mirror of
https://github.com/matrix-construct/construct
synced 2024-11-13 21:41:06 +01:00
110 lines
2.4 KiB
C++
110 lines
2.4 KiB
C++
// Matrix Construct
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//
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// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2019 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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namespace ircd::cbor
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{
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static uint8_t _major(const uint8_t &); // Major type
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static uint8_t _minor(const uint8_t &); // Minor type
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static size_t _length(const uint8_t &); // (1 + size(following()))
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}
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size_t
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ircd::cbor::_length(const uint8_t &a)
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{
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switch(_major(a))
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{
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case POSITIVE:
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case NEGATIVE:
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case BINARY:
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case STRING:
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case ARRAY:
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case OBJECT:
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case TAG:
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{
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if(_minor(a) > 23) switch(_minor(a))
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{
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case minor::U8: return 2;
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case minor::U16: return 3;
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case minor::U32: return 5;
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case minor::U64: return 9;
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default: throw type_error
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{
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"Unknown minor type (%u); length of header unknown",
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_minor(a)
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};
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}
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else return 1;
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}
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case PRIMITIVE:
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{
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if(_minor(a) > 23) switch(_minor(a))
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{
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case FALSE:
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case TRUE:
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case NUL:
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case UD: return 1;
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case minor::F16: return 3;
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case minor::F32: return 5;
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case minor::F64: return 9;
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default: throw type_error
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{
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"Unknown primitive minor type (%u); length of header unknown",
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_minor(a)
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};
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}
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else return 1;
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}
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default: throw type_error
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{
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"Unknown major type; length of header unknown"
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};
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}
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}
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/// Extract major type from leading head byte (arg)
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uint8_t
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ircd::cbor::_major(const uint8_t &a)
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{
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// shift for higher 3 bits only
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return a >> 5;
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}
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/// Extract minor type from leading head byte (arg)
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uint8_t
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ircd::cbor::_minor(const uint8_t &a)
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{
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// mask of lower 5 bits only
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static const uint8_t mask
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{
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uint8_t(0xFF) >> 3
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};
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return a & mask;
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}
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ircd::string_view
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ircd::cbor::reflect(const enum major &major)
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{
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switch(major)
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{
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case major::POSITIVE: return "POSITIVE";
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case major::NEGATIVE: return "NEGATIVE";
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case major::BINARY: return "BINARY";
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case major::STRING: return "STRING";
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case major::ARRAY: return "ARRAY";
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case major::OBJECT: return "OBJECT";
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case major::TAG: return "TAG";
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case major::PRIMITIVE: return "PRIMITIVE";
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}
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return "??????";
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}
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