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/* Copyright 2007, 2008 Peter Klausler. See COPYING for license. */
#include "all.h"
/*
* A locus is a position in a text. Insertions and
* deletions in the text prior to a locus cause
* automatic adjustments to the byte offset of a locus.
*/
#define DELETED (UNSET-1)
locus_t locus_create(struct view *view, position_t offset)
{
locus_t locus;
for (locus = 0; locus < view->loci; locus++)
if (view->locus[locus] == DELETED)
break;
if (locus == view->loci) {
view->locus = reallocate(view->locus,
(locus+1) * sizeof *view->locus);
view->loci++;
}
locus_set(view, locus, offset);
return locus;
}
void locus_destroy(struct view *view, locus_t locus)
{
if (locus < view->loci)
view->locus[locus] = DELETED;
}
position_t locus_get(struct view *view, locus_t locus)
{
position_t offset;
if (!view || locus >= view->loci)
return UNSET;
offset = view->locus[locus];
if (offset == UNSET)
return UNSET;
if ((int) offset < 0)
offset = 0;
else if (offset > view->bytes)
offset = view->bytes;
return offset;
}
position_t locus_set(struct view *view, locus_t locus, position_t offset)
{
if (offset != UNSET && offset > view->bytes)
offset = view->bytes;
if (locus < view->loci)
view->locus[locus] = offset;
return offset;
}
void loci_adjust(struct view *view, position_t offset, int delta)
{
int j;
if (delta < 0) {
position_t limit = offset - delta;
for (j = 0; j < view->loci; j++) {
position_t locus = view->locus[j];
if (locus == DELETED || locus == UNSET)
continue;
if (limit <= locus)
locus += delta;
else if (offset < locus)
locus = j == CURSOR ? offset : UNSET;
view->locus[j] = locus;
}
} else
for (j = 0; j < view->loci; j++) {
position_t locus = view->locus[j];
if (locus == DELETED || locus == UNSET)
continue;
if (offset <= locus)
view->locus[j] = locus + delta;
}
}
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