ImmutableStringBuilder.h (2321B)
1 // 2 // Copyright 2018 The ANGLE Project Authors. All rights reserved. 3 // Use of this source code is governed by a BSD-style license that can be 4 // found in the LICENSE file. 5 // 6 // ImmutableStringBuilder.h: Stringstream-like utility for building pool allocated strings where the 7 // maximum length is known in advance. 8 // 9 10 #ifndef COMPILER_TRANSLATOR_IMMUTABLESTRINGBUILDER_H_ 11 #define COMPILER_TRANSLATOR_IMMUTABLESTRINGBUILDER_H_ 12 13 #include "compiler/translator/ImmutableString.h" 14 15 namespace sh 16 { 17 18 class ImmutableStringBuilder 19 { 20 public: 21 ImmutableStringBuilder(size_t maxLength) 22 : mPos(0u), mMaxLength(maxLength), mData(AllocateEmptyPoolCharArray(maxLength)) 23 {} 24 25 ImmutableStringBuilder &operator<<(const ImmutableString &str); 26 27 ImmutableStringBuilder &operator<<(const char *str); 28 29 ImmutableStringBuilder &operator<<(const char &c); 30 31 // This invalidates the ImmutableStringBuilder, so it should only be called once. 32 operator ImmutableString(); 33 34 void appendDecimal(const uint32_t &i); 35 36 template <typename T> 37 void appendHex(T number) 38 { 39 ASSERT(mData != nullptr); 40 ASSERT(mPos + sizeof(T) * 2u <= mMaxLength); 41 int index = static_cast<int>(sizeof(T)) * 2 - 1; 42 // Loop through leading zeroes. 43 while (((number >> (index * 4)) & 0xfu) == 0 && index > 0) 44 { 45 --index; 46 } 47 // Write the rest of the hex digits. 48 while (index >= 0) 49 { 50 char digit = static_cast<char>((number >> (index * 4)) & 0xfu); 51 char digitChar = (digit < 10) ? (digit + '0') : (digit + ('a' - 10)); 52 mData[mPos++] = digitChar; 53 --index; 54 } 55 } 56 57 template <typename T> 58 static constexpr size_t GetHexCharCount() 59 { 60 return sizeof(T) * 2; 61 } 62 63 private: 64 inline static char *AllocateEmptyPoolCharArray(size_t strLength) 65 { 66 size_t requiredSize = strLength + 1u; 67 return static_cast<char *>(GetGlobalPoolAllocator()->allocate(requiredSize)); 68 } 69 70 size_t mPos; 71 size_t mMaxLength; 72 char *mData; 73 }; 74 75 // GLSL ES 3.00.6 section 3.9: the maximum length of an identifier is 1024 characters. 76 constexpr unsigned int kESSLMaxIdentifierLength = 1024u; 77 78 } // namespace sh 79 80 #endif // COMPILER_TRANSLATOR_IMMUTABLESTRINGBUILDER_H_