env.c

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#include "str.h"
#include "alloc.h"
#include "env.h"
 
extern /*@null@*/char *env_get(char *s) 
{
  int i;
  unsigned int len;
 
  if (!s) return 0;
  len = str_len(s);
  for (i = 0; environ[i]; ++i)
    if (str_start(environ[i],s) && (environ[i][len] == '='))
      return environ[i] + len + 1;
  return 0;
}
 
extern char *env_findeq(char *s) 
{
  for (; *s; ++s)
    if (*s == '=') return s;
  return 0;
}
 
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_del(int i) {
  alloc_free(environ[i]);
  environ[i] = environ[--en];
  environ[en] = 0;
}
 
static void env_unsetlen(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_del(i);
}
 
int env_unset(char *s)
{
  if (!env_isinit) 
    if (!env_init()) return 0;
  env_unsetlen(s,str_len(s));
  return 1;
}
 
int env_set(char *s) 
{
  char *t;
 
  t = env_findeq(s);
  if (t) env_unsetlen(s,t - s);
  if (en == ea) {
    ea += 30;
    if (!alloc_re((void **)&environ,(en + 1) * sizeof(char *),(ea + 1) * sizeof(char *)))
      { ea = en; return 0; }
  }
  environ[en++] = s;
  environ[en] = 0;
  return 1;
}
 
int env_puts(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_set(u)) { alloc_free(u); return 0; }
  return 1;
}
 
int env_put(char *name,char *value) {
  char *ln;
  int len;
 
  if (!env_isinit) 
    if (!env_init()) return 0;
  len = str_len(name);
  ln = alloc(len + str_len(value) + 2);
  if (!ln) return 0;
  str_copy(ln,name);
  ln[len] = '=';
  str_copy(ln + len + 1,value);
  if (!env_set(ln)) { alloc_free(ln); 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;
}
 
static char *null = 0;
 
void env_clear() {
  if (env_isinit) 
    while (en) env_del(0);
  else environ = &null;
}
extern char *env_pick() 
{ 
  return environ[0]; 
}