// These structures define a virtual buffer.  This is useful when
// a buffer is needed whose size may exceed 64K.  The virtual buffer
// consists of a number of logically contiguous blocks.

#ifndef VBUF_INCLUDED
#define VBUF_INCLUDED

// virtual buffer block
typedef struct VBlock {
    unsigned int Size;          // number of usable bytes in the block
    unsigned char *Address;     // address of block
    struct VBlock *Next;        // next block
} VBlock;


// virtual buffer
typedef struct {
    unsigned int BlockSize;     // allocated block size
    unsigned int NumBlocks;     // number of blocks
    VBlock *CurBlock;           // current block
    unsigned char *NextByte;    // next free byte in current block
    unsigned int FreeBytes;     // free bytes in current block
    VBlock *Block;              // list of blocks
} VBuf;



extern void VBufInit(VBuf *, unsigned int);
extern unsigned char *VBufCpy (VBuf *, unsigned char *, unsigned int);
extern unsigned char *VBufRead (VBuf *, unsigned int, unsigned short);
extern unsigned char *VBufSet (VBuf *, unsigned char, unsigned int);
extern VBlock *VBufFirstBlock (VBuf *);
extern VBlock *VBufNextBlock (VBlock *);

#endif /* VBUF_INCLUDED */