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The C Users' Group Library 1994 August
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wc-cdrom-cusersgrouplibrary-1994-08.iso
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vol_300
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313_01
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linefunc.c
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1990-04-22
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/* $Header: /nw2/tony/src/stevie/src/RCS/linefunc.c,v 1.2 89/03/11 22:42:32 tony Exp $
*
* Basic line-oriented motions.
*/
#include "stevie.h"
/*
* nextline(curr)
*
* Return a pointer to the beginning of the next line after the one
* referenced by 'curr'. Return NULL if there is no next line (at EOF).
*/
LPTR *
nextline(curr)
LPTR *curr;
{
static LPTR next;
if (curr->linep->next != Fileend->linep) {
next.index = 0;
next.linep = curr->linep->next;
return &next;
}
return (LPTR *) NULL;
}
/*
* prevline(curr)
*
* Return a pointer to the beginning of the line before the one
* referenced by 'curr'. Return NULL if there is no prior line.
*/
LPTR *
prevline(curr)
LPTR *curr;
{
static LPTR prev;
if (curr->linep->prev != Filetop->linep) {
prev.index = 0;
prev.linep = curr->linep->prev;
return &prev;
}
return (LPTR *) NULL;
}
/*
* coladvance(p,col)
*
* Try to advance to the specified column, starting at p.
*/
LPTR *
coladvance(p, col)
LPTR *p;
register int col;
{
static LPTR lp;
register int c, in;
lp.linep = p->linep;
lp.index = p->index;
/* If we're on a blank ('\n' only) line, we can't do anything */
if (lp.linep->s[lp.index] == '\0')
return &lp;
/* try to advance to the specified column */
for ( c=0; col-- > 0; c++ ) {
/* Count a tab for what it's worth (if list mode not on) */
if ( gchar(&lp) == TAB && !P(P_LS) ) {
in = ((P(P_TS)-1) - c%P(P_TS));
col -= in;
c += in;
}
/* Don't go past the end of */
/* the file or the line. */
if (inc(&lp)) {
dec(&lp);
break;
}
}
return &lp;
}