Category : Files from Magazines
Archive   : PJ91.ZIP
Filename : TEXTBUF.H

/* textbuf.h -- Listing 1. */

#ifndef __TEXTBUF_H /* Make sure that textbuf.h isn't included */
#define __TEXTBUF_H /* twice, the endif is on the last line. */

#ifdef NEAR_HEAP
# define BMALLOC malloc /* Allocate memory for buffer. */
# define BFREE free /* Free memory used for buffer. */
# define MAXBSIZE 4096 /* Maximum row * col size. */
typedef char *bufptr; /* pointer to the buffer */
typedef int bufsize; /* holds max buffer size */

# define bufset( dst,c, size) memset (dst, c, size)
# define bufmove(dst,src,size) memmove(dst, src, size)
#else
# include /* needed for farmalloc prototype */
# define BMALLOC farmalloc
# define BFREE farfree
# define MAXBSIZE (0xffffU - 1) /* 64K - 1 */
typedef char far* bufptr;
typedef unsigned bufsize;

extern void _bufset ( bufptr p, const int c, bufsize size );
extern void _bufmove ( bufptr dst, bufptr src, bufsize size );
# define bufset(p,c,s) _bufset(p,c,s) /* in textbuf.c */
# define bufmove(d,s,size) _bufmove(d,s,size)
#endif

#define PUBLIC /* for documentation: globally accessible object. */

typedef struct
{
unsigned magic; /* Magic number for verification */
int nrows; /* Number of rows */
int ncols; /* Number of columns */
int row; /* Current cursor position, row */
int col; /* Current cursor position, column */
bufptr p; /* Character at that position */
bufptr buf; /* Actual buffer. */
}
textbuf;

/* B_LAST_LINE is passed a textbuf pointer and returns a pointer to
* the beginning of the last line of the buffer. The first line is
* pointed to by "buf."
*
* textbuf.magic is set to B_MAGIC when a textbuf is allocated. Use
* it to verify that a textbuf pointer is reasonable.
*/
#define B_LAST_LINE(b) ((b)->buf + (((b)->nrows - 1) * (b)->ncols))
#define B_MAGIC 0xabcdU
/*----------------------------------------------------------------------*/
PUBLIC textbuf *b_new( int nrows, int ncols );
PUBLIC void b_delete( textbuf *b );

PUBLIC textbuf *b_construct( textbuf *b, int nrows, int ncols );
PUBLIC int b_destruct( textbuf *b );
/*----------------------------------------------------------------------*/
#define b_current( b ) ( (b)->p )
#define b_advance( b ) ( (b)->col++, \
(b)->p++ \
)
#define b_row(b) ( (b)->row )
#define b_col(b) ( (b)->col )
#define b_nrows(b) ( (b)->nrows )
#define b_ncols(b) ( (b)->ncols )
#define b_setrc(b,r,c) ( ((b)->row = (r)), \
((b)->col = (c)), \
((b)->p = (b)->buf + ((r)*(b)->ncols)+(c)) \
)
#define b_ateol(b) ( (b)->col == ((b)->ncols - 1) )
#define b_ateob(b) ( (b)->row == ((b)->nrows - 1) )
#define b_valid(b,r,c) ( (b) \
&& ((b)->magic == B_MAGIC) \
&& (0 <= (r) && (r) < (b)->nrows) \
&& (0 <= (c) && (c) < (b)->ncols) \
)
#define b_clearbuf(b,c) ( b_setrc(b,0,0), \
bufset((b)->buf, (c), (b)->nrows * (b)->ncols)\
)
#define b_cr(b) ( ((b)->p -= (b)->col ), \
((b)->col = 0 ) \
)
#define b_lf(b) ( ( ++(b)->row ), \
( (b)->p += (b)->ncols ) \
)
#define b_clearline(b,c) ( b_cr(b), \
bufset( (b)->p, (c), (b)->ncols ) \
)
#define b_available(b) ( (b)->ncols - (b)->col )
#define b_insert_c(b,n,c) ( bufmove( (b)->p + n, (b)->p, \
b_available(b) - (n) ), \
bufset ( (b)->p , (c) , (n) ) \
)
#define b_delete_c(b,n,c) ( bufmove( (b)->p, (b)->p+(n), (n) ), \
bufset ( ( (b)->p - (b)->col) + \
( (b)->ncols - (n) ), (c), (n)) \
)
#define b_closeup(b,c) ( b_cr(b), \
bufmove( (b)->buf + (b)->ncols, (b)->buf, \
(b)->row * (b)->ncols ),\
bufset( (b)->buf, (c), (b)->ncols ) \
)
#define b_closedown(b,c) ( b_cr(b), \
bufmove( (b)->p, (b)->p + (b)->ncols, \
((b)->nrows-(b)->row-1) * (b)->ncols),\
bufset( B_LAST_LINE(b), (c), (b)->ncols ) \
)
#define b_openup(b, c) ( b_cr(b), \
bufmove( (b)->buf, (b)->buf + (b)->ncols, \
(b)->row * (b)->ncols ),\
bufset( (b)->p, (c), (b)->ncols ) \
)
#define b_opendown(b,c) ( b_cr(b), \
bufmove( (b)->p + (b)->ncols, (b)->p, \
((b)->nrows-(b)->row-1)*(b)->ncols),\
bufset( (b)->p, (c), (b)->ncols ) \
)
#endif /* #ifndef __TEXTBUF_H */