Programmer 7500/MAX_PROGRAMMERS.iso/INFO/C/ELEMC.ZIP/STRINGS.C

C/C++ Source or Header | 1985-05-09 | 10.5 KB | 299 lines

#include <stdio.h>

#include <ctype.h>



/*

;;      file:   _STRING.C

;;

;; --------------- Command Tail Processing Functions ---------------

;;

;;      This next set of functions are meant to be used together. Examples

;;on their use follows.

;;

;;

;;int num_args(string)  Returns the number of args in the string, seperated

;;                      by delims (see delim(), below). Leading delimiters

;;                      are ignored.

;;

;;char *next_arg(string)        Returns a pointer to the next arg, delimited

;;                      by a delim, skipping over the current arg. Use via

;;                      ptr= nextarg(ptr) to skip to each argument. All

;;                      switches at the end of the current arg are skipped.

;;

;;

;;char *skip_delim(string) Skips leading delims in a string. returns a pointer.

;;

;;cpyarg(to,from)               Copies a string, up to the next delim or switch.

;;                      Leading and trailing delimiters are stripped (from

;;                      the output string) and a null terminator is added.

;;

;;                      after cpyarg()          FROM: foo/b

;;                                              TO: foo

;;

;;delim(c)              Returns true if the character is a delimiter.

;;                      Nulls are not considered a delimiter. The list of

;;                      delimiters is contained in the array '_dlmlst', and

;;                      can be changed via newdelim().

;;

;;newdelim(s)           Replace the list of delimiters. The string 's' must

;;                      be less than 20 chars.

;;

;;isswitch(c)           Returns true if the character is the current DOS

;;                      switch character.

;;

;;char filtchar(c)      Convert a character to one legal for an MSDOS filename.

;;                      Illegal characters such as switch or path seperators,

;;                      control characters, etc are changed to '$'. Bit 7 is

;;                      masked off. (Disallows foreign language support??)

;;

;;wild(string)          Returns true if the string contains a star or question.

;;

;;char *strip_path(out,in) Copies the disk specifier or pathname to the output

;;                      array, and returns a pointer to the name in the input

;;                      string. Drive specs are considered a path, and are

;;                      treated as such by DOS. Stripping "a:foo" and

;;                      "bin/foo/framis.asm" result in:

;;

;;                              IN:     "A:"

;;                              IN:     "bin\foo"

;;

;;                              OUT:    "A:"

;;                              OUT:    "bin\"

;;

;;strip_switch(out,in)  Copy the switches from the in string, remove the switch

;;                      character and put all the characters in the out array.

;;                      Each is converted to upper case, and the string is null

;;                      terminated.

;;

;;ispath_delim(c)       Returns true if the character is a legal pathname

;;char c;               component seperator. The only two characters legal

;;                      (here at least) are \ and-or /. For example:

;;

;;                      Switch character = /

;;                              ispath_delim('/') == 0

;;                              ispath_delim('\\') == 1

;;                      Switch character = -

;;                              ispath_delim('/') == 1

;;                              ispath_delim('\\') == 1

;;                      Switch character = \

;;                              ispath_delim('/') == 1

;;                              ispath_delim('\\') == 0

;;

;;

;; --------- Command Tail Processing Examples ----------

;;

;;      This is an example of one way to use the above functions to process

;;an MSDOS program command tail. You do not need to know what the system switch

;;character or legal path seperators are. If you can't handle paths, strip them

;;off. Assume there is a pointer, p, that points to a command tail string:

;;

;;      p= "  source.ext abc.asm/v+\bin\def.com /x/y/z"

;;

;;      p= skip_delim(p);               /* p= "source.exe abc...... */

;;

;;      p= next_arg(p);                 /* p= "abc.asm/v.... "  */

;;      cpyarg(work,p);                 /* work= "abc.asm"  */

;;      s= strip_path(work,p));         /* s= "abc.asm"   path= ""  */

;;      strip_switch(sw,p);             /* sw= "V"  */

;;

;;      p= next_arg(p);                 /* p= "\bin\def.com"  */

;;      cpyarg(work,p);                 /* work= "\bin\def.com"  */

;;      s= strip_path(path,p);          /* s= "def.com"  path= "\bin\"  */

;;      strip_switch(sw,p);             /* sw= ""  */

;;

;;      p= next_arg(p);                 /* p= "/x/y/z"  */

;;      cpyarg(work,p);                 /* work= ""  */

;;      s= strip_path(path,p);          /* s= ""  path= ""  */

;;      strip_switch(sw,p);             /* sw= "XYZ"  */

;;

;;      p= next_arg(p);                 /* p= ""  */

;;

;;      while (num_args(p)              /* while not end of string ... */

;;      while (*p)                      /* another way ... */

;;

;;

;;char *name,sw[4],path[40];

;;

;;      p= skip_delim(p);

;;      while (num_args(p) > 0) {       /* *p points to the current arg, */

;;              name= strip_path(path,p);

;;              strip_switch(sw,p);

;;              printf("Path= %s, Name= %s, Switches= %s\n",path,name,sw);

;;      }

;;

*/

/* Return the number of args left in the string. */



num_args(string)

char *string;

{

int count;



        count= 0;

        string= (char *)skip_delim(string);     /* skip leading blanks, */

        while (*string) {

                ++count;                        /* count one, */

                string= (char *)next_arg(string); /* find next, */

        }

        return(count);

}

/* Return a pointer to the next argument in the string. */



next_arg(string)

char *string;

{

        while ((!delim(*string)) && *string)            /* skip this one, */

                ++string;                               /* up to delim, */

        string= (char *)skip_delim(string);             /* then skip delims, */

        return(string);

}



/* Skip over the leading delimiters in a string. */



skip_delim(string)

char *string;

{

        while (delim(*string) && *string)

                ++string;

        return(string);

}

/* Copy the string to the destination array, stopping if we find one

of our delimiters or switches. */



cpyarg(to,from)

char *to;

char *from;

{

        while ( (!delim(*from)) && (!isswitch(*from)) && *from)

                *to++= *from++;

        *to= '\0';

        return;

}

/* Strip any switches from the input string, put into the output array. */



strip_switch(out,in)

char *out;

char *in;

{

        while (*in && (!isswitch(*in)))         /* skip to end of string */

                ++in;                           /* or first switch, */



        while (*in && isswitch(*in)) {          /* copy switch args while */

                ++in;

                *out++ = toupper(*in);          /* stripping switch chars, */

                ++in;

        }

        *out= '\0';                             /* terminate it, */

        return;

}

/* ----- List of legal delimiters. This is the default list ----- */



char _dlmlst[20] = { " \t,+" }; /* space, tab, comma, plus */



/* Change the list of delimiters. */



newdelim(s)

char *s;

{

        strcpy(_dlmlst,s);

        return;

}



/* Return true if the character is a delimiter from the list above. */



delim(c)

char c;

{

int i;

        for (i= 0; _dlmlst[i]; ++i) {

                if (c == _dlmlst[i]) return(1);

        }

        return(0);

}

/* return true if the character is the current switch character. */



isswitch(c)

char c;

{

        return(c == _charop(0,0));

}

/* Clean up the character for a legal MSDOS filename. Convert undesireable

characters to a dollar. */



char filtchar(c)

char c;

{

        c&= 0x7f;                       /* strip bit 7, */

        if (isswitch(c) || ispath_delim(c) || (c < ' ') || (c > '~') )

                c= '$';                 /* dont allow illegal chars */

        c= toupper(c);                  /* all uppercase, */

        return(c);

}

/* Return 1 if the string is a wild filespec. */



wild(string)

char *string;

{

char *p;



        p= string;

        while (*p) {

                if (*p == '?')

                        return(1);

                if (*p == '*')

                        return(1);

                ++p;

        }

        return(0);                              /* not wild. */

}

/* Strip the pathname or disk specifier from a filename, return it in a

seperate array. We do this by initially copying the entire name in, then

searching for the colon or slash. Right after the last one we find,

stuff a null, removing the name part.



Also return a pointer to the name part in the input name. */



strip_path(out,in)

char *out;

char *in;

{

char *name;

char *endpath;



        strcpy(out,in);                 /* duplicate, for working, */

        name= in;                       /* point to name, */

        endpath= out;                   /* and end of path part, */



        while (*in) {                   /* look for slashes or colons, */

                if (*in == ':') {       /* if a colon, */

                        endpath= ++out; /* point to name, */

                        name= ++in;

                } else if (ispath_delim(*in)) {

                        endpath= ++out; /* move the pointer up, */

                        name= ++in;

                } else {

                        ++in;

                        ++out;

                }

        }

        *endpath= '\0';                 /* delete the name part, */

        return(name);                   /* return ptr to name part. */

}



/* Return true if the character is a legal path name component seperator.

The legal ones here are \ or /, depending on what the switch character is. */



ispath_delim(c)

char c;

{

        if ((c == '\\') && (!isswitch('\\'))) return(1);

        if ((c == '/') && (!isswitch('/'))) return(1);

        return(0);

}



4% ') && (!isswitch('\\'))) return(1);

        if ((c == '/') && (!isswitch('/'))) return(1);

        return(0