mirror of
https://github.com/matrix-construct/construct
synced 2024-10-01 05:08:59 +02:00
109 lines
2.6 KiB
C++
109 lines
2.6 KiB
C++
// The Construct
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//
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// Copyright (C) The Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2021 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#include <RB_INC_PNG_H
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decltype(ircd::png::version_api)
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ircd::png::version_api
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{
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"png", info::versions::API,
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#ifdef HAVE_PNG_H
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PNG_LIBPNG_VER,
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{
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PNG_LIBPNG_VER_MAJOR,
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PNG_LIBPNG_VER_MINOR,
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PNG_LIBPNG_VER_RELEASE,
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},
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rstrip(lstrip(PNG_HEADER_VERSION_STRING, " "), "\n")
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#endif
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};
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/// Since libpng may not have loaded prior to static initialization there is
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/// no linked library identification. libmagick takes care of loading libpng
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/// dynamically if it requires it for us.
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decltype(ircd::png::version_abi)
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ircd::png::version_abi
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{
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"png", info::versions::ABI,
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};
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bool
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ircd::png::is_animated(const const_buffer &buf)
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#ifdef PNG_APNG_SUPPORTED
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{
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// Cannot be a PNG
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if(unlikely(size(buf) < 8))
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return false;
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png_infop info {nullptr};
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png_structp handle {nullptr};
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const unwind destroy
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{
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[&handle, &info]
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{
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png_destroy_read_struct(&handle, &info, nullptr);
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}
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};
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if(unlikely(!(handle = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr))))
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return false;
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if(unlikely(!(info = png_create_info_struct(handle))))
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return false;
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const_buffer src{buf};
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png_set_read_fn(handle, &src, []
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(auto handle, uint8_t *const ptr, size_t sz)
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{
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// Destination where libpng wants data
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const mutable_buffer dst
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{
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reinterpret_cast<char *>(ptr), sz
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};
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// Get source buffer from our callback user data.
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const_buffer &src
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{
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*reinterpret_cast<const_buffer *>(png_get_io_ptr(handle))
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};
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// Copy from our buffer to libpng buffer.
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const size_t copied
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{
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copy(dst, src)
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};
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// Advance our source pointer for the amount copied.
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const size_t consumed
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{
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consume(src, copied)
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};
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assert(copied == consumed);
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});
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// Invokes the read callback a few times to traverse the buffer.
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png_read_info(handle, info);
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// If there's a non-zero result there's acTL for animation.
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uint32_t frames(0), plays(0);
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if(png_get_acTL(handle, info, &frames, &plays) != 0)
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return true;
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return false;
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}
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#else
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{
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// If there's no libpng there's no reason to decide APNG's right now
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// because they won't be thumbnailed by magick anyway.
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#warning "Upgrade your libpng version for animation detection."
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return false;
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}
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#endif
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