buffer.c

/* buffer.c -- implements buffer.h */
#include "buffer.h"

/* Buffer management.  Some of the functions are internal, and some are
   actually attached to user keys.  Like everyone else, they set hints for
   the display system.

    modified by Petri Kutvonen
 */

#include <stdlib.h>
#include <string.h>

#include "defines.h"
#include "file.h"
#include "input.h"
#include "list.h"
#include "mlout.h"
#include "utf8.h"
#include "util.h"
#include "window.h"


buffer_p curbp ;        /* Current buffer               */
buffer_p bheadp ;       /* Head of list of buffers      */
buffer_p blistp ;       /* Buffer for C-X C-B           */

const char *modename[ NUMMODES] = { /* name of modes */
    "Wrap", "Cmode", "Exact", "View", "Over",
    "Magic",
    "Asave", "Utf-8", "Dos", "Mac"
} ;

int gmode = 0 ;         /* global editor mode           */

static int makelist( int iflag) ;
static int addline( char *text) ;
static void l_to_a( char *buf, int width, long num) ;


/* Attach a buffer to a window.  The values of dot and mark come from the
   buffer if the use count is 0.  Otherwise, they come from some other
   window.
 */
BINDABLE( usebuffer) {
    char *bufn ;

/* Get buffer name */
    int status = newmlarg( &bufn, "select-buffer: ", sizeof( bname_t)) ;
    if( status != TRUE)
        return status ;

/* Find buffer in list */
    buffer_p bp = bfind( bufn, TRUE, 0) ;
    free( bufn) ;
    if( bp == NULL)
        return FALSE ;

/* Switch to buffer */
    return swbuffer( bp) ;
}


/* switch to the next buffer in the buffer list
 *
 * int f, n;        default flag, numeric argument
 */
BINDABLE( nextbuffer) {
    buffer_p bp = NULL ;    /* eligible buffer to switch to */

    /* make sure the arg is legit */
    if( f == FALSE)
        n = 1 ;

    if( n < 1)
        return FALSE ;

    buffer_p bbp = curbp ;  /* eligible buffer to switch to */
    while( n-- > 0) {
        /* advance to the next buffer */
        bp = bbp->b_bufp ;

        /* cycle through the buffers to find an eligible one */
        while( bp == NULL || bp->b_flag & BFINVS) {
            if (bp == NULL)
                bp = bheadp ;
            else
                bp = bp->b_bufp ;

            /* don't get caught in an infinite loop! */
            if( bp == bbp)
                return FALSE ;
        }

        bbp = bp ;
    }

    return swbuffer( bp) ;
}


/* make buffer BP current
 */
int swbuffer( buffer_p bp) {
    window_p wp ;

    if (--curbp->b_nwnd == 0) { /* Last use.            */
        curbp->b_dotp = curwp->w_dotp;
        curbp->b_doto = curwp->w_doto;
        curbp->b_markp = curwp->w_markp;
        curbp->b_marko = curwp->w_marko;
    }
    curbp = bp;     /* Switch.              */
    if (curbp->b_active != TRUE) {  /* buffer not active yet */
        /* read it in and activate it */
        readin(curbp->b_fname, TRUE);
        curbp->b_dotp = lforw(curbp->b_linep);
        curbp->b_doto = 0;
        curbp->b_active = TRUE;
        curbp->b_mode |= gmode; /* P.K. */
    }
    curwp->w_bufp = bp;
    curwp->w_linep = bp->b_linep;   /* For macros, ignored. */
    curwp->w_flag |= WFMODE | WFFORCE | WFHARD; /* Quite nasty.         */
    if (bp->b_nwnd++ == 0) {    /* First use.           */
        curwp->w_dotp = bp->b_dotp;
        curwp->w_doto = bp->b_doto;
        curwp->w_markp = bp->b_markp;
        curwp->w_marko = bp->b_marko;
        cknewwindow();
        return TRUE;
    }
    wp = wheadp;        /* Look for old.        */
    while (wp != NULL) {
        if (wp != curwp && wp->w_bufp == bp) {
            curwp->w_dotp = wp->w_dotp;
            curwp->w_doto = wp->w_doto;
            curwp->w_markp = wp->w_markp;
            curwp->w_marko = wp->w_marko;
            break;
        }
        wp = wp->w_wndp;
    }
    cknewwindow();
    return TRUE;
}


/* Dispose of a buffer, by name.  Ask for the name.  Look it up (don't get
   too upset if it isn't there at all!).  Get quite upset if the buffer is
   being displayed.  Clear the buffer (ask if the buffer has been changed).
   Then free the header line and the buffer header.  Bound to "C-X K".
 */
BINDABLE( killbuffer) {
    buffer_p bp ;
    int status ;
    char *bufn ;

/* Get buffer name */
    status = newmlarg( &bufn, "delete-buffer: ", sizeof( bname_t)) ;
    if( status != TRUE)
        return status ;

/* Find buffer in list */
    bp = bfind( bufn, FALSE, 0) ;
    free( bufn) ;
    if( bp == NULL) /* Easy if unknown. */
        return TRUE ;

    if( bp->b_flag & BFINVS)    /* Deal with special buffers    */
        return TRUE ;           /* by doing nothing.            */

    return zotbuf( bp) ;
}


/* kill the buffer pointed to by bp
 */
int zotbuf( buffer_p bp) {
    if( bp->b_nwnd != 0)	/* Error if on screen.  */
        return mloutfail( "Buffer is being displayed") ;

    int s = bclear( bp) ;	/* Blow text away.      */
    if( s != TRUE)
        return s ;

    free( bp->b_linep) ;	/* Release header line. */

/* unlink buffer from buffer chain */
	if( bheadp == bp)
		bheadp = bp->b_bufp ;
	else for( buffer_p prev = bheadp ; prev != NULL ; prev = prev->b_bufp)
		if( prev->b_bufp == bp) {
			prev->b_bufp = bp->b_bufp ;
			break ;
		}

    free( bp) ;				/* Release buffer block */
    return TRUE ;
}


/* Rename the current buffer
 *
 * int f, n;        default Flag & Numeric arg
 */
BINDABLE( namebuffer) {
    char *bufn ;        /* buffer to hold buffer name */
    int status ;

/* iterate until it gets a unique new buffer name */
    do {
    /* prompt for it */
        status = newmlarg( &bufn, "name-buffer: ", sizeof( bname_t)) ;
        if( status != TRUE)
            return status ;

    /* and check for duplicates */
        for( buffer_p bp = bheadp ; bp != NULL ; bp = bp->b_bufp) {
            if( bp != curbp) {  /* it's ok to rename buffer to same, so skip */
            /* retry if the names are the same */
                if( strcmp( bufn, bp->b_bname) == 0) {
                    free( bufn) ;
                    status = FALSE ;    /* try again */
                    break ;
                }
            }
        }
    } while( !status) ;

/* copy buffer name to structure */
    mystrscpy( curbp->b_bname, bufn, sizeof( bname_t)) ;
    free( bufn) ;

    curwp->w_flag |= WFMODE ;   /* make mode line replot */
    mloutstr( "") ; /* erase message line */
    return TRUE ;
}


/* List all of the active buffers.  First update the special buffer that
   holds the list.  Next make sure at least 1 window is displaying the
   buffer list, splitting the screen if this is what it takes.  Lastly,
   repaint all of the windows that are displaying the list.  Bound to "C-X
   C-B".
   
   A numeric argument forces it to list invisible buffers as well.
 */
BINDABLE( listbuffers) {
    window_p wp ;

    int s = makelist( f) ;
    if( s != TRUE)
        return s ;

    if( blistp->b_nwnd == 0) {  /* Not on screen yet.   */
        buffer_p bp ;

        if( (wp = wpopup()) == NULL)
            return FALSE ;

        bp = wp->w_bufp ;
        if( --bp->b_nwnd == 0) {
            bp->b_dotp = wp->w_dotp ;
            bp->b_doto = wp->w_doto ;
            bp->b_markp = wp->w_markp ;
            bp->b_marko = wp->w_marko ;
        }
        
        wp->w_bufp = blistp ;
        ++blistp->b_nwnd ;
    }
    
    for( wp = wheadp ; wp != NULL ; wp = wp->w_wndp) {
        if( wp->w_bufp == blistp) {
            wp->w_linep = lforw( blistp->b_linep) ;
            wp->w_dotp = lforw( blistp->b_linep) ;
            wp->w_doto = 0 ;
            wp->w_markp = NULL ;
            wp->w_marko = 0 ;
            wp->w_flag |= WFMODE | WFHARD ;
        }
    }
    
    return TRUE ;
}


/* This routine rebuilds the text in the special secret buffer that holds
   the buffer list.  It is called by the list buffers command.  Return TRUE
   if everything works.  Return FALSE if there is an error (if there is no
   memory).  Iflag indicates wether to list hidden buffers.

   int iflag;       list hidden buffer flag
 */
/* Layout: "ACT MODES           Size Buffer          File"
            AAA MMMMMMMMMMSSSSSSSSSS BBBBBBBBBBBBBBB FFF...
   FNAMSTART ----------------------------------------^
*/
#define FNAMSTART (3 + 1 + NUMMODES + 10 + 1 + (sizeof( bname_t) - 1) + 1)

static void do_layout( char *line, int mode) {
    int i ;

    /* build line to report global mode settings */
    strcpy( line, "    WCEVOmAUDM           Global Modes") ;

    /* output the mode codes */
    for( i = 0 ; i < NUMMODES ; i++)
        if( 0 == (mode & (1 << i)))
            line[ 4 + i] = '.' ;
}


static unsigned int utf8_disp_len( const char *s) {
    unsigned int len = 0 ;

    while( *s) {
        unicode_t c ;

        s += utf8_to_unicode( s, 0, 4, &c) ;
        len += utf8_width( c) ;
    }

    return len ;
}


static int makelist( int iflag) {
    char line[ FNAMSTART + sizeof( fname_t)] ;

    blistp->b_flag &= ~BFCHG;   /* Don't complain! Mute bclear() */
    int s = bclear( blistp) ;   /* Blow old text away   */
    if( s != TRUE)
        return s ;

    blistp->b_fname[ 0] = 0 ;   /* in case of user override */

    if( addline("ACT MODES           Size Buffer          File") == FALSE
    ||  addline("‾‾‾ ‾‾‾‾‾           ‾‾‾‾ ‾‾‾‾‾‾          ‾‾‾‾") == FALSE)
        return FALSE ;

/* report global mode settings */
    do_layout( line, gmode) ;
    if( addline( line) == FALSE)
        return FALSE ;

/* output the list of buffers */
    for( buffer_p bp = bheadp ; bp != NULL ; bp = bp->b_bufp) {
        int c ;

    /* skip invisible buffers if iflag is false */
        if (((bp->b_flag & BFINVS) != 0) && (iflag != TRUE))
            continue;

        do_layout( line, bp->b_mode) ;
        char *cp1 = line ;    /* Start at left edge   */

    /* output status of ACTIVE flag ('@' when the file has been read in) */
        *cp1++ = (bp->b_active == TRUE) ? '@' : ' ' ;

    /* report if the file is truncated */
        *cp1++ = ((bp->b_flag & BFTRUNC) != 0) ? '#' : ' ' ;

    /* output status of changed flag ('*' when the buffer is changed) */
        *cp1 = ((bp->b_flag & BFCHG) != 0) ? '*' : ' ' ;

    /* Buffer size */
        long nbytes = 0L;    /* Count bytes in buf.  */
        long nlines = 0 ;
        for( line_p lp = lforw( bp->b_linep) ; lp != bp->b_linep ;
                                                            lp = lforw( lp)) {
            nbytes += (long) llength(lp) + 1L;
            nlines += 1 ;
        }

        if( bp->b_mode & MDDOS)
            nbytes += nlines ;

        l_to_a( &line[ 14], 10 + 1, nbytes) ;   /* "%10d" formatted numbers */
        cp1 = &line[ 24] ;
        *cp1++ = ' ' ;

    /* Display buffer name */
        char *cp2 = &bp->b_bname[ 0] ;
        while( (c = *cp2++) != 0)
            *cp1++ = c;

    /* Pad with spaces to max buffer name length */
        int len = sizeof bp->b_bname ;
        len -= utf8_disp_len( bp->b_bname) ;
        while( len--)
            *cp1++ = ' ' ;

    /* Display filename if any */
        if( bp->b_fname[ 0] != 0)
            mystrscpy( cp1, bp->b_fname, &line[ sizeof line] - cp1) ;
        else
            *cp1 = 0 ;                  /* Terminate string */

        if( addline( line) == FALSE)    /* Add to the buffer.   */
            return FALSE ;
    }

    return TRUE ;       /* All done             */
}


static void l_to_a(char *buf, int width, long num) {
    buf[ --width] = 0 ;     /* End of string.       */
    while (num >= 10) { /* Conditional digits.  */
        buf[--width] = (int) (num % 10L) + '0';
        num /= 10L;
    }
    buf[--width] = (int) num + '0'; /* Always 1 digit.      */
    while( width > 0)   /* Pad with blanks.     */
        buf[--width] = ' ';
}


/* The argument "text" points to a string.  Append this line to the buffer
   list buffer.  Handcraft the EOL on the end.  Return TRUE if it worked
   and FALSE if you ran out of room.
 */
static int addline( char *text) {
    int ntext = strlen( text) ;
    line_p lp = lalloc( ntext) ;
    if( lp == NULL)
        return FALSE ;

    for( int i = 0 ; i < ntext ; ++i)
        lputc( lp, i, text[ i]) ;

    blistp->b_linep->l_bp->l_fp = lp ;      /* Hook onto the end    */
    lp->l_bp = blistp->b_linep->l_bp ;
    blistp->b_linep->l_bp = lp ;
    lp->l_fp = blistp->b_linep ;
    if( blistp->b_dotp == blistp->b_linep)  /* If "." is at the end */
        blistp->b_dotp = lp ;               /* move it to new line  */

    return TRUE ;
}


/* Look through the list of buffers.  Return TRUE if there are any changed
   buffers.  Buffers that hold magic internal stuff are not considered; who
   cares if the list of buffer names is hacked.  Return FALSE if no buffers
   have been changed.
 */
boolean anycb( void) {
    for( buffer_p bp = bheadp ; bp != NULL ; bp = bp->b_bufp) {
        if( (bp->b_flag & (BFINVS | BFCHG)) == BFCHG)
            return TRUE ;
    }

    return FALSE ;
}


/* Find a buffer, by name.  Return a pointer to the buffer structure
   associated with it.  If the buffer is not found and the "create_f" is
   TRUE, create it.  The "flags" is the settings for the buffer flags.
 */
buffer_p bfind( const char *bname, boolean create_f, int flags) {
    buffer_p bp ;

    for( bp = bheadp ; bp != NULL ; bp = bp->b_bufp)
        if( strcmp( bname, bp->b_bname) == 0)
            return bp ;

    if( create_f != FALSE) {
    /* allocate empty buffer */
        bp = malloc( sizeof *bp) ;
        if( bp == NULL)
            return NULL ;

        line_p lp = lalloc( 0) ;
        if( lp == NULL) {
            free( bp) ;
            return NULL ;
        }

        lp->l_fp = lp ;
        lp->l_bp = lp ;
        bp->b_linep = lp ;
        bp->b_dotp = lp ;
        bp->b_doto = 0 ;

    /* find the place in the list to insert this buffer */
        if( bheadp == NULL || strcmp( bheadp->b_bname, bname) > 0) {
        /* insert at the beginning */
            bp->b_bufp = bheadp ;
            bheadp = bp ;
        } else {
            buffer_p sb ;   /* buffer to insert after */

            for( sb = bheadp ; sb->b_bufp != NULL ; sb = sb->b_bufp)
                if( strcmp( sb->b_bufp->b_bname, bname) > 0)
                    break ;

        /* and insert it */
            bp->b_bufp = sb->b_bufp ;
            sb->b_bufp = bp ;
        }

        /* and set up the other buffer fields */
        bp->b_active = TRUE ;
        bp->b_markp = NULL ;
        bp->b_marko = 0 ;
        bp->b_flag = flags ;
        bp->b_mode = gmode ;
        bp->b_nwnd = 0 ;
        bp->b_fname[ 0] = '\0' ;
        mystrscpy( bp->b_bname, bname, sizeof( bname_t)) ;
    }

    return bp ;
}


/* This routine blows away all of the text in a buffer.  If the buffer is
   marked as changed then we ask if it is ok to blow it away; this is to
   save the user the grief of losing text.  The window chain is nearly
   always wrong if this gets called; the caller must arrange for the
   updates that are required.  Return TRUE if everything looks good.
 */
int bclear( buffer_p bp) {
    int s ;

    if( (bp->b_flag & (BFINVS | BFCHG)) == BFCHG    /* regular and changed */
    &&  (s = mlyesno( "Discard changes")) != TRUE)
        return s ;

    bp->b_flag &= ~BFCHG ;      /* Not changed          */
	line_p lp = bp->b_linep ;
	if( lp->l_fp != lp) {	/* non empty buffer */
	/* turn line ring into a list and delete it */
		lp->l_bp->l_fp = NULL ;
		freelist( (list_p) lp->l_fp) ;
		lp->l_fp = lp->l_bp = lp ;

	/* Fix dots and marks */
	    bp->b_dotp = bp->b_linep ;  /* Fix "."              */
    	bp->b_doto = 0 ;
    	bp->b_markp = NULL ;        /* Invalidate "mark"    */
    	bp->b_marko = 0 ;
		if( bp->b_nwnd)	/* buffer is displayed */
			for( window_p wp = wheadp ; wp ; wp = wp->w_wndp)
				if( wp->w_bufp == bp) {
	            	wp->w_linep = wp->w_dotp = lp ;
    	        	wp->w_doto = 0 ;
        	    	wp->w_markp = NULL ;
            		wp->w_marko = 0 ;
				}
	}

    return TRUE ;
}


/* unmark the current buffers change flag
 *
 * int f, n;        unused command arguments
 */
BINDABLE( unmark) {
    curbp->b_flag &= ~BFCHG ;
    curwp->w_flag |= WFMODE ;
    return TRUE ;
}

/* end of buffer.c */