png_io_private.hpp

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/*
    Copyright 2005-2007 Adobe Systems Incorporated
   
    Use, modification and distribution are subject to the Boost Software License,
    Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
    http://www.boost.org/LICENSE_1_0.txt).

    See http://stlab.adobe.com/gil for most recent version including documentation.
*/
/*************************************************************************************************/

#ifndef GIL_PNG_IO_PRIVATE_H
#define GIL_PNG_IO_PRIVATE_H

/// \file
/// \brief  Internal support for reading and writing PNG files
/// \author Hailin Jin and Lubomir Bourdev \n
///         Adobe Systems Incorporated
/// \date   2005-2007 \n Last updated August 14, 2007

#include <algorithm>
#include <vector>
#include <boost/static_assert.hpp>
#include "../../gil_all.hpp"
#include "io_error.hpp"

namespace boost { namespace gil {

namespace detail {

static const std::size_t PNG_BYTES_TO_CHECK = 4;

// lbourdev: These can be greatly simplified, for example:
template <typename Cs> struct png_color_type {BOOST_STATIC_CONSTANT(int,color_type=0);};
template<> struct png_color_type<gray_t> { BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_GRAY); };
template<> struct png_color_type<rgb_t>  { BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_RGB); };
template<> struct png_color_type<rgba_t> { BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_RGBA); };

template <typename Channel,typename ColorSpace> struct png_is_supported {BOOST_STATIC_CONSTANT(bool,value=false);};
template <> struct png_is_supported<bits8,gray_t>  {BOOST_STATIC_CONSTANT(bool,value=true);};
template <> struct png_is_supported<bits8,rgb_t>   {BOOST_STATIC_CONSTANT(bool,value=true);};
template <> struct png_is_supported<bits8,rgba_t>  {BOOST_STATIC_CONSTANT(bool,value=true);};
template <> struct png_is_supported<bits16,gray_t> {BOOST_STATIC_CONSTANT(bool,value=true);};
template <> struct png_is_supported<bits16,rgb_t>  {BOOST_STATIC_CONSTANT(bool,value=true);};
template <> struct png_is_supported<bits16,rgba_t> {BOOST_STATIC_CONSTANT(bool,value=true);};

template <typename Channel> struct png_bit_depth {BOOST_STATIC_CONSTANT(int,bit_depth=sizeof(Channel)*8);};

template <typename Channel,typename ColorSpace>
struct png_read_support_private {
    BOOST_STATIC_CONSTANT(bool,is_supported=false);
    BOOST_STATIC_CONSTANT(int,bit_depth=0);
    BOOST_STATIC_CONSTANT(int,color_type=0);
};
template <>
struct png_read_support_private<bits8,gray_t> {
    BOOST_STATIC_CONSTANT(bool,is_supported=true);
    BOOST_STATIC_CONSTANT(int,bit_depth=8);
    BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_GRAY);
};
template <>
struct png_read_support_private<bits8,rgb_t> {
    BOOST_STATIC_CONSTANT(bool,is_supported=true);
    BOOST_STATIC_CONSTANT(int,bit_depth=8);
    BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_RGB);
};
template <>
struct png_read_support_private<bits8,rgba_t> {
    BOOST_STATIC_CONSTANT(bool,is_supported=true);
    BOOST_STATIC_CONSTANT(int,bit_depth=8);
    BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_RGBA);
};
template <>
struct png_read_support_private<bits16,gray_t> {
    BOOST_STATIC_CONSTANT(bool,is_supported=true);
    BOOST_STATIC_CONSTANT(int,bit_depth=16);
    BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_GRAY);
};
template <>
struct png_read_support_private<bits16,rgb_t> {
    BOOST_STATIC_CONSTANT(bool,is_supported=true);
    BOOST_STATIC_CONSTANT(int,bit_depth=16);
    BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_RGB);
};
template <>
struct png_read_support_private<bits16,rgba_t> {
    BOOST_STATIC_CONSTANT(bool,is_supported=true);
    BOOST_STATIC_CONSTANT(int,bit_depth=16);
    BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_RGBA);
};

template <typename Channel,typename ColorSpace>
struct png_write_support_private {
    BOOST_STATIC_CONSTANT(bool,is_supported=false);
    BOOST_STATIC_CONSTANT(int,bit_depth=0);
    BOOST_STATIC_CONSTANT(int,color_type=0);
};
template <>
struct png_write_support_private<bits8,gray_t> {
    BOOST_STATIC_CONSTANT(bool,is_supported=true);
    BOOST_STATIC_CONSTANT(int,bit_depth=8);
    BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_GRAY);
};
template <>
struct png_write_support_private<bits8,rgb_t> {
    BOOST_STATIC_CONSTANT(bool,is_supported=true);
    BOOST_STATIC_CONSTANT(int,bit_depth=8);
    BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_RGB);
};
template <>
struct png_write_support_private<bits8,rgba_t> {
    BOOST_STATIC_CONSTANT(bool,is_supported=true);
    BOOST_STATIC_CONSTANT(int,bit_depth=8);
    BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_RGBA);
};
template <>
struct png_write_support_private<bits16,gray_t> {
    BOOST_STATIC_CONSTANT(bool,is_supported=true);
    BOOST_STATIC_CONSTANT(int,bit_depth=16);
    BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_GRAY);
};
template <>
struct png_write_support_private<bits16,rgb_t> {
    BOOST_STATIC_CONSTANT(bool,is_supported=true);
    BOOST_STATIC_CONSTANT(int,bit_depth=16);
    BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_RGB);
};
template <>
struct png_write_support_private<bits16,rgba_t> {
    BOOST_STATIC_CONSTANT(bool,is_supported=true);
    BOOST_STATIC_CONSTANT(int,bit_depth=16);
    BOOST_STATIC_CONSTANT(int,color_type=PNG_COLOR_TYPE_RGBA);
};

class png_reader : public file_mgr {
protected:
    png_structp _png_ptr;
    png_infop _info_ptr;

    void init() {
        char buf[PNG_BYTES_TO_CHECK];
        // read in some of the signature bytes
        io_error_if(fread(buf, 1, PNG_BYTES_TO_CHECK, get()) != detail::PNG_BYTES_TO_CHECK,
                    "png_check_validity: fail to read file");
        // compare the first PNG_BYTES_TO_CHECK bytes of the signature.
        io_error_if(png_sig_cmp((png_bytep)buf, (png_size_t)0, detail::PNG_BYTES_TO_CHECK)!=0,
                    "png_check_validity: invalid png file");

        _png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,NULL,NULL,NULL);
        io_error_if(_png_ptr==NULL,"png_get_file_size: fail to call png_create_write_struct()");
        // allocate/initialize the image information data
        _info_ptr = png_create_info_struct(_png_ptr);
        if (_info_ptr == NULL) {
            png_destroy_read_struct(&_png_ptr,png_infopp_NULL,png_infopp_NULL);
            io_error("png_get_file_size: fail to call png_create_info_struct()");
        }
        if (setjmp(png_jmpbuf(_png_ptr))) {
            //free all of the memory associated with the png_ptr and info_ptr
            png_destroy_read_struct(&_png_ptr, &_info_ptr, png_infopp_NULL);
            io_error("png_get_file_size: fail to call setjmp()");
        }
        png_init_io(_png_ptr, get());
        png_set_sig_bytes(_png_ptr,PNG_BYTES_TO_CHECK);
        png_read_info(_png_ptr, _info_ptr);
        if (little_endian() && png_get_bit_depth(_png_ptr,_info_ptr)>8)
            png_set_swap(_png_ptr);
    }
public:
    png_reader(FILE* file          ) : file_mgr(file)           { init(); }
    png_reader(const char* filename) : file_mgr(filename, "rb") { init(); }

    ~png_reader() {
        png_destroy_read_struct(&_png_ptr,&_info_ptr,png_infopp_NULL);
    }
    point2<std::ptrdiff_t> get_dimensions() {
        return point2<std::ptrdiff_t>(png_get_image_width(_png_ptr,_info_ptr),
                                      png_get_image_height(_png_ptr,_info_ptr));
    }
    template <typename View>
    void apply(const View& view) {