/****************************************************************************/
/*                                                                          */
/* Module:     getopt.c - Scan environment area for matching string         */
/*                                                                          */
/* Programmer: David Beckemeyer, with modifications by George R. Woodside   */
/*                                                                          */
/* Date:       January 7, 1987                                              */
/*                                                                          */
/* Function:   Search the environment area for a named environment string.  */
/*             Return a null if string is not found.                        */
/*             Return a pointer to the associated environment variable if   */
/*             the input string is found.                                   */
/*                                                                          */
/****************************************************************************/

#include <basepage.h>

char *getenv(ustring)                   /* note that return is a char *     */
char *ustring;
{
  char *temp;
  char *user;
  struct b_page *bpage;                 /* Basepage pointer                 */

  bpage = _base;                        /* assign the basepage pointer      */
  temp=(char *)(bpage->p_env);          /* pointer to environment strings   */

  while ((*temp)!=0)                    /* while there are strings to check */
    {
      user=ustring;                     /* load start of user's string      */
      while((*temp)==(*user))           /* while the characters match,      */
        {
          temp++;                       /* move environment up              */
          user++;                       /* and user string up               */
        }                               /* end bytes match                  */

      /**********************************************************************/
      /* If the environment string is now at "=", and the user string is    */
      /* at it's end, then we have a match.                                 */
      /**********************************************************************/

      if ((*temp) == '=' && (*user) == 0) /* if it matched,                 */
        {
          if (*(++temp)==0)             /* and next byte is null,           */
            temp++;                     /* point to next value              */
          return temp;                  /* and return that                  */
        }

      if ((*temp)!=0)                   /* if environment string not ended  */
        {
          while ((*(temp++))!=0);       /* skip to the end                  */
        }
      else                              /* otherwise,                       */
        temp++;                         /* move to next string              */
    }
    return(0);                          /* if we get here, no matches       */
}