huber 29a1be5d69SJoseph Huber // i is an int because it's frequently compared to count, which is also int. 30a1be5d69SJoseph Huber int i = 0; 31a1be5d69SJoseph Huber 32a1be5d69SJoseph Huber for (; i < (count - 1) && c != '\n'; ++i) { 33a1be5d69SJoseph Huber auto result = stream->read_unlocked(&c, 1); 34a1be5d69SJoseph Huber size_t r = result.value; 35a1be5d69SJoseph Huber if (result.has_error()) 36a1be5d69SJoseph Huber libc_errno = result.error; 37a1be5d69SJoseph Huber 38a1be5d69SJoseph Huber if (r != 1) 39a1be5d69SJoseph Huber break; 40a1be5d69SJoseph Huber str[i] = c; 41a1be5d69SJoseph Huber } 42a1be5d69SJoseph Huber 43a1be5d69SJoseph Huber bool has_error = stream->error_unlocked(); 44a1be5d69SJoseph Huber bool has_eof = stream->iseof_unlocked(); 45a1be5d69SJoseph Huber stream->unlock(); 46a1be5d69SJoseph Huber 47a1be5d69SJoseph Huber // If the requested read size makes no sense, an error occured, or no bytes 48a1be5d69SJoseph Huber // were read due to an EOF, then return nullptr and don't write the null byte. 49a1be5d69SJoseph Huber if (has_error || (i == 0 && has_eof)) 50a1be5d69SJoseph Huber return nullptr; 51a1be5d69SJoseph Huber 52a1be5d69SJoseph Huber str[i] = '\0'; 53a1be5d69SJoseph Huber return str; 54a1be5d69SJoseph Huber } 55a1be5d69SJoseph Huber 56*5ff3ff33SPetr Hosek } // namespace LIBC_NAMESPACE_DECL 57