Microsoft Windows uses specific file format to store applications icons - ICO. This is a container that contains one or more image files (effectively, DIB parts of BMP files or full PNG files are contained inside).
This page hosts a formal specification of Microsoft Windows icon file using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for C++98/STL generated by Kaitai Struct depends on the C++/STL runtime library. You have to install it before you can parse data.
For C++, the easiest way is to clone the runtime library sources and build them along with your project.
Using Kaitai Struct in C++/STL usually consists of 3 steps.
std::istream). One can open local file for that, or use existing std::string or char* buffer.
#include <fstream>
std::ifstream is("path/to/local/file.ico", std::ifstream::binary);
#include <sstream>
std::istringstream is(str);
#include <sstream>
const char buf[] = { ... };
std::string str(buf, sizeof buf);
std::istringstream is(str);
#include "kaitai/kaitaistream.h"
kaitai::kstream ks(&is);
ico_t data(&ks);
After that, one can get various attributes from the structure by invoking getter methods like:
data.num_images() // => Number of images contained in this file
#ifndef ICO_H_
#define ICO_H_
// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
#include "kaitai/kaitaistruct.h"
#include <stdint.h>
#include <vector>
#if KAITAI_STRUCT_VERSION < 9000L
#error "Incompatible Kaitai Struct C++/STL API: version 0.9 or later is required"
#endif
/**
* Microsoft Windows uses specific file format to store applications
* icons - ICO. This is a container that contains one or more image
* files (effectively, DIB parts of BMP files or full PNG files are
* contained inside).
* \sa https://learn.microsoft.com/en-us/previous-versions/ms997538(v=msdn.10) Source
*/
class ico_t : public kaitai::kstruct {
public:
class icon_dir_entry_t;
ico_t(kaitai::kstream* p__io, kaitai::kstruct* p__parent = 0, ico_t* p__root = 0);
private:
void _read();
void _clean_up();
public:
~ico_t();
class icon_dir_entry_t : public kaitai::kstruct {
public:
icon_dir_entry_t(kaitai::kstream* p__io, ico_t* p__parent = 0, ico_t* p__root = 0);
private:
void _read();
void _clean_up();
public:
~icon_dir_entry_t();
private:
bool f_img;
std::string m_img;
public:
/**
* Raw image data. Use `is_png` to determine whether this is an
* embedded PNG file (true) or a DIB bitmap (false) and call a
* relevant parser, if needed to parse image data further.
*/
std::string img();
private:
bool f_png_header;
std::string m_png_header;
public:
/**
* Pre-reads first 8 bytes of the image to determine if it's an
* embedded PNG file.
*/
std::string png_header();
private:
bool f_is_png;
bool m_is_png;
public:
/**
* True if this image is in PNG format.
*/
bool is_png();
private:
uint8_t m_width;
uint8_t m_height;
uint8_t m_num_colors;
std::string m_reserved;
uint16_t m_num_planes;
uint16_t m_bpp;
uint32_t m_len_img;
uint32_t m_ofs_img;
ico_t* m__root;
ico_t* m__parent;
public:
/**
* Width of image, px
*/
uint8_t width() const { return m_width; }
/**
* Height of image, px
*/
uint8_t height() const { return m_height; }
/**
* Number of colors in palette of the image or 0 if image has
* no palette (i.e. RGB, RGBA, etc)
*/
uint8_t num_colors() const { return m_num_colors; }
std::string reserved() const { return m_reserved; }
/**
* Number of color planes
*/
uint16_t num_planes() const { return m_num_planes; }
/**
* Bits per pixel in the image
*/
uint16_t bpp() const { return m_bpp; }
/**
* Size of the image data
*/
uint32_t len_img() const { return m_len_img; }
/**
* Absolute offset of the image data start in the file
*/
uint32_t ofs_img() const { return m_ofs_img; }
ico_t* _root() const { return m__root; }
ico_t* _parent() const { return m__parent; }
};
private:
std::string m_magic;
uint16_t m_num_images;
std::vector<icon_dir_entry_t*>* m_images;
ico_t* m__root;
kaitai::kstruct* m__parent;
public:
std::string magic() const { return m_magic; }
/**
* Number of images contained in this file
*/
uint16_t num_images() const { return m_num_images; }
std::vector<icon_dir_entry_t*>* images() const { return m_images; }
ico_t* _root() const { return m__root; }
kaitai::kstruct* _parent() const { return m__parent; }
};
#endif // ICO_H_
// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
#include "ico.h"
#include "kaitai/exceptions.h"
ico_t::ico_t(kaitai::kstream* p__io, kaitai::kstruct* p__parent, ico_t* p__root) : kaitai::kstruct(p__io) {
m__parent = p__parent;
m__root = this;
m_images = 0;
try {
_read();
} catch(...) {
_clean_up();
throw;
}
}
void ico_t::_read() {
m_magic = m__io->read_bytes(4);
if (!(magic() == std::string("\x00\x00\x01\x00", 4))) {
throw kaitai::validation_not_equal_error<std::string>(std::string("\x00\x00\x01\x00", 4), magic(), _io(), std::string("/seq/0"));
}
m_num_images = m__io->read_u2le();
m_images = new std::vector<icon_dir_entry_t*>();
const int l_images = num_images();
for (int i = 0; i < l_images; i++) {
m_images->push_back(new icon_dir_entry_t(m__io, this, m__root));
}
}
ico_t::~ico_t() {
_clean_up();
}
void ico_t::_clean_up() {
if (m_images) {
for (std::vector<icon_dir_entry_t*>::iterator it = m_images->begin(); it != m_images->end(); ++it) {
delete *it;
}
delete m_images; m_images = 0;
}
}
ico_t::icon_dir_entry_t::icon_dir_entry_t(kaitai::kstream* p__io, ico_t* p__parent, ico_t* p__root) : kaitai::kstruct(p__io) {
m__parent = p__parent;
m__root = p__root;
f_img = false;
f_png_header = false;
f_is_png = false;
try {
_read();
} catch(...) {
_clean_up();
throw;
}
}
void ico_t::icon_dir_entry_t::_read() {
m_width = m__io->read_u1();
m_height = m__io->read_u1();
m_num_colors = m__io->read_u1();
m_reserved = m__io->read_bytes(1);
if (!(reserved() == std::string("\x00", 1))) {
throw kaitai::validation_not_equal_error<std::string>(std::string("\x00", 1), reserved(), _io(), std::string("/types/icon_dir_entry/seq/3"));
}
m_num_planes = m__io->read_u2le();
m_bpp = m__io->read_u2le();
m_len_img = m__io->read_u4le();
m_ofs_img = m__io->read_u4le();
}
ico_t::icon_dir_entry_t::~icon_dir_entry_t() {
_clean_up();
}
void ico_t::icon_dir_entry_t::_clean_up() {
if (f_img) {
}
if (f_png_header) {
}
}
std::string ico_t::icon_dir_entry_t::img() {
if (f_img)
return m_img;
std::streampos _pos = m__io->pos();
m__io->seek(ofs_img());
m_img = m__io->read_bytes(len_img());
m__io->seek(_pos);
f_img = true;
return m_img;
}
std::string ico_t::icon_dir_entry_t::png_header() {
if (f_png_header)
return m_png_header;
std::streampos _pos = m__io->pos();
m__io->seek(ofs_img());
m_png_header = m__io->read_bytes(8);
m__io->seek(_pos);
f_png_header = true;
return m_png_header;
}
bool ico_t::icon_dir_entry_t::is_png() {
if (f_is_png)
return m_is_png;
m_is_png = png_header() == std::string("\x89\x50\x4E\x47\x0D\x0A\x1A\x0A", 8);
f_is_png = true;
return m_is_png;
}