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//===-- runtime/buffer.cpp ------------------------------------------------===//
//
// 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 "buffer.h"
#include <algorithm>
namespace Fortran::runtime::io {
// Here's a very old trick for shifting circular buffer data cheaply
// without a need for a temporary array.
void LeftShiftBufferCircularly(
char *buffer, std::size_t bytes, std::size_t shift) {
// Assume that we start with "efgabcd" and the left shift is 3.
std::reverse(buffer, buffer + shift); // "gfeabcd"
std::reverse(buffer, buffer + bytes); // "dcbaefg"
std::reverse(buffer, buffer + bytes - shift); // "abcdefg"
}
} // namespace Fortran::runtime::io
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