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Add support for loading Png data directly from a memory buffer. (#6527)

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* Add support for loading Png data directly from a memory buffer.

Signed-off-by: Mike Balfour <82224783+mbalfour-amzn@users.noreply.github.com>
(cherry picked from commit 6193dcf603d3c16ee193e1e6dc868bd6d04f89bc)

* Addressed PR feedback.

Signed-off-by: Mike Balfour <82224783+mbalfour-amzn@users.noreply.github.com>

* Addressed PR feedback.
Simplified LoadInternal() by having it always use a GenericStream.

Signed-off-by: Mike Balfour <82224783+mbalfour-amzn@users.noreply.github.com>
This commit is contained in:
Mike Balfour
2021-12-21 16:28:44 -06:00
committed by GitHub
parent 44744d95b0
commit 845525a722
3 changed files with 139 additions and 19 deletions
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Gems/Atom/Utils/Code/Source/PngFile.cpp
+69 -17
View File
@@ -8,6 +8,7 @@
#include <Atom/Utils/PngFile.h>
#include <png.h>
#include <AzCore/IO/SystemFile.h>
namespace AZ
{
@@ -68,24 +69,66 @@ namespace AZ
{
if (!loadSettings.m_errorHandler)
{
loadSettings.m_errorHandler = [path](const char* message) { DefaultErrorHandler(AZStd::string::format("Could not load file '%s'. %s", path, message).c_str()); };
loadSettings.m_errorHandler = [path](const char* message)
{
DefaultErrorHandler(AZStd::string::format("Could not load file '%s'. %s", path, message).c_str());
};
}
// For documentation of this code, see http://www.libpng.org/pub/png/libpng-1.4.0-manual.pdf chapter 3
FILE* fp = NULL;
azfopen(&fp, path, "rb"); // return type differs across platforms so can't do inside if
if (!fp)
AZ::IO::SystemFile file;
file.Open(path, AZ::IO::SystemFile::SF_OPEN_READ_ONLY);
if (!file.IsOpen())
{
loadSettings.m_errorHandler("Cannot open file.");
return {};
}
constexpr bool StreamOwnsFilePointer = true;
AZ::IO::SystemFileStream fileLoadStream(&file, StreamOwnsFilePointer);
auto pngFile = LoadInternal(fileLoadStream, loadSettings);
return pngFile;
}
PngFile PngFile::LoadFromBuffer(AZStd::array_view<uint8_t> data, LoadSettings loadSettings)
{
if (!loadSettings.m_errorHandler)
{
loadSettings.m_errorHandler = [](const char* message)
{
DefaultErrorHandler(AZStd::string::format("Could not load Png from buffer. %s", message).c_str());
};
}
if (data.empty())
{
loadSettings.m_errorHandler("Buffer is empty.");
return {};
}
AZ::IO::MemoryStream memStream(data.data(), data.size());
return LoadInternal(memStream, loadSettings);
}
PngFile PngFile::LoadInternal(AZ::IO::GenericStream& dataStream, LoadSettings loadSettings)
{
// For documentation of this code, see http://www.libpng.org/pub/png/libpng-1.4.0-manual.pdf chapter 3
// Verify that we've passed in a valid data stream.
if (!dataStream.IsOpen() || !dataStream.CanRead())
{
loadSettings.m_errorHandler("Data stream isn't valid.");
return {};
}
png_byte header[HeaderSize] = {};
size_t headerBytesRead = 0;
if (fread(header, 1, HeaderSize, fp) != HeaderSize)
// This is the one I/O read that occurs outside of the png library, so either read from the file or the buffer and
// verify the results.
headerBytesRead = dataStream.Read(HeaderSize, header);
if (headerBytesRead != HeaderSize)
{
fclose(fp);
loadSettings.m_errorHandler("Invalid png header.");
return {};
}
@@ -93,7 +136,6 @@ namespace AZ
bool isPng = !png_sig_cmp(header, 0, HeaderSize);
if (!isPng)
{
fclose(fp);
loadSettings.m_errorHandler("Invalid png header.");
return {};
}
@@ -105,7 +147,6 @@ namespace AZ
png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, user_error_ptr, user_error_fn, user_warning_fn);
if (!png_ptr)
{
fclose(fp);
loadSettings.m_errorHandler("png_create_read_struct failed.");
return {};
}
@@ -114,7 +155,6 @@ namespace AZ
if (!info_ptr)
{
png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
fclose(fp);
loadSettings.m_errorHandler("png_create_info_struct failed.");
return {};
}
@@ -123,22 +163,35 @@ namespace AZ
if (!end_info)
{
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
fclose(fp);
loadSettings.m_errorHandler("png_create_info_struct failed.");
return {};
}
AZ_PUSH_DISABLE_WARNING(4611, "-Wunknown-warning-option") // Disables "interaction between '_setjmp' and C++ object destruction is non-portable". See https://docs.microsoft.com/en-us/cpp/preprocessor/warning?view=msvc-160
// Disables "interaction between '_setjmp' and C++ object destruction is non-portable".
// See https://docs.microsoft.com/en-us/cpp/preprocessor/warning?view=msvc-160
AZ_PUSH_DISABLE_WARNING(4611, "-Wunknown-warning-option")
if (setjmp(png_jmpbuf(png_ptr)))
{
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
fclose(fp);
// We don't report an error message here because the user_error_fn should have done that already.
return {};
}
AZ_POP_DISABLE_WARNING
png_init_io(png_ptr, fp);
auto genericStreamReader = [](png_structp pngPtr, png_bytep data, png_size_t length)
{
// Here we get our IO pointer back from the read struct.
// This should be the GenericStream pointer we passed to the png_set_read_fn() function.
png_voidp ioPtr = png_get_io_ptr(pngPtr);
if (ioPtr != nullptr)
{
AZ::IO::GenericStream* genericStream = static_cast<AZ::IO::GenericStream*>(ioPtr);
genericStream->Read(length, data);
}
};
png_set_read_fn(png_ptr, &dataStream, genericStreamReader);
png_set_sig_bytes(png_ptr, HeaderSize);
@@ -187,7 +240,6 @@ AZ_POP_DISABLE_WARNING
default:
AZ_Assert(false, "The png transforms should have ensured a pixel format of RGB or RGBA, 8 bits per channel");
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
fclose(fp);
loadSettings.m_errorHandler("Unsupported pixel format.");
return {};
}
@@ -201,7 +253,6 @@ AZ_POP_DISABLE_WARNING
}
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
fclose(fp);
return pngFile;
}
@@ -322,3 +373,4 @@ AZ_POP_DISABLE_WARNING
} // namespace Utils
}// namespace AZ