Home | History | Annotate | Download | only in utils 
      1 // Copyright 2014 The Android Open Source Project
      2 //
      3 // This software is licensed under the terms of the GNU General Public
      4 // License version 2, as published by the Free Software Foundation, and
      5 // may be copied, distributed, and modified under those terms.
      6 //
      7 // This program is distributed in the hope that it will be useful,
      8 // but WITHOUT ANY WARRANTY; without even the implied warranty of
      9 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     10 // GNU General Public License for more details.
     11 
     12 #ifndef ANDROID_UTILS_FILE_UTILS_H
     13 #define ANDROID_UTILS_FILE_UTILS_H
     14 
     15 #include "android/utils/compiler.h"
     16 
     17 #include <stdbool.h>
     18 #include <stddef.h>
     19 #include <stdint.h>
     20 
     21 ANDROID_BEGIN_HEADER
     22 
     23 // A simple structure used to own a buffer of heap-allocated memory that
     24 // typically comes from a file.
     25 // |data| is the address of the corresponding data in memory.
     26 // |size| is the size of the data in bytes.
     27 // |flags| is used internally, do not use it.
     28 // Note that |data| will always be NULL if |size| is 0.
     29 typedef struct {
     30     uint8_t* data;
     31     size_t size;
     32     // private
     33     size_t flags;
     34 } FileData;
     35 
     36 // Initializer value for a FileData instance.
     37 // Its important that this is all zeroes.
     38 #define FILE_DATA_INIT  { NULL, 0, 0 }
     39 
     40 // Return true iff a |fileData| is empty.
     41 static inline bool fileData_isEmpty(const FileData* fileData) {
     42     return fileData->size == 0;
     43 }
     44 
     45 // Returns true iff |fileData| is valid. Used for unit-testing.
     46 bool fileData_isValid(const FileData* fileData);
     47 
     48 // Initialize a FileData value to the empty value.
     49 void fileData_initEmpty(FileData* fileData);
     50 
     51 // Initialize a FileData value by reading the content of a given file
     52 // at |filePath|. On success, return 0 and initializes |fileData| properly.
     53 // On failure, return -errno code, and set |fileData| to FILE_DATA_INIT.
     54 int fileData_initFromFile(FileData* fileData, const char* filePath);
     55 
     56 // Initialize a FileData by copying a memory buffer.
     57 // |fileData| is the address of the FileData value to initialize.
     58 // |buffer| is the address of the input buffer that will be copied
     59 // into the FileData.
     60 // |bufferLen| is the buffer length in bytes.
     61 // Return 0 on success, -errno code on failure.
     62 int fileData_initFromMemory(FileData* fileData,
     63                             const void* buffer,
     64                             size_t bufferLen);
     65 
     66 // Copy a FileData value into another one. This copies the contents in
     67 // the heap. On success return 0, on failure -errno code.
     68 int fileData_initFrom(FileData* fileData, const FileData* other);
     69 
     70 // Swap two FileData values.
     71 void fileData_swap(FileData* fileData, FileData* other);
     72 
     73 // Finalize a FileData value. This releases the corresponding memory.
     74 void fileData_done(FileData* fileData);
     75 
     76 ANDROID_END_HEADER
     77 
     78 #endif  // ANDROID_UTILS_FILE_UTILS_H
     79