Virtual Hard Disk on File Library

This project is a C++ shared library designed to provide an abstract virtual disk interface for programs that need it.

• Building From Source
• Linking
• API Functions
  • Open Disk
  • Close Disk
  • Read Block
  • Write Block
  • Sync Disk
• Suggestions and Bug Reports

Building From Source

Requirements:

• GNU-compatible Make or Autotools or CMake
• C++ compiler with C++11 support

Make

If using a packaged version, the library can be built and installed by running the following commands:

mkdir build && cd build
../configure
make
make install

CMake

A CMakeLists.txt configuration file is included with the source code. It can be used to generate build scripts and build the application with CMake.

cmake . -Bbuild
cmake --build build --config Release

Optionally, you may set the BUILD_TESTS option to ON in order to build assertion tests. The --config Release flag is optional on unix based systems.

Autotools

If cloning from this repository, the preconfigured distribution files will not be included. To generate them using Autotools, run the following commands in a terminal:

libtoolize 
aclocal
autoconf
automake --add-missing

After running these commands, follow the instructions to build and install using Make.

Linking

To link with this library, simply #include <vhdf.hpp> in your source file and link with the -lvhdf flag, provided that the library is installed in the system PATH.

API Functions

The library provides the following methods in the vhdf namespace:

Open Disk

int openDisk(char* filename, size_t nbytes = 0, bool nosparse = false);

Open the disk file with "filename", or creates it if it does not exist. Returns a descriptor for the opened disk on success or -1 on failure.

Parameters:

• filename The name of the file containing the disk image.
• nbytes If creating the disk, the size of the disk to make. Will be rounded down to the nearest multiple of BLOCK_SIZE.
• nosparce Whether to force writing garbage data to the created file. This will keep the system from treating it as sparse and avoid fragmentation as it grows.

Close Disk

int closeDisk(int disk);

Closes the disk described by "disk". Returns 0 on success, -1 on failure.

Parameters:

• disk The disk descriptor.

Read Block

int readBlock(int disk, size_t blocknr, void* buff);

Reads data from the disk and places it on the provided buffer. Returns 0 on success, or EOF on blocknr out of bounds.

Parameters:

• disk The descriptor for the disk to read from.
• blocknr The number of the block to read.
• buff The buffer in which to place read bytes.

Write Block

int writeBlock(int disk, size_t blocknr, void* buff);

Writes data on the provided buffer to the disk. Returns 0 on success, or EOF on blocknr out of bounds.

Parameters:

• disk The descriptor for the disk to be written.
• blocknr The number of the block to write to.
• buff The buffer containing the data to write.

Sync Disk

void syncDisk();

Forces all outstanding writes to disk. Currently useless as write caching is not implemented.

Suggestions and Bug Reports

If you happen to encounter any bugs while using this library, or have any suggestion of additional features you would like to see implemented, please open an issue on GitHub.