1 //===-- runtime/buffer.cpp ------------------------------------------------===// 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 #include "buffer.h" 10 #include <algorithm> 11 12 namespace Fortran::runtime::io { 13 RT_OFFLOAD_API_GROUP_BEGIN 14 15 // Here's a very old trick for shifting circular buffer data cheaply 16 // without a need for a temporary array. LeftShiftBufferCircularly(char * buffer,std::size_t bytes,std::size_t shift)17void LeftShiftBufferCircularly( 18 char *buffer, std::size_t bytes, std::size_t shift) { 19 // Assume that we start with "efgabcd" and the left shift is 3. 20 RT_DIAG_PUSH 21 RT_DIAG_DISABLE_CALL_HOST_FROM_DEVICE_WARN 22 std::reverse(buffer, buffer + shift); // "gfeabcd" 23 std::reverse(buffer, buffer + bytes); // "dcbaefg" 24 std::reverse(buffer, buffer + bytes - shift); // "abcdefg" 25 RT_DIAG_POP 26 } 27 28 RT_OFFLOAD_API_GROUP_END 29 } // namespace Fortran::runtime::io 30