OLD | NEW |
(Empty) | |
| 1 /* Utilities for reading leb128 values. |
| 2 Copyright (C) 2012 Free Software Foundation, Inc. |
| 3 |
| 4 This file is part of the libiberty library. |
| 5 Libiberty is free software; you can redistribute it and/or |
| 6 modify it under the terms of the GNU Library General Public |
| 7 License as published by the Free Software Foundation; either |
| 8 version 2 of the License, or (at your option) any later version. |
| 9 |
| 10 Libiberty is distributed in the hope that it will be useful, |
| 11 but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 Library General Public License for more details. |
| 14 |
| 15 You should have received a copy of the GNU Library General Public |
| 16 License along with libiberty; see the file COPYING.LIB. If not, write |
| 17 to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, |
| 18 Boston, MA 02110-1301, USA. */ |
| 19 |
| 20 /* The functions defined here can be speed critical. |
| 21 Since they are all pretty small we keep things simple and just define |
| 22 them all as "static inline". |
| 23 |
| 24 WARNING: This file is used by GDB which is stuck at C90. :-( |
| 25 Though it can use stdint.h, inttypes.h. |
| 26 Therefore if you want to add support for "long long" you need |
| 27 to wrap it in #ifdef CC_HAS_LONG_LONG. */ |
| 28 |
| 29 #ifndef LEB128_H |
| 30 #define LEB128_H |
| 31 |
| 32 /* Get a definition for inline. */ |
| 33 #include "ansidecl.h" |
| 34 |
| 35 /* Get a definition for NULL, size_t. */ |
| 36 #include <stddef.h> |
| 37 |
| 38 #ifdef HAVE_STDINT_H |
| 39 #include <stdint.h> |
| 40 #endif |
| 41 #ifdef HAVE_INTTYPES_H |
| 42 #include <inttypes.h> |
| 43 #endif |
| 44 |
| 45 /* Decode the unsigned LEB128 constant at BUF into the variable pointed to |
| 46 by R, and return the number of bytes read. |
| 47 If we read off the end of the buffer, zero is returned, |
| 48 and nothing is stored in R. |
| 49 |
| 50 Note: The result is an int instead of a pointer to the next byte to be |
| 51 read to avoid const-vs-non-const problems. */ |
| 52 |
| 53 static inline size_t |
| 54 read_uleb128_to_uint64 (const unsigned char *buf, const unsigned char *buf_end, |
| 55 uint64_t *r) |
| 56 { |
| 57 const unsigned char *p = buf; |
| 58 unsigned int shift = 0; |
| 59 uint64_t result = 0; |
| 60 unsigned char byte; |
| 61 |
| 62 while (1) |
| 63 { |
| 64 if (p >= buf_end) |
| 65 return 0; |
| 66 |
| 67 byte = *p++; |
| 68 result |= ((uint64_t) (byte & 0x7f)) << shift; |
| 69 if ((byte & 0x80) == 0) |
| 70 break; |
| 71 shift += 7; |
| 72 } |
| 73 |
| 74 *r = result; |
| 75 return p - buf; |
| 76 } |
| 77 |
| 78 /* Decode the signed LEB128 constant at BUF into the variable pointed to |
| 79 by R, and return the number of bytes read. |
| 80 If we read off the end of the buffer, zero is returned, |
| 81 and nothing is stored in R. |
| 82 |
| 83 Note: The result is an int instead of a pointer to the next byte to be |
| 84 read to avoid const-vs-non-const problems. */ |
| 85 |
| 86 static inline size_t |
| 87 read_sleb128_to_int64 (const unsigned char *buf, const unsigned char *buf_end, |
| 88 int64_t *r) |
| 89 { |
| 90 const unsigned char *p = buf; |
| 91 unsigned int shift = 0; |
| 92 int64_t result = 0; |
| 93 unsigned char byte; |
| 94 |
| 95 while (1) |
| 96 { |
| 97 if (p >= buf_end) |
| 98 return 0; |
| 99 |
| 100 byte = *p++; |
| 101 result |= ((uint64_t) (byte & 0x7f)) << shift; |
| 102 shift += 7; |
| 103 if ((byte & 0x80) == 0) |
| 104 break; |
| 105 } |
| 106 if (shift < (sizeof (*r) * 8) && (byte & 0x40) != 0) |
| 107 result |= -(((uint64_t) 1) << shift); |
| 108 |
| 109 *r = result; |
| 110 return p - buf; |
| 111 } |
| 112 |
| 113 /* Return the number of bytes to read to skip past an LEB128 number in BUF. |
| 114 If the end isn't found before reaching BUF_END, return zero. |
| 115 |
| 116 Note: The result is an int instead of a pointer to the next byte to be |
| 117 read to avoid const-vs-non-const problems. */ |
| 118 |
| 119 static inline size_t |
| 120 skip_leb128 (const unsigned char *buf, const unsigned char *buf_end) |
| 121 { |
| 122 const unsigned char *p = buf; |
| 123 unsigned char byte; |
| 124 |
| 125 while (1) |
| 126 { |
| 127 if (p == buf_end) |
| 128 return 0; |
| 129 |
| 130 byte = *p++; |
| 131 if ((byte & 0x80) == 0) |
| 132 return p - buf; |
| 133 } |
| 134 } |
| 135 |
| 136 #endif /* LEB128_H */ |
OLD | NEW |