| 1 | // |
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| 2 | // SPDX-License-Identifier: BSD-3-Clause |
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| 3 | // Copyright (c) Contributors to the OpenEXR Project. |
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| 4 | // |
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| 5 | |
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| 6 | #ifndef INCLUDED_IMF_VERSION_H |
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| 7 | #define INCLUDED_IMF_VERSION_H |
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| 8 | |
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| 9 | //----------------------------------------------------------------------------- |
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| 10 | // |
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| 11 | // Magic and version number. |
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| 12 | // |
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| 13 | //----------------------------------------------------------------------------- |
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| 14 | |
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| 15 | #include "ImfExport.h" |
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| 16 | #include "ImfNamespace.h" |
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| 17 | |
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| 18 | OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_ENTER |
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| 19 | |
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| 20 | // |
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| 21 | // The MAGIC number is stored in the first four bytes of every |
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| 22 | // OpenEXR image file. This can be used to quickly test whether |
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| 23 | // a given file is an OpenEXR image file (see isImfMagic(), below). |
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| 24 | // |
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| 25 | |
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| 26 | static const int MAGIC = 20000630; |
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| 27 | |
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| 28 | |
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| 29 | // |
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| 30 | // The second item in each OpenEXR image file, right after the |
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| 31 | // magic number, is a four-byte file version identifier. Depending |
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| 32 | // on a file's version identifier, a file reader can enable various |
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| 33 | // backwards-compatibility switches, or it can quickly reject files |
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| 34 | // that it cannot read. |
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| 35 | // |
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| 36 | // The version identifier is split into an 8-bit version number, |
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| 37 | // and a 24-bit flags field. |
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| 38 | // |
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| 39 | |
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| 40 | static const int VERSION_NUMBER_FIELD = 0x000000ff; |
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| 41 | static const int VERSION_FLAGS_FIELD = 0xffffff00; |
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| 42 | |
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| 43 | |
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| 44 | // |
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| 45 | // Value that goes into VERSION_NUMBER_FIELD. |
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| 46 | // |
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| 47 | |
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| 48 | static const int EXR_VERSION = 2; |
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| 49 | |
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| 50 | |
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| 51 | // |
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| 52 | // Flags that can go into VERSION_FLAGS_FIELD. |
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| 53 | // Flags can only occupy the 1 bits in VERSION_FLAGS_FIELD. |
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| 54 | // |
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| 55 | |
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| 56 | static const int TILED_FLAG = 0x00000200; // File is tiled |
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| 57 | static |
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| 58 | const int LONG_NAMES_FLAG = 0x00000400; // File contains long |
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| 59 | // attribute or channel |
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| 60 | // names |
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| 61 | static |
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| 62 | const int NON_IMAGE_FLAG = 0x00000800; // File has at least one part |
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| 63 | // which is not a regular |
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| 64 | // scanline image or regular tiled image |
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| 65 | // (that is, it is a deep format) |
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| 66 | static |
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| 67 | const int MULTI_PART_FILE_FLAG = 0x00001000; // File has multiple parts |
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| 68 | |
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| 69 | // |
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| 70 | // Bitwise OR of all known flags. |
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| 71 | // |
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| 72 | static |
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| 73 | const int ALL_FLAGS = TILED_FLAG | LONG_NAMES_FLAG | |
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| 74 | NON_IMAGE_FLAG | MULTI_PART_FILE_FLAG; |
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| 75 | |
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| 76 | |
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| 77 | // |
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| 78 | // Utility functions |
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| 79 | // |
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| 80 | |
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| 81 | inline bool isTiled (int version) {return !!(version & TILED_FLAG);} |
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| 82 | inline bool isMultiPart (int version) {return !!(version & MULTI_PART_FILE_FLAG); } |
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| 83 | inline bool isNonImage(int version) {return !!(version & NON_IMAGE_FLAG); } |
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| 84 | inline int makeTiled (int version) {return version | TILED_FLAG;} |
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| 85 | inline int makeNotTiled (int version) {return version & ~TILED_FLAG;} |
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| 86 | inline int getVersion (int version) {return version & VERSION_NUMBER_FIELD;} |
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| 87 | inline int getFlags (int version) {return version & VERSION_FLAGS_FIELD;} |
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| 88 | inline bool supportsFlags (int flags) {return !(flags & ~ALL_FLAGS);} |
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| 89 | |
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| 90 | |
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| 91 | // |
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| 92 | // Given the first four bytes of a file, returns true if the |
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| 93 | // file is probably an OpenEXR image file, false if not. |
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| 94 | // |
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| 95 | |
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| 96 | IMF_EXPORT |
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| 97 | bool isImfMagic (const char bytes[4]); |
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| 98 | |
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| 99 | |
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| 100 | OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_EXIT |
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| 101 | |
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| 102 | |
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| 103 | |
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| 104 | |
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| 105 | |
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| 106 | #endif |
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| 107 | |
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