1 // Copyright 2015 The Chromium OS Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef CHROMIUMOS_WIDE_PROFILING_DATA_READER_H_ 6 #define CHROMIUMOS_WIDE_PROFILING_DATA_READER_H_ 7 8 #include <stddef.h> 9 #include <stdint.h> 10 11 #include "binary_data_utils.h" 12 #include "compat/string.h" 13 14 namespace quipper { 15 16 class DataReader { 17 public: 18 DataReader() : is_cross_endian_(false) {} 19 virtual ~DataReader() {} 20 21 // Moves the data read pointer to |offset| bytes from the beginning of the 22 // data. 23 virtual void SeekSet(size_t offset) = 0; 24 25 // Returns the position of the data read pointer, in bytes from the beginning 26 // of the data. 27 virtual size_t Tell() const = 0; 28 29 virtual size_t size() const { return size_; } 30 31 // Reads raw data into |dest|. Returns true if it managed to read |size| 32 // bytes. 33 virtual bool ReadData(const size_t size, void* dest) = 0; 34 35 // Reads raw data into a string. 36 virtual bool ReadDataString(const size_t size, string* dest); 37 38 // Like ReadData(), but prints an error if it doesn't read all |size| bytes. 39 virtual bool ReadDataValue(const size_t size, const string& value_name, 40 void* dest); 41 42 // Read integers with endian swapping. 43 bool ReadUint16(uint16_t* value) { return ReadIntValue(value); } 44 bool ReadUint32(uint32_t* value) { return ReadIntValue(value); } 45 bool ReadUint64(uint64_t* value) { return ReadIntValue(value); } 46 47 // Read a string. Returns true if it managed to read |size| bytes (excluding 48 // null terminator). The actual string may be shorter than the number of bytes 49 // requested. 50 virtual bool ReadString(const size_t size, string* str) = 0; 51 52 // Reads a string from data into |dest| at the current offset. The string in 53 // data is prefixed with a 32-bit size field. The size() of |*dest| after the 54 // read will be the null-terminated string length of the underlying string 55 // data, and not necessarily the same as the size field in the data. 56 bool ReadStringWithSizeFromData(string* dest); 57 58 bool is_cross_endian() const { return is_cross_endian_; } 59 60 void set_is_cross_endian(bool value) { is_cross_endian_ = value; } 61 62 protected: 63 // Size of the data source. 64 size_t size_; 65 66 private: 67 // Like ReadData(), but used specifically to read integers. Will swap byte 68 // order if necessary. 69 // For type-safety this one private and let public member functions call it. 70 template <typename T> 71 bool ReadIntValue(T* dest) { 72 if (!ReadData(sizeof(T), dest)) return false; 73 *dest = MaybeSwap(*dest, is_cross_endian_); 74 return true; 75 } 76 77 // For cross-endian data reading. 78 bool is_cross_endian_; 79 }; 80 81 } // namespace quipper 82 83 #endif // CHROMIUMOS_WIDE_PROFILING_DATA_READER_H_ 84
