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5191 | serge | 1 | /* Utilities for reading leb128 values. |
6324 | serge | 2 | Copyright (C) 2012-2015 Free Software Foundation, Inc. |
5191 | serge | 3 | |
4 | This file is part of the libiberty library. |
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5 | Libiberty is free software; you can redistribute it and/or |
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6 | modify it under the terms of the GNU Library General Public |
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7 | License as published by the Free Software Foundation; either |
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8 | version 2 of the License, or (at your option) any later version. |
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9 | |||
10 | Libiberty is distributed in the hope that it will be useful, |
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11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 | Library General Public License for more details. |
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14 | |||
15 | You should have received a copy of the GNU Library General Public |
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16 | License along with libiberty; see the file COPYING.LIB. If not, write |
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17 | to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, |
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18 | Boston, MA 02110-1301, USA. */ |
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19 | |||
20 | /* The functions defined here can be speed critical. |
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21 | Since they are all pretty small we keep things simple and just define |
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22 | them all as "static inline". |
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23 | |||
24 | WARNING: This file is used by GDB which is stuck at C90. :-( |
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25 | Though it can use stdint.h, inttypes.h. |
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26 | Therefore if you want to add support for "long long" you need |
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27 | to wrap it in #ifdef CC_HAS_LONG_LONG. */ |
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28 | |||
29 | #ifndef LEB128_H |
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30 | #define LEB128_H |
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31 | |||
32 | /* Get a definition for inline. */ |
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33 | #include "ansidecl.h" |
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34 | |||
35 | /* Get a definition for NULL, size_t. */ |
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36 | #include |
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37 | |||
38 | #ifdef HAVE_STDINT_H |
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39 | #include |
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40 | #endif |
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41 | #ifdef HAVE_INTTYPES_H |
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42 | #include |
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43 | #endif |
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44 | |||
45 | /* Decode the unsigned LEB128 constant at BUF into the variable pointed to |
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46 | by R, and return the number of bytes read. |
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47 | If we read off the end of the buffer, zero is returned, |
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48 | and nothing is stored in R. |
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49 | |||
50 | Note: The result is an int instead of a pointer to the next byte to be |
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51 | read to avoid const-vs-non-const problems. */ |
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52 | |||
53 | static inline size_t |
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54 | read_uleb128_to_uint64 (const unsigned char *buf, const unsigned char *buf_end, |
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55 | uint64_t *r) |
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56 | { |
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57 | const unsigned char *p = buf; |
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58 | unsigned int shift = 0; |
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59 | uint64_t result = 0; |
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60 | unsigned char byte; |
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61 | |||
62 | while (1) |
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63 | { |
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64 | if (p >= buf_end) |
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65 | return 0; |
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66 | |||
67 | byte = *p++; |
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68 | result |= ((uint64_t) (byte & 0x7f)) << shift; |
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69 | if ((byte & 0x80) == 0) |
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70 | break; |
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71 | shift += 7; |
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72 | } |
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73 | |||
74 | *r = result; |
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75 | return p - buf; |
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76 | } |
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77 | |||
78 | /* Decode the signed LEB128 constant at BUF into the variable pointed to |
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79 | by R, and return the number of bytes read. |
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80 | If we read off the end of the buffer, zero is returned, |
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81 | and nothing is stored in R. |
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82 | |||
83 | Note: The result is an int instead of a pointer to the next byte to be |
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84 | read to avoid const-vs-non-const problems. */ |
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85 | |||
86 | static inline size_t |
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87 | read_sleb128_to_int64 (const unsigned char *buf, const unsigned char *buf_end, |
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88 | int64_t *r) |
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89 | { |
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90 | const unsigned char *p = buf; |
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91 | unsigned int shift = 0; |
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92 | int64_t result = 0; |
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93 | unsigned char byte; |
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94 | |||
95 | while (1) |
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96 | { |
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97 | if (p >= buf_end) |
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98 | return 0; |
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99 | |||
100 | byte = *p++; |
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101 | result |= ((uint64_t) (byte & 0x7f)) << shift; |
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102 | shift += 7; |
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103 | if ((byte & 0x80) == 0) |
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104 | break; |
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105 | } |
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106 | if (shift < (sizeof (*r) * 8) && (byte & 0x40) != 0) |
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107 | result |= -(((uint64_t) 1) << shift); |
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108 | |||
109 | *r = result; |
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110 | return p - buf; |
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111 | } |
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112 | |||
113 | /* Return the number of bytes to read to skip past an LEB128 number in BUF. |
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114 | If the end isn't found before reaching BUF_END, return zero. |
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115 | |||
116 | Note: The result is an int instead of a pointer to the next byte to be |
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117 | read to avoid const-vs-non-const problems. */ |
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118 | |||
119 | static inline size_t |
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120 | skip_leb128 (const unsigned char *buf, const unsigned char *buf_end) |
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121 | { |
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122 | const unsigned char *p = buf; |
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123 | unsigned char byte; |
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124 | |||
125 | while (1) |
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126 | { |
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127 | if (p == buf_end) |
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128 | return 0; |
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129 | |||
130 | byte = *p++; |
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131 | if ((byte & 0x80) == 0) |
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132 | return p - buf; |
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133 | } |
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134 | } |
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135 | |||
136 | #endif /* LEB128_H */><>>><>><> |