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
_dwarf_pro_encode_leb128_nm(Dwarf_Unsigned val,int * nbytes,char * space,int splen)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
_dwarf_pro_encode_signed_leb128_nm(Dwarf_Signed value,int * nbytes,char * space,int splen)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