/*                                                 W3C Sample Code Library libwww Chunk Class
                                     THE CHUNK CLASS
                                             
 */
/*
**      (c) COPYRIGHT MIT 1995.
**      Please first read the full copyright statement in the file COPYRIGH.
*/
/*

   The Chunk Class  defines a way to automatically handle dynamic strings and other data
   types. You create a chunk with an initial size and it will then automatically grow to
   accomodate added data to the chunk. It is a general utility module. It is garanteed
   that the array is '\0' terminated at all times (and hence is a valid C type string).
   The method HTChunkTerminate can be used to explicitly add a terminating '\0'and then to
   include this character in the chunk size. If left out, the terminating character is
   _not_ considered part of the chunk.
   
   _Note_: The names without a "_" (made as a #define's) are only provided for backwards
   compatibility and should not be used.
   
   This module is implemented by HTChunk.c, and it is a part of the W3C Sample Code
   Library.
   
 */
#ifndef HTCHUNK_H
#define HTCHUNK_H

/*

THE CHUNK CLASS

   This structure should not be referenced outside this module! We only keep it here to
   maintain high performance. _Don't _use it directly!
   
 */
typedef struct {
        int     size;           /* In bytes                     */
        int     growby;         /* Allocation unit in bytes     */
        int     allocated;      /* Current size of *data        */
        char *  data;           /* Pointer to malloced area or 0 */
} HTChunk;
/*

CREATE NEW CHUNK

   Create a new chunk and specify the number of bytes to allocate at a time when the chunk
   is later extended. Arbitrary but normally a trade-off time vs. memory
   
 */
#define HTChunkCreate(growby) HTChunk_new(growby)
extern HTChunk * HTChunk_new (int growby);
/*

FREE A CHUNK

   Free a chunk created by HTChunkCreatefrom memory
   
 */
#define HTChunkFree(ch) HTChunk_delete(ch)
extern void HTChunk_delete (HTChunk * ch);
/*

CLEAR A CHUNK

   Keep the chunk in memory but clear all data kept inside. This can be used if you know
   that you can reuse the allocated memory instead of allocating new memory.
   
 */
#define HTChunkClear(ch) HTChunk_clear(ch)
extern void HTChunk_clear (HTChunk * ch);
/*

ENSURE A CHUNK HAS A CERTAIN AMOUNT OF FREE SPACE

   Make sure that a chunk has a certain size. If this is not the case then the chunk is
   expanded. Nothing is done if the current size if bigger than the size requested.
   
 */
#define HTChunkEnsure(ch, s) HTChunk_ensure(ch, s)
extern void HTChunk_ensure (HTChunk * ch, int s);
/*

APPEND A CHARACTER TO A CHUNK

   Add the character and increment the size of the chunk by one character
   
 */
#define HTChunkPutc(ch, c) HTChunk_putc(ch, c)
extern void HTChunk_putc (HTChunk * ch, char c);
/*

APPEND A STRING TO A CHUNK

   Add the string and increment the size of the chunk by the length of the string (without
   the trailing zero)
   
 */
#define HTChunkPuts(ch, str) HTChunk_puts(ch, str)
extern void HTChunk_puts (HTChunk * ch, const char *str);
/*

APPEND A BLOCK TO A CHUNK

   Add the block and increment the size of the chunk by the len
   
 */
extern void HTChunk_putb (HTChunk * ch, const char *block, int len);

/*

ZERO TERMINATE A CHUNK

   As a chunk often is a dynamic string, it needs to be terminated by a zero in order to
   be used in C. However, _by default_ any chunk is _always_ zero terminated, so the only
   purpose of this function is to increment the size counter with one corresponding to the
   zero.
   
 */
#define HTChunkTerminate(ch)    HTChunk_terminate(ch)
#define HTChunk_terminate(ch)   HTChunk_putc((ch), '\0')
/*

RETURN POINTER TO DATA

   This define converts a chunk to a normal char pointer so that it can be parsed to any
   ANSI C string function.
   
 */
#define HTChunkData(me)         ((me) ? (me)->data : NULL)
#define HTChunk_data(me)         ((me) ? (me)->data : NULL)
/*

CSTRING CONVERSIONS

   A Chunk may be build from an allocated string. The chunk assumes control of the passes
   string, elminating the need for additional allocations and string copies.
   Once a string is built, the chunk may be destroyed and the string kept around.
   
 */
extern HTChunk * HTChunk_fromCString    (char * str, int grow);
extern char * HTChunk_toCString         (HTChunk * ch);
/*

RETURN CURRENT SIZE

   Returns the current size of the chunk
   
 */
#define HTChunkSize(me)         ((me) ? (me)->size : -1)
#define HTChunk_size(me)         ((me) ? (me)->size : -1)
/*

 */
#endif
/*

   
   ___________________________________
   
                           @(#) $Id: HTChunk.html,v 2.33 1997/02/16 18:42:04 frystyk Exp $
                                                                                          
    */