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82 lines
2.1 KiB
C++
82 lines
2.1 KiB
C++
/*
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* vcmi_endian.h, part of VCMI engine
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*
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* Authors: listed in file AUTHORS in main folder
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*
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* License: GNU General Public License v2.0 or later
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* Full text of license available in license.txt file, in main folder
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*
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*/
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#pragma once
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#include <boost/endian/conversion.hpp> //FIXME: use std::byteswap in C++23
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VCMI_LIB_NAMESPACE_BEGIN
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/* Reading values from memory.
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*
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* read_le_u16, read_le_u32 : read a little endian value from
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* memory. On big endian machines, the value will be byteswapped.
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*/
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#if defined(__clang__) || defined(__GNUC__) || defined(_MSC_VER)
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#if defined(_MSC_VER)
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#define PACKED_STRUCT_BEGIN __pragma( pack(push, 1) )
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#define PACKED_STRUCT_END __pragma( pack(pop) )
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#else
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#define PACKED_STRUCT_BEGIN
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#define PACKED_STRUCT_END __attribute__(( packed ))
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#endif
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PACKED_STRUCT_BEGIN struct unaligned_Uint16 { ui16 val; } PACKED_STRUCT_END;
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PACKED_STRUCT_BEGIN struct unaligned_Uint32 { ui32 val; } PACKED_STRUCT_END;
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static inline ui16 read_unaligned_u16(const void *p)
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{
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const auto * v = reinterpret_cast<const struct unaligned_Uint16 *>(p);
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return v->val;
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}
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static inline ui32 read_unaligned_u32(const void *p)
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{
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const auto * v = reinterpret_cast<const struct unaligned_Uint32 *>(p);
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return v->val;
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}
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#define read_le_u16(p) (boost::endian::native_to_little(read_unaligned_u16(p)))
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#define read_le_u32(p) (boost::endian::native_to_little(read_unaligned_u32(p)))
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#else
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#warning UB: unaligned memory access
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#define read_le_u16(p) (boost::endian::native_to_little(* reinterpret_cast<const ui16 *>(p)))
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#define read_le_u32(p) (boost::endian::native_to_little(* reinterpret_cast<const ui32 *>(p)))
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#define PACKED_STRUCT_BEGIN
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#define PACKED_STRUCT_END
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#endif
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static inline char readChar(const ui8 * buffer, int & i)
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{
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return buffer[i++];
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}
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static inline std::string readString(const ui8 * buffer, int & i)
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{
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int len = read_le_u32(buffer + i);
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i += 4;
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assert(len >= 0 && len <= 500000); //not too long
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std::string ret;
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ret.reserve(len);
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for(int gg = 0; gg < len; ++gg)
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{
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ret += buffer[i++];
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}
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return ret;
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}
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VCMI_LIB_NAMESPACE_END
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