1651f58bfSDiana Picus //===-- runtime/buffer.cpp ------------------------------------------------===// 2f7be2518Speter klausler // 3f7be2518Speter klausler // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4f7be2518Speter klausler // See https://llvm.org/LICENSE.txt for license information. 5f7be2518Speter klausler // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6f7be2518Speter klausler // 7f7be2518Speter klausler //===----------------------------------------------------------------------===// 8f7be2518Speter klausler 9f7be2518Speter klausler #include "buffer.h" 10f7be2518Speter klausler #include <algorithm> 11f7be2518Speter klausler 12f7be2518Speter klausler namespace Fortran::runtime::io { 13*8ebf7411SSlava Zakharin RT_OFFLOAD_API_GROUP_BEGIN 14f7be2518Speter klausler 15f7be2518Speter klausler // Here's a very old trick for shifting circular buffer data cheaply 16f7be2518Speter klausler // without a need for a temporary array. LeftShiftBufferCircularly(char * buffer,std::size_t bytes,std::size_t shift)17f7be2518Speter klauslervoid LeftShiftBufferCircularly( 18f7be2518Speter klausler char *buffer, std::size_t bytes, std::size_t shift) { 19f7be2518Speter klausler // Assume that we start with "efgabcd" and the left shift is 3. 20*8ebf7411SSlava Zakharin RT_DIAG_PUSH 21*8ebf7411SSlava Zakharin RT_DIAG_DISABLE_CALL_HOST_FROM_DEVICE_WARN 22f7be2518Speter klausler std::reverse(buffer, buffer + shift); // "gfeabcd" 23f7be2518Speter klausler std::reverse(buffer, buffer + bytes); // "dcbaefg" 24f7be2518Speter klausler std::reverse(buffer, buffer + bytes - shift); // "abcdefg" 25*8ebf7411SSlava Zakharin RT_DIAG_POP 26f7be2518Speter klausler } 27*8ebf7411SSlava Zakharin 28*8ebf7411SSlava Zakharin RT_OFFLOAD_API_GROUP_END 291f879005STim Keith } // namespace Fortran::runtime::io 30