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//===-- Reader definition for scanf -----------------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC_STDIO_SCANF_CORE_STRING_READER_H
#define LLVM_LIBC_SRC_STDIO_SCANF_CORE_STRING_READER_H
#include "src/__support/macros/attributes.h" // For LIBC_INLINE
#include "src/__support/macros/config.h"
#include "src/stdio/scanf_core/reader.h"
#include <stddef.h>
namespace LIBC_NAMESPACE_DECL {
namespace scanf_core {
class StringReader : public Reader<StringReader> {
const char *buffer;
[[maybe_unused]] size_t buff_len;
size_t buff_cur = 0;
public:
LIBC_INLINE StringReader(const char *buffer, size_t buff_len)
: buffer(buffer), buff_len(buff_len) {}
LIBC_INLINE char getc() {
char output = buffer[buff_cur];
++buff_cur;
return output;
}
LIBC_INLINE void ungetc(int) {
if (buff_cur > 0) {
// While technically c should be written back to the buffer, in scanf we
// always write the character that was already there. Additionally, the
// buffer is most likely to contain a string that isn't part of a file,
// which may not be writable.
--buff_cur;
}
}
};
} // namespace scanf_core
} // namespace LIBC_NAMESPACE_DECL
#endif // LLVM_LIBC_SRC_STDIO_SCANF_CORE_STRING_READER_H
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