1 /* 2 3 Copyright (C) 2000,2004 Silicon Graphics, Inc. All Rights Reserved. 4 5 This program is free software; you can redistribute it and/or modify it 6 under the terms of version 2.1 of the GNU Lesser General Public License 7 as published by the Free Software Foundation. 8 9 This program is distributed in the hope that it would be useful, but 10 WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 12 13 Further, this software is distributed without any warranty that it is 14 free of the rightful claim of any third person regarding infringement 15 or the like. Any license provided herein, whether implied or 16 otherwise, applies only to this software file. Patent licenses, if 17 any, provided herein do not apply to combinations of this program with 18 other software, or any other product whatsoever. 19 20 You should have received a copy of the GNU Lesser General Public 21 License along with this program; if not, write the Free Software 22 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston MA 02110-1301, 23 USA. 24 25 Contact information: Silicon Graphics, Inc., 1500 Crittenden Lane, 26 Mountain View, CA 94043, or: 27 28 http://www.sgi.com 29 30 For further information regarding this notice, see: 31 32 http://oss.sgi.com/projects/GenInfo/NoticeExplan 33 34 */ 35 36 37 38 #include "config.h" 39 #include "libdwarfdefs.h" 40 #include <string.h> 41 #include "pro_incl.h" 42 43 #define MORE_BYTES 0x80 44 #define DATA_MASK 0x7f 45 #define DIGIT_WIDTH 7 46 #define SIGN_BIT 0x40 47 48 49 /*------------------------------------------------------------- 50 Encode val as a leb128. This encodes it as an unsigned 51 number. 52 ---------------------------------------------------------------*/ 53 /* return DW_DLV_ERROR or DW_DLV_OK. 54 ** space to write leb number is provided by caller, with caller 55 ** passing length. 56 ** number of bytes used returned thru nbytes arg 57 */ 58 int 59 _dwarf_pro_encode_leb128_nm(Dwarf_Unsigned val, int *nbytes, 60 char *space, int splen) 61 { 62 char *a; 63 char *end = space + splen; 64 65 a = space; 66 do { 67 unsigned char uc; 68 69 if (a >= end) { 70 return DW_DLV_ERROR; 71 } 72 uc = val & DATA_MASK; 73 val >>= DIGIT_WIDTH; 74 if (val != 0) { 75 uc |= MORE_BYTES; 76 } 77 *a = uc; 78 a++; 79 } while (val); 80 *nbytes = a - space; 81 return DW_DLV_OK; 82 } 83 84 /* return DW_DLV_ERROR or DW_DLV_OK. 85 ** space to write leb number is provided by caller, with caller 86 ** passing length. 87 ** number of bytes used returned thru nbytes arg 88 ** encodes a signed number. 89 */ 90 int 91 _dwarf_pro_encode_signed_leb128_nm(Dwarf_Signed value, int *nbytes, 92 char *space, int splen) 93 { 94 char *str; 95 Dwarf_Signed sign = -(value < 0); 96 int more = 1; 97 char *end = space + splen; 98 99 str = space; 100 101 do { 102 unsigned char byte = value & DATA_MASK; 103 104 value >>= DIGIT_WIDTH; 105 106 if (str >= end) { 107 return DW_DLV_ERROR; 108 } 109 /* 110 * Remaining chunks would just contain the sign bit, and this chunk 111 * has already captured at least one sign bit. 112 */ 113 if (value == sign && ((byte & SIGN_BIT) == (sign & SIGN_BIT))) { 114 more = 0; 115 } else { 116 byte |= MORE_BYTES; 117 } 118 *str = byte; 119 str++; 120 } while (more); 121 *nbytes = str - space; 122 return DW_DLV_OK; 123 } 124