/*
 * AUTHOR
 * N. Nielsen
 *
 * LICENSE
 * This software is in the public domain.
 *
 * The software is provided "as is", without warranty of any kind,
 * express or implied, including but not limited to the warranties
 * of merchantability, fitness for a particular purpose, and
 * noninfringement. In no event shall the author(s) be liable for any
 * claim, damages, or other liability, whether in an action of
 * contract, tort, or otherwise, arising from, out of, or in connection
 * with the software or the use or other dealings in the software.
 *
 * SUPPORT
 * Send bug reports to: <nielsen@memberwebs.com>
 */

#ifndef __RLIB_H__
#define __RLIB_H__

#ifdef __cplusplus
extern "C" {
#endif

struct internal_state;
struct r_stream;

typedef unsigned char r_byte;
typedef unsigned int r_uint;


/*
 * r_replace:
 *  Represents a replacement which was found. This structure is passed
 *  to the r_match matching callback function below.
 */
typedef struct _r_replace
{
	r_uint offset;	/* The offset from the beginning of the file */
	r_uint from;	/* The offset from the beginning of the current buffer */
	r_uint flen;	/* The length of the data to be replaced */
	r_byte* to;		/* The data to replace */
	r_uint tlen;	/* The length of the replacement data */
}
r_replace;




/*
 * r_match
 *  Callback function which receives replacements made by the script.
 *
 *  stream:		rlib stream
 *  replace:	The replacement.
 *
 *  return 1 to accept this match, or 0 to skip.
 */
typedef int (*r_match)(struct r_stream* stream, r_replace* replace);

/*
 * r_write
 *  Callback used by the rlibRun output processed data.
 *
 *  stream:		rlib stream
 *  data:		The data
 *  len:		The number of bytes to write from data.
 */
typedef int (*r_write)(struct r_stream* stream, r_byte* data, r_uint len);

/*
 * r_message
 *  Callback which is sent messages from the 'message' command
 *  in a rep script.
 *
 *  stream:		rlib stream
 *  message:	Null terminated message
 */
typedef void (*r_message)(struct r_stream* stream, const char* message);






/*
 * r_stream
 *  The basic data interface into rlib.
 */
typedef struct r_stream
{
	/* ------ Data you supply -------------- */
	r_byte* nextIn;		/* The next byte to be read by rlib */
	r_uint availIn;		/* The number of bytes at nextIn */

	r_write fWrite;		/* Callback used for output */
	r_match fMatch;		/* Callback for confirmation or matching */
	r_message fMessage;	/* Callback for messages from script */
	void* arg;			/* Optional data for the above functions */

	/* -------- Data returned -------------- */
	r_uint total;		/* Total replaces */

	/* -------- Internal ------------------- */
	struct internal_state* state;
}
r_stream;





/*
 * r_script
 *  Represents a loaded rep script along with syntax error
 *  information.
 */
typedef struct _r_script
{
	r_byte* ops;		/* Compiled script */
	r_uint len;			/* The length of the script */
	char* error;		/* Syntax error details */
	r_uint errline;		/* Line number of syntax error */
}
r_script;





/*
 * rlibCompile
 *  Call this function to compile a script. It will be compiled into the
 *  r_sript structure. Be sure to zero the script structure passed.
 *
 *  script:		rlib script
 *  data:		rep script text. Must be null terminated.
 */
int rlibCompile(r_script* script, const char* data);



/*
 * rlibDump
 *  Write out byte codes for a script
 *
 *  script:		rlib script
 *  f:			Output stream to write to
 */
void rlibDump(r_script* script, FILE* f);



/*
 * rlibFree
 *  Free internal variables associated with this stream and/or
 *  script structure.
 *
 *  stream:		rlib stream
 *  script:		rlib script
 */
void rlibFree(r_stream* stream, r_script* script);



/*
 * rlibInit
 *  Call this function to initialize a rlib stream.
 *  For any of the following functions to work a stream must have been
 *  initialized.
 *
 *  stream:		Pointer to a zero'd stream structure.
 *  options:	Can be any combination of the following mode values.
 */
int rlibInit(r_stream* stream, long options);

/* Causes rlib to only output replacing text */
#define RLIB_MODE_PARSER	0x00000100

/* Causes rlib not to output anything */
#define RLIB_MODE_MATCHER	0x00000200



/*
 * rlibSetVar
 *  Set a variable for use in the script.
 *
 *  stream:		rlib stream
 *  var:		Variable name
 *  val:		Variable value
 */
int rlibSetVar(r_stream* stream, const char* var, const char* val);



/*
 * rlibRun
 *  Run the script. rlibRun will only "eat" nextIn upto where the
 *  last replace was found or up half whichever is more. Unless
 *  it's the last buffer in which case it finishes up.
 *
 *  stream:		rlib stream
 *  script:		rlib script
 *  done:		flag whether this is the last buffer
 */
int rlibRun(r_stream* stream, r_script* script, int done);



/* rlibClear: -----------------------------------------------------------
 *  Prepare and cleanup a context/stream after being run for a second
 *  run.
 *
 *  stream:		rlib context/stream
 */
void rlibClear(r_stream* stream);





/* ERROR CODES */

/* OK */
#define R_OK		0

/* Need more input */
#define R_IN		1

/* Finished processing script */
#define R_DONE		3

/* Not enough memory */
#define R_NOMEM		-1

/* Syntax error in the script */
#define R_SYNTAX	-2

/* Regular expression error in the script */
#define R_REGEXP	-3

/* Enless loop encountered */
#define R_LOOP		-4

/* User defined error from script */
#define R_USER		-5

/* Read or write error */
#define R_IOERR		-6

/* Invalid argument or stream data member */
#define R_INVARG	-10

#ifdef __cplusplus
}
#endif

#endif /* __RLIB_H__ */