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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-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | |
| 9 | #ifndef LLVM_LIBC_SRC_STDIO_SCANF_CORE_STRING_READER_H |
| 10 | #define LLVM_LIBC_SRC_STDIO_SCANF_CORE_STRING_READER_H |
| 11 | |
| 12 | #include "src/__support/macros/attributes.h" // For LIBC_INLINE |
| 13 | #include "src/__support/macros/config.h" |
| 14 | #include "src/stdio/scanf_core/reader.h" |
| 15 | |
| 16 | #include <stddef.h> |
| 17 | |
| 18 | namespace LIBC_NAMESPACE_DECL { |
| 19 | namespace scanf_core { |
| 20 | |
| 21 | class StringReader : public Reader<StringReader> { |
| 22 | const char *buffer; |
| 23 | [[maybe_unused]] size_t buff_len; |
| 24 | size_t buff_cur = 0; |
| 25 | |
| 26 | public: |
| 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 we |
| 38 | // always write the character that was already there. Additionally, the |
| 39 | // 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_core |
| 47 | } // namespace LIBC_NAMESPACE_DECL |
| 48 | |
| 49 | #endif // LLVM_LIBC_SRC_STDIO_SCANF_CORE_STRING_READER_H |
| 50 |
Warning: This file is not a C or C++ file. It does not have highlighting.