| /* Utilities for reading leb128 values. |
| Copyright (C) 2012-2022 Free Software Foundation, Inc. |
| |
| This file is part of the libiberty library. |
| Libiberty is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Library General Public |
| License as published by the Free Software Foundation; either |
| version 2 of the License, or (at your option) any later version. |
| |
| Libiberty is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Library General Public License for more details. |
| |
| You should have received a copy of the GNU Library General Public |
| License along with libiberty; see the file COPYING.LIB. If not, write |
| to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, |
| Boston, MA 02110-1301, USA. */ |
| |
| /* The functions defined here can be speed critical. |
| Since they are all pretty small we keep things simple and just define |
| them all as "static inline". |
| |
| WARNING: This file is used by GDB which is stuck at C90. :-( |
| Though it can use stdint.h, inttypes.h. |
| Therefore if you want to add support for "long long" you need |
| to wrap it in #ifdef CC_HAS_LONG_LONG. */ |
| |
| #ifndef LEB128_H |
| #define LEB128_H |
| |
| /* Get a definition for inline. */ |
| #include "ansidecl.h" |
| |
| /* Get a definition for NULL, size_t. */ |
| #include <stddef.h> |
| |
| #ifdef HAVE_STDINT_H |
| #include <stdint.h> |
| #endif |
| #ifdef HAVE_INTTYPES_H |
| #include <inttypes.h> |
| #endif |
| |
| /* Decode the unsigned LEB128 constant at BUF into the variable pointed to |
| by R, and return the number of bytes read. |
| If we read off the end of the buffer, zero is returned, |
| and nothing is stored in R. |
| |
| Note: The result is an int instead of a pointer to the next byte to be |
| read to avoid const-vs-non-const problems. */ |
| |
| static inline size_t |
| read_uleb128_to_uint64 (const unsigned char *buf, const unsigned char *buf_end, |
| uint64_t *r) |
| { |
| const unsigned char *p = buf; |
| unsigned int shift = 0; |
| uint64_t result = 0; |
| unsigned char byte; |
| |
| while (1) |
| { |
| if (p >= buf_end) |
| return 0; |
| |
| byte = *p++; |
| result |= ((uint64_t) (byte & 0x7f)) << shift; |
| if ((byte & 0x80) == 0) |
| break; |
| shift += 7; |
| } |
| |
| *r = result; |
| return p - buf; |
| } |
| |
| /* Decode the signed LEB128 constant at BUF into the variable pointed to |
| by R, and return the number of bytes read. |
| If we read off the end of the buffer, zero is returned, |
| and nothing is stored in R. |
| |
| Note: The result is an int instead of a pointer to the next byte to be |
| read to avoid const-vs-non-const problems. */ |
| |
| static inline size_t |
| read_sleb128_to_int64 (const unsigned char *buf, const unsigned char *buf_end, |
| int64_t *r) |
| { |
| const unsigned char *p = buf; |
| unsigned int shift = 0; |
| int64_t result = 0; |
| unsigned char byte; |
| |
| while (1) |
| { |
| if (p >= buf_end) |
| return 0; |
| |
| byte = *p++; |
| result |= ((uint64_t) (byte & 0x7f)) << shift; |
| shift += 7; |
| if ((byte & 0x80) == 0) |
| break; |
| } |
| if (shift < (sizeof (*r) * 8) && (byte & 0x40) != 0) |
| result |= -(((uint64_t) 1) << shift); |
| |
| *r = result; |
| return p - buf; |
| } |
| |
| /* Return the number of bytes to read to skip past an LEB128 number in BUF. |
| If the end isn't found before reaching BUF_END, return zero. |
| |
| Note: The result is an int instead of a pointer to the next byte to be |
| read to avoid const-vs-non-const problems. */ |
| |
| static inline size_t |
| skip_leb128 (const unsigned char *buf, const unsigned char *buf_end) |
| { |
| const unsigned char *p = buf; |
| unsigned char byte; |
| |
| while (1) |
| { |
| if (p == buf_end) |
| return 0; |
| |
| byte = *p++; |
| if ((byte & 0x80) == 0) |
| return p - buf; |
| } |
| } |
| |
| #endif /* LEB128_H */ |