Provided by: mrc_1.3.15-2_amd64 
NAME
mrc - A resource compiler
SYNOPSIS
mrc [-o|--output outputfile]
[--root arg]
[--resource-prefix arg]
[--elf-machine arg]
[--elf-class arg]
[--elf-data arg]
[--elf-abi arg]
[--elf-flags arg]
file1 [file2...]
mrc [-h|--help]
mrc [-v|--version]
mrc [--header] > mrsrc.h
#include "mrsrc.h"
void foo()
{
mrsrc::rsrc data("/alerts/text.txt");
if (data) {
mrsrc::istream is(data);
...
}
}
DESCRIPTION
Many applications come with supplementary data. This data is usually stored on disk as regular files. The
disadvantage of this procedure is that an application cannot simply be copied to another location or
computer and expected to function properly.
Resources are a way to overcome this problem by including all data inside the executable file. The mrc
resource compiler can create object files containing both the data and an index. This data can then be
accessed from within an application using C++ classes.
OPTIONS
[-o|--output] file
Specify the output file, the resulting file will be an object file you can link together with the
rest of your object files into an executable file.
--root The resources are accessed using a path. You can specify the root part of the path using this
parameter.
--resource-prefix name
Use this option to specify another name for the global variables in the data section.
--elf-machine arg
By default mrc assumes you want to create a resource file for the machine it runs on. But using
this option you can create files for other architectures, useful when cross compiling.
The machine flag is used to specify the value of the e_machine field in the ELF header.
--elf-class number
The ELF class to use, should be either 1 for 32-bit objects or 2 for 64-bit objects.
--elf-data number
The ELF data endianness to use, should be either 1 for little-endian (=LSB) objects or 2 for big-
endian (=MSB) objects.
--elf-abi number
The ELF OS ABI flag to use, the exact value for this flag should be looked up in elf.h. Default is
to use the value for the current architecture. (Value of 3 is for Linux, 9 is for FreeBSD).
--elf-flags number
A value to store in the e_flags field of the ELF header. This can contain the EABI version for ARM
e.g.
--coff type
When this option is specified, a COFF file is created for use on Windows. The argument type
should be one of x64, x86 or arm64.
--header
This option will print a mrsrc.h file to stdout which you can write to disk and use to access
resources. Use with the --output option to write to a file instead.
[-v|--verbose]
Print debug output, useful to track where all data ends up in the resource.
--version
Print version number and exit.
[-h|--help]
Print simple help summary and exit.
file [file...]
One or more files to include in the resource file. Directory names can be used as well. All
regular files end up in the root of the resource tree, files found in directories end up in
directies in the resource tree. The following rules apply:
Regular files are added in the root of the resource tree using their proper file name.
If the file name refers to a directory, the directory is traversed recursively and all files are
added. If the file name ends with a forward slash (/) files are added to the root. If the file
does not end with a slash, the name of the directory will be placed in the root and all contained
files will be placed beneath this.
EXAMPLES
Here's a list of usage cases.
mrc -o x.o my-resource.txt my-image.png
Will create a resource file containing two resources accessible using the path "/my-resource.txt"
and "/my-image.png" respectively.
mrc -o x.o img/my-image.png
Will create a resource file containing a single resource accessible using the path "/my-
image.png".
mrc -o x.o img/
Assuming there are two images in the directory img called my-image-1.png and my-image-2.png, the
resource file will contain them both accessible under the name "/my-image-1.png" and "/my-
image-1.png".
mrc -o x.o img Same as the previous, but note there's no trailing slash, the resource file will
contain both images but they are now accessible under the name "/img/my-image-1.png" and "/img/my-
image-1.png".
Use the verbose flag (--verbose) to track what ends up where.
DETAILS
The way this works is that mrc first collects all data from the files specified, including the files
found in specified directories. An simple index is created to allow hierarchical access to the data.
The data is then flattened into three data structures and these are written to the .data section of the
object file. The three data blobs are then made available as globals in your application with the names
gResourceIndex, gResourceName and gResourceData. You can specify the prefix part of this variable with
the -fB--resource-prefix option.
The index entries have the following format:
struct rsrc_imp
{
unsigned int m_next; // index of the next sibling entry
unsigned int m_child; // index of the first child entry
unsigned int m_name; // offset of the name for this entry
unsigned int m_size; // data size for this entry
unsigned int m_data; // offset of the data for this entry
};
The classes in the mrsrc.h file are contained in the namespace mrsrc. The available classes are
mrsrc::rsrc
This is the basic class to access data. It has a constructor that takes a path to a resource. Data
can be accessed using the data method and the size of the data is available via the size method.
If the resource was not found, data will return nullptr and size will return zero. You can also
use operator bool to check for valid data.
mrsrc::streambuf
This class is derived from std::streambuf. It can take both a mrsrc::rsrc or a path as constructor
parameter.
mrsrc::istream
This class is derived from std::istream. It can take both a mrsrc::rsrc or a path as constructor
parameter.
BUGS
This application can only generate ELF formatted object files on machines that have an <elf.h> header
file installed.
Only a single resource entry can be generated and there's no way to merge or manipulate resource files
yet.
version 1.3.6 2022-12-03 mrc(1)