Subj : Tool wanted
To   : Angus Mcleod
From : Frank Reid
Date : Thu Dec 02 2004 06:59 am

  Re: Tool wanted
  By: Angus Mcleod to Frank Reid on Wed Dec 01 2004 11:02 pm

 >  > root@freebsd# urlencode 'Hello, World!'
 >  > Hello%2C%20World%21
 > 
 > Damn!  That's exactly what I need to do.  :-/

I cobbled this together based on some code I found on Google for the 
RFC-1738 stuff.  There are absolutely no bounds checking on the main 
routine, which only "encodes" the input string passed to the program.  
Maybe you can work something with this?

[root@new root]# ./urlcodec 'Hello, World!'
Hello%2C%20World%21
Hello, World!


/* $Id: $ */
/*
 * * Copyright(c) 2003, B. Augestad <b...@metasystems.no>
 * * COPYING RESTRICTIONS APPLY, see COPYING file.
 * *
 * * Implements encode and decode() functions for HTTP URL arguments
 * * according to RFC 1738.
 * *
 * * The short and simple rule is that if a character is A-Za-z0-9
 * * it is not encoded, anything else is encoded. The character is
 * * encoded as a two digit hex number, prefixed with %.
 * *
 * * Issues: This version decodes %00, which maps to '\0'.
 * * Don't know if that's a serious issue or not(security).
 * */


#include <stddef.h>
#include <errno.h>


/* Local helper
 * * Returns 1 on success, 0 on illegal input.
 * */
static int encode(int c, char *dest)
{
  int high, low;


  /* Don't encode illegal input */
  if (c < 0 || c > 255)
    return 0;


  high = (c & 0xf0) >> 4;
  low = (c & 0x0f);


  if (high > 9)
    high = 'A' + high - 10;
  else
    high = '0' + high;


  if (low > 9)
    low = 'A' + low - 10;
  else
    low = '0' + low;


  *dest++ = '%';
  *dest++ = high;
  *dest = low;
  return 1;

}


/* Local helper.
 *  * Accepts an alphanumeric character in the range [0-9a-fA-F]
 *  * and returns it converted to an integer in the range 0-15.
 *  */
static int hexchar2int(int c)
{
  if (c >= '0' && c <= '9')
    return c - '0';
  else
    if (c >= 'a' && c <= 'f')
    return 10 + c - 'a';
  else
    if (c >= 'A' && c <= 'F')
    return 10 + c - 'A';
  else                                      /* Illegal input. */
    return -1;


}


/* Local helper.
 * * Decodes an encoded character. Returns -1 on errors, else an
 * * integer which represents a decoded character. Note that hexchar2int
 * * will implicitly detect end of string ('\0').
 * */
static int decode(const char *src)
{
  int c1, c2;

  if (*src != '%')
    return -1;


  c1 = hexchar2int((unsigned char) *++src);
  if (c1 == -1)
    return -1;


  c2 = hexchar2int((unsigned char) *++src);
  if (c2 == -1)
    return -1;


  return (c1 << 4) + c2;

}


int clc_rfc1738_encode(char *dest, const char *src, size_t cb)
{

  if ((dest == NULL) || (src == NULL) || (cb <= 0))
    return 0;

  while (*src != '\0' && cb > 0) {


    /* No isalnum() due to locale */
    if ((*src >= 'A' && *src <= 'Z')
        || (*src >= 'a' && *src <= 'z')
        || (*src >= '0' && *src <= '9')) {
      *dest++ = *src++;
    } else
      if (cb > 2) {
      if (!encode((unsigned char) *src, dest)) {
        printf("\nInvalid Input String.\n");
        return 0;
      }
      dest += 3;
      cb -= 3;
      src++;
    }
    else {
      printf("\nOut of Room.\n");
      return 0;
    }
  }

  /* If we ran out of buffer space */
  if (*src != '\0') {
    printf("\nNo Buffer Available.");
    return 0;
  }
  *dest = '\0';
  return 1;



}


int clc_rfc1738_decode(char *dest, const char *src, size_t cb)
{
  int c;

  if ((src == NULL) || (dest == NULL))
    return 0;

  while (cb > 0 && *src != '\0') {
    if (*src == '%') {
      if ((c = decode(src)) == -1) {
        printf("\nInvalid Input String.\n");
        return 0;
      }
      *dest++ = c;
      src += 3;
    } else
      *dest++ = *src++;


    cb--;
  }


  if (cb == 0) {
    printf("\nNo Buffer Available.");
    return 0;
  }
  *dest = '\0';
  return 1;

}

main(int argc, char *argv[])
{
  char s[1024], s1[1024];

  strcpy(s1, argv[1]);

  clc_rfc1738_encode(s, s1, 1024);

  printf("%s\n", s);

  clc_rfc1738_decode(s1, s, 1024);

  printf("%s\n", s1);

  return 0;
}
 


---
 þ Synchronet þ Wireless Neighbors -- telnet://wirelessneighbors.net

.