1 /* 2 3 Copyright (C) 2000,2004 Silicon Graphics, Inc. All Rights Reserved. 4 Portions Copyright 2011 David Anderson. All Rights Reserved. 5 6 This program is free software; you can redistribute it and/or modify it 7 under the terms of version 2.1 of the GNU Lesser General Public License 8 as published by the Free Software Foundation. 9 10 This program is distributed in the hope that it would be useful, but 11 WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 13 14 Further, this software is distributed without any warranty that it is 15 free of the rightful claim of any third person regarding infringement 16 or the like. Any license provided herein, whether implied or 17 otherwise, applies only to this software file. Patent licenses, if 18 any, provided herein do not apply to combinations of this program with 19 other software, or any other product whatsoever. 20 21 You should have received a copy of the GNU Lesser General Public 22 License along with this program; if not, write the Free Software 23 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston MA 02110-1301, 24 USA. 25 26 */ 27 28 #include "config.h" 29 #include "libdwarfdefs.h" 30 #include <string.h> 31 #include "dwarf.h" 32 #include "libdwarf.h" 33 #include "pro_encode_nm.h" 34 35 #define MORE_BYTES 0x80 36 #define DATA_MASK 0x7f 37 #define DIGIT_WIDTH 7 38 #define SIGN_BIT 0x40 39 40 41 /* Encode val as a leb128. This encodes it as an unsigned 42 number. */ 43 /* Return DW_DLV_ERROR or DW_DLV_OK. 44 space to write leb number is provided by caller, with caller 45 passing length. 46 number of bytes used returned thru nbytes arg */ 47 int 48 _dwarf_pro_encode_leb128_nm(Dwarf_Unsigned val, int *nbytes, 49 char *space, int splen) 50 { 51 char *a; 52 char *end = space + splen; 53 54 a = space; 55 do { 56 unsigned char uc; 57 58 if (a >= end) { 59 return DW_DLV_ERROR; 60 } 61 uc = val & DATA_MASK; 62 val >>= DIGIT_WIDTH; 63 if (val != 0) { 64 uc |= MORE_BYTES; 65 } 66 *a = uc; 67 a++; 68 } while (val); 69 *nbytes = (int)(a - space); 70 return DW_DLV_OK; 71 } 72 73 /* return DW_DLV_ERROR or DW_DLV_OK. 74 ** space to write leb number is provided by caller, with caller 75 ** passing length. 76 ** number of bytes used returned thru nbytes arg 77 ** encodes a signed number. 78 */ 79 int 80 _dwarf_pro_encode_signed_leb128_nm(Dwarf_Signed value, int *nbytes, 81 char *space, int splen) 82 { 83 char *str; 84 Dwarf_Signed sign = -(value < 0); 85 int more = 1; 86 char *end = space + splen; 87 88 str = space; 89 90 do { 91 unsigned char byte = value & DATA_MASK; 92 93 value >>= DIGIT_WIDTH; 94 95 if (str >= end) { 96 return DW_DLV_ERROR; 97 } 98 /* Remaining chunks would just contain the sign bit, and this chunk 99 has already captured at least one sign bit. */ 100 if (value == sign && ((byte & SIGN_BIT) == (sign & SIGN_BIT))) { 101 more = 0; 102 } else { 103 byte |= MORE_BYTES; 104 } 105 *str = byte; 106 str++; 107 } while (more); 108 *nbytes = (int)(str - space); 109 return DW_DLV_OK; 110 } 111