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/* env.c, envread.c, env.h: environ library
Daniel J. Bernstein, djb@silverton.berkeley.edu.
Depends on str.h, alloc.h.
Requires environ.
19960113: rewrite. warning: interface is different.
No known patent problems.
*/
#include "str.h"
#include "alloc.h"
#include "env.h"
int env_isinit = 0; /* if env_isinit: */
static int ea; /* environ is a pointer to ea+1 char*'s. */
static int en; /* the first en of those are ALLOCATED. environ[en] is 0. */
static void env_goodbye(i) int i;
{
alloc_free(environ[i]);
environ[i] = environ[--en];
environ[en] = 0;
}
static char *null = 0;
void env_clear()
{
if (env_isinit) while (en) env_goodbye(0);
else environ = &null;
}
static void env_unsetlen(s,len) char *s; int len;
{
int i;
for (i = en - 1;i >= 0;--i)
if (!str_diffn(s,environ[i],len))
if (environ[i][len] == '=')
env_goodbye(i);
}
int env_unset(s) char *s;
{
if (!env_isinit) if (!env_init()) return 0;
env_unsetlen(s,str_len(s));
return 1;
}
static int env_add(s) char *s;
{
char *t;
t = env_findeq(s);
if (t) env_unsetlen(s,t - s);
if (en == ea)
{
ea += 30;
if (!alloc_re(&environ,(en + 1) * sizeof(char *),(ea + 1) * sizeof(char *)))
{ ea = en; return 0; }
}
environ[en++] = s;
environ[en] = 0;
return 1;
}
int env_put(s) char *s;
{
char *u;
if (!env_isinit) if (!env_init()) return 0;
u = alloc(str_len(s) + 1);
if (!u) return 0;
str_copy(u,s);
if (!env_add(u)) { alloc_free(u); return 0; }
return 1;
}
int env_put2(s,t) char *s; char *t;
{
char *u;
int slen;
if (!env_isinit) if (!env_init()) return 0;
slen = str_len(s);
u = alloc(slen + str_len(t) + 2);
if (!u) return 0;
str_copy(u,s);
u[slen] = '=';
str_copy(u + slen + 1,t);
if (!env_add(u)) { alloc_free(u); return 0; }
return 1;
}
int env_init()
{
char **newenviron;
int i;
for (en = 0;environ[en];++en) ;
ea = en + 10;
newenviron = (char **) alloc((ea + 1) * sizeof(char *));
if (!newenviron) return 0;
for (en = 0;environ[en];++en)
{
newenviron[en] = alloc(str_len(environ[en]) + 1);
if (!newenviron[en])
{
for (i = 0;i < en;++i) alloc_free(newenviron[i]);
alloc_free(newenviron);
return 0;
}
str_copy(newenviron[en],environ[en]);
}
newenviron[en] = 0;
environ = newenviron;
env_isinit = 1;
return 1;
}
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