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-rw-r--r--micropeak/MicroData.java370
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diff --git a/micropeak/MicroData.java b/micropeak/MicroData.java
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+++ b/micropeak/MicroData.java
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+/*
+ * Copyright © 2012 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+package org.altusmetrum.micropeak;
+
+import java.lang.*;
+import java.io.*;
+import java.util.*;
+import org.altusmetrum.AltosLib.*;
+
+abstract class MicroIterator implements Iterator<Double> {
+ int i;
+ MicroData data;
+
+ public boolean hasNext() {
+ return i < data.pressures.length;
+ }
+
+ public MicroIterator (MicroData data) {
+ this.data = data;
+ i = 0;
+ }
+
+ public void remove() {
+ }
+}
+
+class MicroHeightIterator extends MicroIterator {
+ public Double next() {
+ return data.height(i++);
+ }
+
+ public MicroHeightIterator(MicroData data) {
+ super(data);
+ }
+}
+
+class MicroHeightIterable implements Iterable<Double> {
+ MicroData data;
+
+ public Iterator<Double> iterator() {
+ return new MicroHeightIterator(data);
+ }
+
+ public MicroHeightIterable(MicroData data) {
+ this.data = data;
+ }
+}
+
+class MicroSpeedIterator extends MicroIterator {
+ public Double next() {
+ return data.speed(i++);
+ }
+ public MicroSpeedIterator(MicroData data) {
+ super(data);
+ }
+}
+
+class MicroSpeedIterable implements Iterable<Double> {
+ MicroData data;
+
+ public Iterator<Double> iterator() {
+ return new MicroSpeedIterator(data);
+ }
+
+ public MicroSpeedIterable(MicroData data) {
+ this.data = data;
+ }
+}
+
+class MicroAccelIterator extends MicroIterator {
+ public Double next() {
+ return data.acceleration(i++);
+ }
+ public MicroAccelIterator(MicroData data) {
+ super(data);
+ }
+}
+
+class MicroAccelIterable implements Iterable<Double> {
+ MicroData data;
+
+ public Iterator<Double> iterator() {
+ return new MicroAccelIterator(data);
+ }
+
+ public MicroAccelIterable(MicroData data) {
+ this.data = data;
+ }
+}
+
+public class MicroData {
+ public int ground_pressure;
+ public int min_pressure;
+ public int[] pressures;
+ private double time_step;
+ private double ground_altitude;
+ private ArrayList<Integer> bytes;
+
+
+ class FileEndedException extends Exception {
+ }
+
+ class NonHexcharException extends Exception {
+ }
+
+ class InvalidCrcException extends Exception {
+ }
+
+ private int getc(InputStream f) throws IOException, FileEndedException {
+ int c = f.read();
+
+ if (c == -1)
+ throw new FileEndedException();
+ bytes.add(c);
+ return c;
+ }
+
+ private int get_nonwhite(InputStream f) throws IOException, FileEndedException {
+ int c;
+
+ for (;;) {
+ c = getc(f);
+ if (!Character.isWhitespace(c))
+ return c;
+ }
+ }
+
+ private int get_hexc(InputStream f) throws IOException, FileEndedException, NonHexcharException {
+ int c = get_nonwhite(f);
+
+ if ('0' <= c && c <= '9')
+ return c - '0';
+ if ('a' <= c && c <= 'f')
+ return c - 'a' + 10;
+ if ('A' <= c && c <= 'F')
+ return c - 'A' + 10;
+ throw new NonHexcharException();
+ }
+
+ private static final int POLY = 0x8408;
+
+ private int log_crc(int crc, int b) {
+ int i;
+
+ for (i = 0; i < 8; i++) {
+ if (((crc & 0x0001) ^ (b & 0x0001)) != 0)
+ crc = (crc >> 1) ^ POLY;
+ else
+ crc = crc >> 1;
+ b >>= 1;
+ }
+ return crc & 0xffff;
+ }
+
+ int file_crc;
+
+ private int get_hex(InputStream f) throws IOException, FileEndedException, NonHexcharException {
+ int a = get_hexc(f);
+ int b = get_hexc(f);
+
+ int h = (a << 4) + b;
+
+ file_crc = log_crc(file_crc, h);
+ return h;
+ }
+
+ private boolean find_header(InputStream f) throws IOException {
+ try {
+ for (;;) {
+ if (get_nonwhite(f) == 'M' && get_nonwhite(f) == 'P')
+ return true;
+ }
+ } catch (FileEndedException fe) {
+ return false;
+ }
+ }
+
+ private int get_32(InputStream f) throws IOException, FileEndedException, NonHexcharException {
+ int v = 0;
+ for (int i = 0; i < 4; i++) {
+ v += get_hex(f) << (i * 8);
+ }
+ return v;
+ }
+
+ private int get_16(InputStream f) throws IOException, FileEndedException, NonHexcharException {
+ int v = 0;
+ for (int i = 0; i < 2; i++) {
+ v += get_hex(f) << (i * 8);
+ }
+ return v;
+ }
+
+ private int swap16(int i) {
+ return ((i << 8) & 0xff00) | ((i >> 8) & 0xff);
+ }
+
+ public boolean crc_valid;
+
+ int mix_in (int high, int low) {
+ return high - (high & 0xffff) + low;
+ }
+
+ boolean closer (int target, int a, int b) {
+ return Math.abs (target - a) < Math.abs(target - b);
+ }
+
+ public double altitude(int i) {
+ return AltosConvert.pressure_to_altitude(pressures[i]);
+ }
+
+ public Iterable<Double> heights() {
+ return new MicroHeightIterable(this);
+ }
+
+ public Iterable<Double> speeds() {
+ return new MicroSpeedIterable(this);
+ }
+
+ public Iterable<Double> accels() {
+ return new MicroAccelIterable(this);
+ }
+
+ int fact(int n) {
+ if (n == 0)
+ return 1;
+ return n * fact(n-1);
+ }
+
+ int choose(int n, int k) {
+ return fact(n) / (fact(k) * fact(n-k));
+ }
+
+
+ public double avg_altitude(int center, int dist) {
+ int start = center - dist;
+ int stop = center + dist;
+
+ if (start < 0)
+ start = 0;
+ if (stop >= pressures.length)
+ stop = pressures.length - 1;
+
+ double sum = 0;
+ double div = 0;
+
+ int n = dist * 2;
+
+ for (int i = start; i <= stop; i++) {
+ int k = i - (center - dist);
+ int c = choose (n, k);
+
+ sum += c * pressures[i];
+ div += c;
+ }
+
+ double pres = sum / div;
+
+ double alt = AltosConvert.pressure_to_altitude(pres);
+ return alt;
+ }
+
+ public double height(int i) {
+ return altitude(i) - ground_altitude;
+ }
+
+ static final int speed_avg = 3;
+ static final int accel_avg = 5;
+
+ private double avg_speed(int center, int dist) {
+ if (center == 0)
+ return 0;
+
+ double ai = avg_altitude(center, dist);
+ double aj = avg_altitude(center - 1, dist);
+ double s = (ai - aj) / time_step;
+
+ return s;
+ }
+
+ public double speed(int i) {
+ return avg_speed(i, speed_avg);
+ }
+
+ public double acceleration(int i) {
+ if (i == 0)
+ return 0;
+ return (avg_speed(i, accel_avg) - avg_speed(i-1, accel_avg)) / time_step;
+ }
+
+ public double time(int i) {
+ return i * time_step;
+ }
+
+ public void save (OutputStream f) throws IOException {
+ for (int c : bytes)
+ f.write(c);
+ }
+
+ public MicroData (InputStream f) throws IOException {
+ bytes = new ArrayList<Integer>();
+ if (!find_header(f))
+ throw new IOException();
+ try {
+ file_crc = 0xffff;
+ ground_pressure = get_32(f);
+ min_pressure = get_32(f);
+ int nsamples = get_16(f);
+ pressures = new int[nsamples + 1];
+
+ ground_altitude = AltosConvert.pressure_to_altitude(ground_pressure);
+ int cur = ground_pressure;
+ pressures[0] = cur;
+ for (int i = 0; i < nsamples; i++) {
+ int k = get_16(f);
+ int same = mix_in(cur, k);
+ int up = mix_in(cur + 0x10000, k);
+ int down = mix_in(cur - 0x10000, k);
+
+ if (closer (cur, same, up)) {
+ if (closer (cur, same, down))
+ cur = same;
+ else
+ cur = down;
+ } else {
+ if (closer (cur, up, down))
+ cur = up;
+ else
+ cur = down;
+ }
+
+ pressures[i+1] = cur;
+ }
+
+ int current_crc = swap16(~file_crc & 0xffff);
+ int crc = get_16(f);
+
+ crc_valid = crc == current_crc;
+
+ time_step = 0.192;
+ } catch (FileEndedException fe) {
+ throw new IOException();
+ } catch (NonHexcharException ne) {
+ throw new IOException();
+ }
+ }
+
+ public MicroData() {
+ ground_pressure = 101000;
+ min_pressure = 101000;
+ pressures = new int[1];
+ pressures[0] = 101000;
+ }
+
+}
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