diff options
Diffstat (limited to 'string/envz.c')
| -rw-r--r-- | string/envz.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/string/envz.c b/string/envz.c new file mode 100644 index 0000000000..4d0816e4e1 --- /dev/null +++ b/string/envz.c @@ -0,0 +1,171 @@ +/* Routines for dealing with '\0' separated environment vectors + + Copyright (C) 1995, 1996 Free Software Foundation, Inc. + + Written by Miles Bader <miles@gnu.ai.mit.edu> + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2, or (at + your option) any later version. + + This program 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 + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ + +#include <malloc.h> +#include <string.h> + +#include "envz.h" + +/* The character separating names from values in an envz. */ +#define SEP '=' + +/* Returns a pointer to the entry in ENVZ for NAME, or 0 if there is none. + If NAME contains the separator character, only the portion before it is + used in the comparison. */ +char * +envz_entry (char *envz, unsigned envz_len, char *name) +{ + while (envz_len) + { + char *p = name; + char *entry = envz; /* Start of this entry. */ + + /* See how far NAME and ENTRY match. */ + while (envz_len && *p == *envz && *p && *p != SEP) + p++, envz++, envz_len--; + + if ((*envz == '\0' || *envz == SEP) && (*p == '\0' || *p == SEP)) + /* Bingo! */ + return entry; + + /* No match, skip to the next entry. */ + while (envz_len && *envz) + envz++, envz_len--; + if (envz_len) + envz++, envz_len--; /* skip '\0' */ + } + + return 0; +} + +/* Returns a pointer to the value portion of the entry in ENVZ for NAME, or 0 + if there is none. */ +char * +envz_get (char *envz, unsigned envz_len, char *name) +{ + char *entry = envz_entry (envz, envz_len, name); + if (entry) + { + while (*entry && *entry != SEP) + entry++; + if (*entry) + entry++; + else + entry = 0; /* A null entry. */ + } + return entry; +} + +/* Remove the entry for NAME from ENVZ & ENVZ_LEN, if any. */ +void +envz_remove (char **envz, unsigned *envz_len, char *name) +{ + char *entry = envz_entry (*envz, *envz_len, name); + if (entry) + argz_delete (envz, envz_len, entry); +} + +/* Adds an entry for NAME with value VALUE to ENVZ & ENVZ_LEN. If an entry + with the same name already exists in ENVZ, it is removed. If VALUE is + NULL, then the new entry will a special null one, for which envz_get will + return NULL, although envz_entry will still return an entry; this is handy + because when merging with another envz, the null entry can override an + entry in the other one. Null entries can be removed with envz_strip (). */ +error_t +envz_add (char **envz, unsigned *envz_len, char *name, char *value) +{ + envz_remove (envz, envz_len, name); + + if (value) + /* Add the new value, if there is one. */ + { + unsigned name_len = strlen (name); + unsigned value_len = strlen (value); + unsigned old_envz_len = *envz_len; + unsigned new_envz_len = old_envz_len + name_len + 1 + value_len + 1; + char *new_envz = realloc (*envz, new_envz_len); + + if (new_envz) + { + bcopy (name, new_envz + old_envz_len, name_len); + new_envz[old_envz_len + name_len] = SEP; + bcopy (value, new_envz + old_envz_len + name_len + 1, value_len); + new_envz[new_envz_len - 1] = 0; + + *envz = new_envz; + *envz_len = new_envz_len; + + return 0; + } + else + return ENOMEM; + } + else + /* Add a null entry. */ + return argz_add (envz, envz_len, name); +} + +/* Adds each entry in ENVZ2 to ENVZ & ENVZ_LEN, as if with envz_add(). If + OVERRIDE is true, then values in ENVZ2 will supercede those with the same + name in ENV, otherwise not. */ +error_t +envz_merge (char **envz, unsigned *envz_len, char *envz2, unsigned envz2_len, + int override) +{ + error_t err = 0; + + while (envz2_len && ! err) + { + char *old = envz_entry (*envz, *envz_len, envz2); + size_t new_len = strlen (envz2) + 1; + + if (! old) + err = argz_append (envz, envz_len, envz2, new_len); + else if (override) + { + argz_delete (envz, envz_len, old); + err = argz_append (envz, envz_len, envz2, new_len); + } + + envz2 += new_len; + envz2_len -= new_len; + } + + return err; +} + +/* Remove null entries. */ +void +envz_strip (char **envz, unsigned *envz_len) +{ + char *entry = *envz; + unsigned left = *envz_len; + while (left) + { + unsigned entry_len = strlen (entry) + 1; + left -= entry_len; + if (! index (entry, SEP)) + /* Null entry. */ + bcopy (entry, entry + entry_len, left); + else + entry += entry_len; + } + *envz_len = entry - *envz; +} |