1 // int_encoding.h -- variable length and unaligned integers -*- C++ -*-
3 // Copyright (C) 2009-2018 Free Software Foundation, Inc.
4 // Written by Doug Kwan <dougkwan@google.com> by refactoring scattered
5 // contents from other files in gold. Original code written by Ian
6 // Lance Taylor <iant@google.com> and Caleb Howe <cshowe@google.com>.
8 // This file is part of gold.
10 // This program is free software; you can redistribute it and/or modify
11 // it under the terms of the GNU General Public License as published by
12 // the Free Software Foundation; either version 3 of the License, or
13 // (at your option) any later version.
15 // This program is distributed in the hope that it will be useful,
16 // but WITHOUT ANY WARRANTY; without even the implied warranty of
17 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 // GNU General Public License for more details.
20 // You should have received a copy of the GNU General Public License
21 // along with this program; if not, write to the Free Software
22 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
23 // MA 02110-1301, USA.
25 #ifndef GOLD_INT_ENCODING_H
26 #define GOLD_INT_ENCODING_H
31 #include "parameters.h"
37 // LEB 128 encoding support.
40 // Read a ULEB 128 encoded integer from BUFFER. Return the length of the
41 // encoded integer at the location PLEN. The common case of a single-byte
42 // value is handled inline, and multi-byte values are processed by the _x
43 // routine, where BYTE is the first byte of the value.
46 read_unsigned_LEB_128_x(const unsigned char* buffer
, size_t* plen
,
50 read_unsigned_LEB_128(const unsigned char* buffer
, size_t* plen
)
52 unsigned char byte
= *buffer
++;
54 if ((byte
& 0x80) != 0)
55 return read_unsigned_LEB_128_x(buffer
, plen
, byte
);
58 return static_cast<uint64_t>(byte
);
61 // Read an SLEB 128 encoded integer from BUFFER. Return the length of the
62 // encoded integer at the location PLEN. The common case of a single-byte
63 // value is handled inline, and multi-byte values are processed by the _x
64 // routine, where BYTE is the first byte of the value.
67 read_signed_LEB_128_x(const unsigned char* buffer
, size_t* plen
,
71 read_signed_LEB_128(const unsigned char* buffer
, size_t* plen
)
73 unsigned char byte
= *buffer
++;
75 if ((byte
& 0x80) != 0)
76 return read_signed_LEB_128_x(buffer
, plen
, byte
);
80 return -(static_cast<int64_t>(1) << 7) | static_cast<int64_t>(byte
);
81 return static_cast<int64_t>(byte
);
84 // Write a ULEB 128 encoded VALUE to BUFFER.
87 write_unsigned_LEB_128(std::vector
<unsigned char>* buffer
, uint64_t value
);
89 // Return the ULEB 128 encoded size of VALUE.
92 get_length_as_unsigned_LEB_128(uint64_t value
);
95 // Unaligned integer encoding support.
98 // Insert VALSIZE-bit integer VALUE into DESTINATION.
100 template <int valsize
>
101 void insert_into_vector(std::vector
<unsigned char>* destination
,
102 typename
elfcpp::Valtype_base
<valsize
>::Valtype value
)
104 unsigned char buffer
[valsize
/ 8];
105 if (parameters
->target().is_big_endian())
106 elfcpp::Swap_unaligned
<valsize
, true>::writeval(buffer
, value
);
108 elfcpp::Swap_unaligned
<valsize
, false>::writeval(buffer
, value
);
109 destination
->insert(destination
->end(), buffer
, buffer
+ valsize
/ 8);
112 // Read a possibly unaligned integer of SIZE from SOURCE.
114 template <int valsize
>
115 typename
elfcpp::Valtype_base
<valsize
>::Valtype
116 read_from_pointer(const unsigned char* source
)
118 typename
elfcpp::Valtype_base
<valsize
>::Valtype return_value
;
119 if (parameters
->target().is_big_endian())
120 return_value
= elfcpp::Swap_unaligned
<valsize
, true>::readval(source
);
122 return_value
= elfcpp::Swap_unaligned
<valsize
, false>::readval(source
);
126 // Read a possibly unaligned integer of SIZE. Update SOURCE after read.
128 template <int valsize
>
129 typename
elfcpp::Valtype_base
<valsize
>::Valtype
130 read_from_pointer(unsigned char** source
)
132 typename
elfcpp::Valtype_base
<valsize
>::Valtype return_value
;
133 if (parameters
->target().is_big_endian())
134 return_value
= elfcpp::Swap_unaligned
<valsize
, true>::readval(*source
);
136 return_value
= elfcpp::Swap_unaligned
<valsize
, false>::readval(*source
);
137 *source
+= valsize
/ 8;
141 // Same as the above except for use with const unsigned char data.
143 template <int valsize
>
144 typename
elfcpp::Valtype_base
<valsize
>::Valtype
145 read_from_pointer(const unsigned char** source
)
147 typename
elfcpp::Valtype_base
<valsize
>::Valtype return_value
;
148 if (parameters
->target().is_big_endian())
149 return_value
= elfcpp::Swap_unaligned
<valsize
, true>::readval(*source
);
151 return_value
= elfcpp::Swap_unaligned
<valsize
, false>::readval(*source
);
152 *source
+= valsize
/ 8;
156 } // End namespace gold.
158 #endif // !defined(GOLD_INT_ENCODING_H)
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