125 lines
2.9 KiB
C
125 lines
2.9 KiB
C
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//
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// SPDX-License-Identifier: BSD-3-Clause
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// Copyright (c) Contributors to the OpenEXR Project.
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//
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#ifndef INCLUDED_IMF_VERSION_H
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#define INCLUDED_IMF_VERSION_H
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//-----------------------------------------------------------------------------
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//
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// Magic and version number.
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//
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//-----------------------------------------------------------------------------
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#include "ImfExport.h"
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#include "ImfNamespace.h"
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OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_ENTER
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//
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// The MAGIC number is stored in the first four bytes of every
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// OpenEXR image file. This can be used to quickly test whether
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// a given file is an OpenEXR image file (see isImfMagic(), below).
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//
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static const int MAGIC = 20000630;
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//
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// The second item in each OpenEXR image file, right after the
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// magic number, is a four-byte file version identifier. Depending
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// on a file's version identifier, a file reader can enable various
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// backwards-compatibility switches, or it can quickly reject files
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// that it cannot read.
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//
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// The version identifier is split into an 8-bit version number,
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// and a 24-bit flags field.
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//
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static const int VERSION_NUMBER_FIELD = 0x000000ff;
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static const int VERSION_FLAGS_FIELD = 0xffffff00;
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//
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// Value that goes into VERSION_NUMBER_FIELD.
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//
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static const int EXR_VERSION = 2;
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//
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// Flags that can go into VERSION_FLAGS_FIELD.
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// Flags can only occupy the 1 bits in VERSION_FLAGS_FIELD.
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//
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static const int TILED_FLAG = 0x00000200; // File is tiled
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static const int LONG_NAMES_FLAG = 0x00000400; // File contains long
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// attribute or channel
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// names
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static const int NON_IMAGE_FLAG = 0x00000800; // File has at least one part
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// which is not a regular
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// scanline image or regular tiled image
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// (that is, it is a deep format)
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static const int MULTI_PART_FILE_FLAG = 0x00001000; // File has multiple parts
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//
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// Bitwise OR of all known flags.
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//
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static const int ALL_FLAGS =
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TILED_FLAG | LONG_NAMES_FLAG | NON_IMAGE_FLAG | MULTI_PART_FILE_FLAG;
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//
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// Utility functions
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//
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inline bool
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isTiled (int version)
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{
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return !!(version & TILED_FLAG);
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}
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inline bool
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isMultiPart (int version)
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{
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return !!(version & MULTI_PART_FILE_FLAG);
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}
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inline bool
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isNonImage (int version)
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{
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return !!(version & NON_IMAGE_FLAG);
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}
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inline int
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makeTiled (int version)
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{
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return version | TILED_FLAG;
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}
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inline int
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makeNotTiled (int version)
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{
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return version & ~TILED_FLAG;
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}
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inline int
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getVersion (int version)
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{
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return version & VERSION_NUMBER_FIELD;
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}
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inline int
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getFlags (int version)
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{
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return version & VERSION_FLAGS_FIELD;
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}
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inline bool
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supportsFlags (int flags)
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{
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return !(flags & ~ALL_FLAGS);
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}
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//
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// Given the first four bytes of a file, returns true if the
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// file is probably an OpenEXR image file, false if not.
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//
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IMF_EXPORT
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bool isImfMagic (const char bytes[4]);
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OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_EXIT
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#endif
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