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open image file using file format signature instead of file extension

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This commit is contained in:
Jinhao 2020-04-18 02:59:12 +08:00
parent 4dcbb50e1f
commit d3e3e59812
1 changed files with 44 additions and 127 deletions
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169
source/paint/image.cpp
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@ -1,7 +1,7 @@
/**
* Paint Image Implementation
* Nana C++ Library(http://www.nanapro.org)
* Copyright(C) 2003-2019 Jinhao(cnjinhao@hotmail.com)
* Copyright(C) 2003-2020 Jinhao(cnjinhao@hotmail.com)
*
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
@ -108,155 +108,72 @@ namespace paint
return *this;
}
std::shared_ptr<image::image_impl_interface> create_image(const fs::path & p)
// Check file type through file format signature
std::shared_ptr<image::image_impl_interface> create_image(const char* buf, std::size_t len)
{
std::shared_ptr<image::image_impl_interface> ptr;
auto ext = p.extension().native();
if (ext.empty())
return ptr;
std::transform(ext.begin(), ext.end(), ext.begin(), [](int ch)
if (buf && len >= 8)
{
if ('A' <= ch && ch <= 'Z')
ch -= ('A' - 'a');
return ch;
});
#if defined(NANA_WINDOWS)
const wchar_t* ext_ico = L".ico";
const wchar_t* ext_png = L".png";
const wchar_t* ext_jpg = L".jpg";
const wchar_t* ext_jpeg = L".jpeg";
#else
const char* ext_ico = ".ico";
const char* ext_png = ".png";
const char* ext_jpg = ".jpg";
const char* ext_jpeg = ".jpeg";
#endif
do
if (std::strncmp("\x00\x00\x01\x00", buf, 4) == 0)
{
if (ext_ico == ext)
{
ptr = std::make_shared<detail::image_ico>();
break;
return std::make_shared<detail::image_ico>();
}
if (ext_png == ext)
else if (std::strncmp(buf, "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A", 8) == 0)
{
#if defined(NANA_ENABLE_PNG)
ptr = std::make_shared<detail::image_png>();
#else
return ptr;
return std::make_shared<detail::image_png>();
#endif
break;
}
if (ext_jpg == ext || ext_jpeg == ext)
else if (std::strncmp("\xFF\xD8\xFF", buf, 3) == 0)
{
#if defined(NANA_ENABLE_JPEG)
ptr = std::make_shared<detail::image_jpeg>();
#else
return ptr;
return std::make_shared<detail::image_jpeg>();
#endif
break;
}
} while (false);
//Check for BMP
if (!ptr)
{
#ifndef NANA_MINGW
std::ifstream ifs(p.c_str(), std::ios::binary);
#else
std::ifstream ifs(to_osmbstr(to_utf8(p.native())).c_str(), std::ios::binary);
#endif
if (ifs)
{
unsigned short meta = 0;
ifs.read(reinterpret_cast<char*>(&meta), 2);
if (*reinterpret_cast<const short*>("BM") == meta)
ptr = std::make_shared<detail::image_bmp>();
else if (*reinterpret_cast<const short*>("MZ") == meta)
ptr = std::make_shared<detail::image_ico_resource>();
}
else if (*reinterpret_cast<const short*>("BM") == *reinterpret_cast<const short*>(buf))
return std::make_shared<detail::image_bmp>();
else if (*reinterpret_cast<const short*>("MZ") == *reinterpret_cast<const short*>(buf))
return std::make_shared<detail::image_ico_resource>();
}
return ptr;
return nullptr;
}
bool image::open(const ::std::string& file)
bool image::open(const ::std::string& img)
{
fs::path path(file);
image_ptr_ = create_image(path);
return (image_ptr_ ? image_ptr_->open(path) : false);
fs::path p(img);
image_ptr_.reset();
std::ifstream file{ p, std::ios::binary };
if (file)
{
char buf[8];
if (file.read(buf, 8).gcount() == 8)
image_ptr_ = create_image(buf, 8);
}
bool image::open(const std::wstring& file)
return (image_ptr_ ? image_ptr_->open(p) : false);
}
bool image::open(const std::wstring& img)
{
fs::path path(file);
image_ptr_ = create_image(path);
return (image_ptr_ ? image_ptr_->open(path) : false);
fs::path p(img);
image_ptr_.reset();
std::ifstream file{ p, std::ios::binary };
if (file)
{
char buf[8];
if (file.read(buf, 8).gcount() == 8)
image_ptr_ = create_image(buf, 8);
}
return (image_ptr_ ? image_ptr_->open(p) : false);
}
bool image::open(const void* data, std::size_t bytes)
{
close();
if (bytes > 2)
{
std::shared_ptr<image::image_impl_interface> ptr;
auto meta = *reinterpret_cast<const unsigned short*>(data);
if (*reinterpret_cast<const short*>("BM") == meta)
ptr = std::make_shared<detail::image_bmp>();
else if (*reinterpret_cast<const short*>("MZ") == meta)
ptr = std::make_shared<detail::image_ico_resource>();
else
{
if (bytes > 8 && (0x474e5089 == *reinterpret_cast<const unsigned*>(data)))
{
#if defined(NANA_ENABLE_PNG)
ptr = std::make_shared<detail::image_png>();
#endif
}
else
{
#if defined(NANA_ENABLE_JPEG)
if ((bytes > 11) && (0xd8ff == *reinterpret_cast<const unsigned short*>(data)))
{
switch(*reinterpret_cast<const unsigned*>(reinterpret_cast<const char*>(data)+6))
{
case 0x4649464A: //JFIF
case 0x66697845: //Exif
ptr = std::make_shared<detail::image_jpeg>();
}
}
else
#endif
if ((!ptr) && (bytes > 40))
{
switch (*reinterpret_cast<const unsigned*>(data))
{
case 40:
case 0x00010000:
if (!ptr && bytes > 40)
ptr = std::make_shared<detail::image_ico>();
}
}
}
}
if (ptr)
{
image_ptr_.swap(ptr);
return image_ptr_->open(data, bytes);
}
}
return false;
image_ptr_ = create_image(static_cast<const char*>(data), bytes);
return (image_ptr_ ? image_ptr_->open(data, bytes) : false);
}