166 lines
2.7 KiB
C
166 lines
2.7 KiB
C
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/* $Header: /nw/tony/src/stevie/src/RCS/ptrfunc.c,v 1.5 89/03/11 22:43:12 tony Exp $
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*
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* The routines in this file attempt to imitate many of the operations
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* that used to be performed on simple character pointers and are now
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* performed on LNPTR's. This makes it easier to modify other sections
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* of the code. Think of an LNPTR as representing a position in the file.
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* Positions can be incremented, decremented, compared, etc. through
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* the functions implemented here.
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*/
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#include "stevie.h"
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/*
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* inc(p)
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*
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* Increment the line pointer 'p' crossing line boundaries as necessary.
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* Return 1 when crossing a line, -1 when at end of file, 0 otherwise.
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*/
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int
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inc(lp)
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register LNPTR *lp;
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{
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register char *p;
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if (lp && lp->linep)
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p = &(lp->linep->s[lp->index]);
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else
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return -1;
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if (*p != NUL) { /* still within line */
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lp->index++;
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return ((p[1] != NUL) ? 0 : 1);
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}
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if (lp->linep->next != Fileend->linep) { /* there is a next line */
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lp->index = 0;
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lp->linep = lp->linep->next;
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return 1;
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}
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return -1;
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}
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/*
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* dec(p)
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*
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* Decrement the line pointer 'p' crossing line boundaries as necessary.
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* Return 1 when crossing a line, -1 when at start of file, 0 otherwise.
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*/
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int
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dec(lp)
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register LNPTR *lp;
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{
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if (lp->index > 0) { /* still within line */
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lp->index--;
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return 0;
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}
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if (lp->linep &&
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lp->linep->prev != Filetop->linep) { /* there is a prior line */
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lp->linep = lp->linep->prev;
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lp->index = strlen(lp->linep->s);
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return 1;
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}
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lp->index = 0; /* stick at first char */
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return -1; /* at start of file */
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}
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/*
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* gchar(lp) - get the character at position "lp"
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*/
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int
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gchar(lp)
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register LNPTR *lp;
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{
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if (lp && lp->linep)
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return (lp->linep->s[lp->index]);
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else
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return 0;
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}
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/*
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* pchar(lp, c) - put character 'c' at position 'lp'
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*/
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void
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pchar(lp, c)
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register LNPTR *lp;
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char c;
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{
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lp->linep->s[lp->index] = c;
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}
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/*
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* pswap(a, b) - swap two position pointers
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*/
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void
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pswap(a, b)
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register LNPTR *a, *b;
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{
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LNPTR tmp;
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tmp = *a;
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*a = *b;
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*b = tmp;
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}
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/*
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* Position comparisons
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*/
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bool_t
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lt(a, b)
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register LNPTR *a, *b;
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{
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register int an, bn;
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an = LINEOF(a);
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bn = LINEOF(b);
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if (an != bn)
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return (an < bn);
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else
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return (a->index < b->index);
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}
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#if 0
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bool_t
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gt(a, b)
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LNPTR *a, *b;
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{
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register int an, bn;
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an = LINEOF(a);
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bn = LINEOF(b);
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if (an != bn)
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return (an > bn);
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else
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return (a->index > b->index);
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}
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#endif
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bool_t
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equal(a, b)
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register LNPTR *a, *b;
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{
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return (a->linep == b->linep && a->index == b->index);
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}
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bool_t
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ltoreq(a, b)
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register LNPTR *a, *b;
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{
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return (lt(a, b) || equal(a, b));
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}
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#if 0
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bool_t
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gtoreq(a, b)
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LNPTR *a, *b;
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{
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return (gt(a, b) || equal(a, b));
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}
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#endif
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