1 //===- LEB128.cpp - LEB128 utility functions implementation -----*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements some utility functions for encoding SLEB128 and 11 // ULEB128 values. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "llvm/Support/LEB128.h" 16 17 namespace llvm { 18 19 /// Utility function to get the size of the ULEB128-encoded value. getULEB128Size(uint64_t Value)20unsigned getULEB128Size(uint64_t Value) { 21 unsigned Size = 0; 22 do { 23 Value >>= 7; 24 Size += sizeof(int8_t); 25 } while (Value); 26 return Size; 27 } 28 29 /// Utility function to get the size of the SLEB128-encoded value. getSLEB128Size(int64_t Value)30unsigned getSLEB128Size(int64_t Value) { 31 unsigned Size = 0; 32 int Sign = Value >> (8 * sizeof(Value) - 1); 33 bool IsMore; 34 35 do { 36 unsigned Byte = Value & 0x7f; 37 Value >>= 7; 38 IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0; 39 Size += sizeof(int8_t); 40 } while (IsMore); 41 return Size; 42 } 43 44 } // namespace llvm 45