Update.
[glibc.git] / string / envz.c
blob535f42e8647b57ff58d51999ef8dbf414359eb44
1 /* Routines for dealing with '\0' separated environment vectors
2 Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Written by Miles Bader <miles@gnu.ai.mit.edu>
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Library General Public License as
8 published by the Free Software Foundation; either version 2 of the
9 License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Library General Public License for more details.
16 You should have received a copy of the GNU Library General Public
17 License along with the GNU C Library; see the file COPYING.LIB. If not,
18 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 #include <malloc.h>
22 #include <string.h>
24 #include "envz.h"
26 /* The character separating names from values in an envz. */
27 #define SEP '='
29 /* Returns a pointer to the entry in ENVZ for NAME, or 0 if there is none.
30 If NAME contains the separator character, only the portion before it is
31 used in the comparison. */
32 char *
33 envz_entry (const char *envz, size_t envz_len, const char *name)
35 while (envz_len)
37 const char *p = name;
38 const char *entry = envz; /* Start of this entry. */
40 /* See how far NAME and ENTRY match. */
41 while (envz_len && *p == *envz && *p && *p != SEP)
42 p++, envz++, envz_len--;
44 if ((*envz == '\0' || *envz == SEP) && (*p == '\0' || *p == SEP))
45 /* Bingo! */
46 return (char *) entry;
48 /* No match, skip to the next entry. */
49 while (envz_len && *envz)
50 envz++, envz_len--;
51 if (envz_len)
52 envz++, envz_len--; /* skip '\0' */
55 return 0;
58 /* Returns a pointer to the value portion of the entry in ENVZ for NAME, or 0
59 if there is none. */
60 char *
61 envz_get (const char *envz, size_t envz_len, const char *name)
63 char *entry = envz_entry (envz, envz_len, name);
64 if (entry)
66 while (*entry && *entry != SEP)
67 entry++;
68 if (*entry)
69 entry++;
70 else
71 entry = 0; /* A null entry. */
73 return entry;
76 /* Remove the entry for NAME from ENVZ & ENVZ_LEN, if any. */
77 void
78 envz_remove (char **envz, size_t *envz_len, const char *name)
80 char *entry = envz_entry (*envz, *envz_len, name);
81 if (entry)
82 argz_delete (envz, envz_len, entry);
85 /* Adds an entry for NAME with value VALUE to ENVZ & ENVZ_LEN. If an entry
86 with the same name already exists in ENVZ, it is removed. If VALUE is
87 NULL, then the new entry will a special null one, for which envz_get will
88 return NULL, although envz_entry will still return an entry; this is handy
89 because when merging with another envz, the null entry can override an
90 entry in the other one. Null entries can be removed with envz_strip (). */
91 error_t
92 envz_add (char **envz, size_t *envz_len, const char *name, const char *value)
94 envz_remove (envz, envz_len, name);
96 if (value)
97 /* Add the new value, if there is one. */
99 size_t name_len = strlen (name);
100 size_t value_len = strlen (value);
101 size_t old_envz_len = *envz_len;
102 size_t new_envz_len = old_envz_len + name_len + 1 + value_len + 1;
103 char *new_envz = realloc (*envz, new_envz_len);
105 if (new_envz)
107 bcopy (name, new_envz + old_envz_len, name_len);
108 new_envz[old_envz_len + name_len] = SEP;
109 bcopy (value, new_envz + old_envz_len + name_len + 1, value_len);
110 new_envz[new_envz_len - 1] = 0;
112 *envz = new_envz;
113 *envz_len = new_envz_len;
115 return 0;
117 else
118 return ENOMEM;
120 else
121 /* Add a null entry. */
122 return argz_add (envz, envz_len, name);
125 /* Adds each entry in ENVZ2 to ENVZ & ENVZ_LEN, as if with envz_add(). If
126 OVERRIDE is true, then values in ENVZ2 will supersede those with the same
127 name in ENV, otherwise not. */
128 error_t
129 envz_merge (char **envz, size_t *envz_len, const char *envz2,
130 size_t envz2_len, int override)
132 error_t err = 0;
134 while (envz2_len && ! err)
136 char *old = envz_entry (*envz, *envz_len, envz2);
137 size_t new_len = strlen (envz2) + 1;
139 if (! old)
140 err = argz_append (envz, envz_len, envz2, new_len);
141 else if (override)
143 argz_delete (envz, envz_len, old);
144 err = argz_append (envz, envz_len, envz2, new_len);
147 envz2 += new_len;
148 envz2_len -= new_len;
151 return err;
154 /* Remove null entries. */
155 void
156 envz_strip (char **envz, size_t *envz_len)
158 char *entry = *envz;
159 size_t left = *envz_len;
160 while (left)
162 size_t entry_len = strlen (entry) + 1;
163 left -= entry_len;
164 if (! index (entry, SEP))
165 /* Null entry. */
166 bcopy (entry, entry + entry_len, left);
167 else
168 entry += entry_len;
170 *envz_len = entry - *envz;