99 lines
1.7 KiB
C
99 lines
1.7 KiB
C
/*
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* p2d_gnuplot.c - File I/O in gnuplot format
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*
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* Written 2012, 2015 by Werner Almesberger
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* Copyright 2012, 2015 Werner Almesberger
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*/
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#include <stdbool.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <math.h>
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#include <errno.h>
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#include "poly2d.h"
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#define EPSILON 1e-6
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static void check_closed(struct p2d *p)
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{
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if (!p)
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return;
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if (hypot(p->v->x-p->last->x, p->v->y-p->last->y) > EPSILON)
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return;
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free(p->last);
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p->last = p->v;
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}
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struct p2d *p2d_read_gnuplot(FILE *file)
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{
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struct p2d *res = NULL, **last = &res, *p = NULL;
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char buf[1024];
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double x, y;
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int n;
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while (fgets(buf, sizeof(buf), file)) {
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if (*buf == '#')
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continue;
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n = sscanf(buf, "%lf %lf\n", &x, &y);
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switch (n) {
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case -1:
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check_closed(p);
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p = NULL;
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break;
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case 2:
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break;
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default:
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errno = EINVAL;
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return NULL;
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}
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if (!p) {
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p = p2d_new();
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*last = p;
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last = &p->next;
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}
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p2d_append(p, v2d_new(x, y));
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}
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check_closed(p);
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return res;
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}
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bool p2d_write_gnuplot(FILE *file, const struct p2d *p)
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{
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const struct v2d *v;
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v = p->v;
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while (v) {
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if (fprintf(file, "%g %g\n", v->x, v->y) < 0)
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return 0;
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v = v->next;
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if (v == p->v) {
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if (fprintf(file, "%g %g\n", v->x, v->y) < 0)
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return 0;
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break;
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}
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}
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return fprintf(file, "\n") >= 0;
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}
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bool p2d_write_gnuplot_all(FILE *file, const struct p2d *p)
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{
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while (p) {
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if (!p2d_write_gnuplot(file, p))
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return 0;
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p = p->next;
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}
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return 1;
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}
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