#include <stdio.h>
#include <ctype.h>
#include "make.h"

static char *stripwh ();

/*
 * Get next token from the string.  Return a pointer to it, or NULL.
 * Adjust pointer to point to next part of string.
 * The string is modified.
 * A token consists of any number of non-white characters.
 */

char *token (strpp)
char **strpp;
{
    register char *s;
    register char *beg = NULL;

    DBUG_ENTER ("token");
    DBUG_3 ("tok", "get next token from '%s'", *strpp);
    (void) stripwh (strpp);
    if (**strpp) {
       beg = s = *strpp;
       while (*s && !isspace (*s)) {
           ++s;
       }
       if (*s) {
           *s++ = '\0';
       }
       *strpp = s;
       DBUG_3 ("tok", "found token '%s'", beg);
    }
    DBUG_RETURN (beg);
}


/*
 * Parse character escape-sequences in a line of text.
 *     <EscChar><EscChar> = <EscChar>
 *     <EscChar>n = newline, and so on
 *     <EscChar><char> = <char>
 * The string is truncated at the first non-escaped occurance of 'comchar'.
 */

void escape (str, comchar)
char *str;
char comchar;
{
    register char *d;
    register char c;

    DBUG_ENTER ("escape");
    for (d = str; *str && *str != comchar; ++str) {
       if (*str == ESCCHAR && *(str + 1)) {
           switch ((c = *++str)) {
               case ESCCHAR: 
                   *d++ = ESCCHAR;
                   break;
               case 'n': 
                   *d++ = '\n';
                   break;
               case 'r': 
                   *d++ = '\r';
                   break;
               case 't': 
                   *d++ = '\t';
                   break;
               case 'b': 
                   *d++ = '\b';
                   break;
               case 'f': 
                   *d++ = '\f';
                   break;
               default: 
                   *d++ = c;
                   break;
           }
       } else {
           *d++ = *str;
       }
    }
    *d++ = 0;
    DBUG_VOID_RETURN;
}

static char *stripwh (strpp)
char **strpp;
{
    register char *s;

    s = *strpp;
    while (isspace (*s)) {
       ++s;
    }
    return (*strpp = s);
}