Escape and Unescape Illegal Characters in URIs

/*
**	(c) COPYRIGHT MIT 1995.
**	Please first read the full copyright statement in the file COPYRIGH.
*/
This module have been spawned from HTParse, as it then can be used in utility programs without loading a whole bunch of the library code. It contains functions for escaping and unescaping a URI for reserved characters in URIs.

This module is implemented by HTEscape.c, and it is a part of the W3C Reference Library.

#ifndef HTESCAPE_H
#define HTESCAPE_H

Encode Unacceptable Characters using %xy

This funtion takes a string containing any sequence of ASCII characters, and returns a malloced string containing the same infromation but with all "unacceptable" characters represented in the form %xy where x and y are two hex digits.
typedef enum _HTURIEncoding {
    URL_XALPHAS		= 0x1,
    URL_XPALPHAS	= 0x2,
    URL_PATH		= 0x4
} HTURIEncoding;

extern char * HTEscape (CONST char * str, HTURIEncoding mask);

Decode %xy Escaped Characters

This function takes a pointer to a string in which character smay have been encoded in %xy form, where xy is the acsii hex code for character 16x+y. The string is converted in place, as it will never grow.
extern char * HTUnEscape (char * str);
#endif	/* HTESCAPE_H */
End of HTEscape Module