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1//===-- Reader definition for scanf -----------------------------*- C++ -*-===//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#ifndef LLVM_LIBC_SRC_STDIO_SCANF_CORE_STRING_READER_H10#define LLVM_LIBC_SRC_STDIO_SCANF_CORE_STRING_READER_H11 12#include "src/__support/macros/attributes.h" // For LIBC_INLINE13#include "src/__support/macros/config.h"14#include "src/stdio/scanf_core/reader.h"15 16#include <stddef.h>17 18namespace LIBC_NAMESPACE_DECL {19namespace scanf_core {20 21class StringReader : public Reader<StringReader> {22 const char *buffer;23 [[maybe_unused]] size_t buff_len;24 size_t buff_cur = 0;25 26public:27 LIBC_INLINE StringReader(const char *buffer, size_t buff_len)28 : buffer(buffer), buff_len(buff_len) {}29 30 LIBC_INLINE char getc() {31 char output = buffer[buff_cur];32 ++buff_cur;33 return output;34 }35 LIBC_INLINE void ungetc(int) {36 if (buff_cur > 0) {37 // While technically c should be written back to the buffer, in scanf we38 // always write the character that was already there. Additionally, the39 // buffer is most likely to contain a string that isn't part of a file,40 // which may not be writable.41 --buff_cur;42 }43 }44};45 46} // namespace scanf_core47} // namespace LIBC_NAMESPACE_DECL48 49#endif // LLVM_LIBC_SRC_STDIO_SCANF_CORE_STRING_READER_H50