1 //===- LEB128.cpp - LEB128 utility functions implementation -----*- 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 // This file implements some utility functions for encoding SLEB128 and 10 // ULEB128 values. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Support/LEB128.h" 15 16 namespace llvm { 17 18 /// Utility function to get the size of the ULEB128-encoded value. getULEB128Size(uint64_t Value)19 unsigned getULEB128Size(uint64_t Value) { 20 unsigned Size = 0; 21 do { 22 Value >>= 7; 23 Size += sizeof(int8_t); 24 } while (Value); 25 return Size; 26 } 27 28 /// Utility function to get the size of the SLEB128-encoded value. getSLEB128Size(int64_t Value)29 unsigned getSLEB128Size(int64_t Value) { 30 unsigned Size = 0; 31 int Sign = Value >> (8 * sizeof(Value) - 1); 32 bool IsMore; 33 34 do { 35 unsigned Byte = Value & 0x7f; 36 Value >>= 7; 37 IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0; 38 Size += sizeof(int8_t); 39 } while (IsMore); 40 return Size; 41 } 42 43 } // namespace llvm 44