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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.geo;
/**
* Utility for parsing one geographical coordinate
*
* @author arnej27959
*/
class OneDegreeParser {
/** The parsed latitude (degrees north if positive). */
public double latitude = 0;
public boolean foundLatitude = false;
/** The parsed longitude (degrees east if positive). */
public double longitude = 0;
public boolean foundLongitude = false;
public static boolean isDigit(char ch) {
return (ch >= '0' && ch <= '9');
}
public static boolean isCompassDirection(char ch) {
return (ch == 'N' || ch == 'S' || ch == 'E' || ch == 'W');
}
private String parseString = null;
private int len = 0;
private int pos = 0;
public String toString() {
if (foundLatitude) {
return parseString + " -> latitude(" + latitude + ")";
} else {
return parseString + " -> longitude(" + longitude + ")";
}
}
private char getNextChar() throws IllegalArgumentException {
if (pos == len) {
pos++;
return 0;
} else if (pos > len) {
throw new IllegalArgumentException("position after end of string when parsing <"+parseString+">");
} else {
return parseString.charAt(pos++);
}
}
/**
* Parse the given string.
*
* The string must contain either a latitude or a longitude.
* A latitude should contain "N" or "S" and a number signifying
* degrees north or south, or a signed number.
* A longitude should contain "E" or "W" and a number
* signifying degrees east or west, or a signed number.
* <br>
* Fractional degrees are recommended as the main input format,
* but degrees plus fractional minutes may be used for testing.
* You can use the degree sign (U+00B0 as seen in unicode at
* http://www.unicode.org/charts/PDF/U0080.pdf) to separate
* degrees from minutes, put the direction (NSEW) between as a
* separator, or use a small letter 'o' as a replacement for the
* degrees sign.
* <br>
* Some valid input formats: <br>
* "37.416383" and "-122.024683" → Sunnyvale <br>
* "N37.416383" and "W122.024683" → Sunnyvale <br>
* "37N24.983" and "122W01.481" → same <br>
* "N37\u00B024.983" and "W122\u00B001.481" → same <br>
* "63.418417" and "10.433033" → Trondheim <br>
* "N63.418417" and "E10.433033" → same <br>
* "N63o25.105" and "E10o25.982" → same <br>
* "E10o25.982" and "N63o25.105" → same <br>
* "N63.418417" and "E10.433033" → same <br>
* "63N25.105" and "10E25.982" → same <br>
*
* @param assumeNorthSouth Latitude assumed, otherwise longitude
* @param toParse Latitude or longitude string to parse
*/
public OneDegreeParser(boolean assumeNorthSouth, String toParse) throws IllegalArgumentException {
this.parseString = toParse;
this.len = parseString.length();
consumeString(assumeNorthSouth);
}
private void consumeString(boolean assumeNorthSouth) throws IllegalArgumentException {
char ch = getNextChar();
double degrees = 0.0;
double minutes = 0.0;
double seconds = 0.0;
boolean degSet = false;
boolean minSet = false;
boolean secSet = false;
boolean dirSet = false;
boolean foundDot = false;
boolean foundDigits = false;
boolean findingLatitude = false;
boolean findingLongitude = false;
double sign = +1.0;
int lastpos = -1;
// sign must be first character in string if present:
if (ch == '+') {
// unary plus is a nop
ch = getNextChar();
} else if (ch == '-') {
sign = -1.0;
ch = getNextChar();
}
do {
// did we find a valid char?
boolean valid = false;
if (pos == lastpos) {
throw new IllegalArgumentException("internal logic error at <"+parseString+"> pos:"+pos);
} else {
lastpos = pos;
}
// first, see if we can find some number
double accum = 0.0;
if (isDigit(ch) || ch == '.') {
valid = true;
double divider = 1.0;
foundDot = false;
while (isDigit(ch)) {
foundDigits = true;
accum *= 10;
accum += (ch - '0');
ch = getNextChar();
}
if (ch == '.') {
foundDot = true;
ch = getNextChar();
while (isDigit(ch)) {
foundDigits = true;
accum *= 10;
accum += (ch - '0');
divider *= 10;
ch = getNextChar();
}
}
if (!foundDigits) {
throw new IllegalArgumentException("just a . is not a valid number when parsing <"+parseString+">");
}
accum /= divider;
}
// next, did we find a separator after the number?
// degree sign is a separator after degrees, before minutes
if (ch == '\u00B0' || ch == 'o') {
valid = true;
if (degSet) {
throw new IllegalArgumentException("degrees sign only valid just after degrees when parsing <"+parseString+">");
}
if (!foundDigits) {
throw new IllegalArgumentException("must have number before degrees sign when parsing <"+parseString+">");
}
if (foundDot) {
throw new IllegalArgumentException("cannot have fractional degrees before degrees sign when parsing <"+parseString+">");
}
ch = getNextChar();
}
// apostrophe is a separator after minutes, before seconds
if (ch == '\'') {
if (minSet || !degSet || !foundDigits) {
throw new IllegalArgumentException("minutes sign only valid just after minutes when parsing <"+parseString+">");
}
if (foundDot) {
throw new IllegalArgumentException("cannot have fractional minutes before minutes sign when parsing <"+parseString+">");
}
ch = getNextChar();
}
// if we found some number, assign it into the next unset variable
if (foundDigits) {
valid = true;
if (degSet) {
if (minSet) {
if (secSet) {
throw new IllegalArgumentException("extra number after full field when parsing <"+parseString+">");
} else {
seconds = accum;
secSet = true;
}
} else {
minutes = accum;
minSet = true;
if (foundDot) {
secSet = true;
}
}
} else {
degrees = accum;
degSet = true;
if (foundDot) {
minSet = true;
secSet = true;
}
}
foundDot = false;
foundDigits = false;
}
// there may to be a direction (NSEW) somewhere, too
if (isCompassDirection(ch)) {
valid = true;
if (dirSet) {
throw new IllegalArgumentException("already set direction once, cannot add direction: "+ch+" when parsing <"+parseString+">");
}
dirSet = true;
if (ch == 'S' || ch == 'W') {
sign = -1;
} else {
sign = 1;
}
if (ch == 'E' || ch == 'W') {
findingLongitude = true;
} else {
findingLatitude = true;
}
ch = getNextChar();
}
// lastly, did we find the end-of-string?
if (ch == 0) {
valid = true;
if (!dirSet) {
if (assumeNorthSouth) {
findingLatitude = true;
} else {
findingLongitude = true;
}
}
if (!degSet) {
throw new IllegalArgumentException("end of field without any number seen when parsing <"+parseString+">");
}
degrees += minutes / 60.0;
degrees += seconds / 3600.0;
degrees *= sign;
if (findingLatitude) {
if (degrees < -90.0 || degrees > 90.0) {
throw new IllegalArgumentException("out of range [-90,+90]: "+degrees+" when parsing <"+parseString+">");
}
latitude = degrees;
foundLatitude = true;
} else if (findingLongitude) {
if (degrees < -180.0 || degrees > 180.0) {
throw new IllegalArgumentException("out of range [-180,+180]: "+degrees+" when parsing <"+parseString+">");
}
longitude = degrees;
foundLongitude = true;
}
break;
}
if (!valid) {
throw new IllegalArgumentException("invalid character: "+ch+" when parsing <"+parseString+">");
}
} while (ch != 0);
// everything parsed OK
if (foundLatitude && foundLongitude) {
throw new IllegalArgumentException("found both latitude and longitude from: "+parseString);
}
if (foundLatitude || foundLongitude) {
return;
}
throw new IllegalArgumentException("found neither latitude nor longitude from: "+parseString);
}
}
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