blob: 5f97bd8fa16048b0820e7da238ebe4e4c1db28cd [file] [log] [blame]
library services.src.correction.strings;
import 'dart:math';
/**
* "$"
*/
const int CHAR_DOLLAR = 0x24;
/**
* "."
*/
const int CHAR_DOT = 0x2E;
/**
* "_"
*/
const int CHAR_UNDERSCORE = 0x5F;
String capitalize(String str) {
if (isEmpty(str)) {
return str;
}
return str.substring(0, 1).toUpperCase() + str.substring(1);
}
String decapitalize(String str) {
if (isEmpty(str)) {
return str;
}
return str.substring(0, 1).toLowerCase() + str.substring(1);
}
int compareStrings(String a, String b) {
if (a == b) {
return 0;
}
if (a == null) {
return 1;
}
if (b == null) {
return -1;
}
return a.compareTo(b);
}
/**
* Counts how many times [sub] appears in [str].
*/
int countMatches(String str, String sub) {
if (isEmpty(str) || isEmpty(sub)) {
return 0;
}
int count = 0;
int idx = 0;
while ((idx = str.indexOf(sub, idx)) != -1) {
count++;
idx += sub.length;
}
return count;
}
/**
* Returns the number of characters common to the end of [a] and the start
* of [b].
*/
int findCommonOverlap(String a, String b) {
int a_length = a.length;
int b_length = b.length;
// all empty
if (a_length == 0 || b_length == 0) {
return 0;
}
// truncate
if (a_length > b_length) {
a = a.substring(a_length - b_length);
} else if (a_length < b_length) {
b = b.substring(0, a_length);
}
int text_length = min(a_length, b_length);
// the worst case
if (a == b) {
return text_length;
}
// increase common length one by one
int length = 0;
while (length < text_length) {
if (a.codeUnitAt(text_length - 1 - length) != b.codeUnitAt(length)) {
break;
}
length++;
}
return length;
}
/**
* Return the number of characters common to the start of [a] and [b].
*/
int findCommonPrefix(String a, String b) {
int n = min(a.length, b.length);
for (int i = 0; i < n; i++) {
if (a.codeUnitAt(i) != b.codeUnitAt(i)) {
return i;
}
}
return n;
}
/**
* Return the number of characters common to the end of [a] and [b].
*/
int findCommonSuffix(String a, String b) {
int a_length = a.length;
int b_length = b.length;
int n = min(a_length, b_length);
for (int i = 1; i <= n; i++) {
if (a.codeUnitAt(a_length - i) != b.codeUnitAt(b_length - i)) {
return i - 1;
}
}
return n;
}
/**
* Returns a list of words for the given camel case string.
*
* 'getCamelWords' => ['get', 'Camel', 'Words']
* 'getHTMLText' => ['get', 'HTML', 'Text']
*/
List<String> getCamelWords(String str) {
if (str == null || str.isEmpty) {
return <String>[];
}
List<String> parts = <String>[];
bool wasLowerCase = false;
bool wasUpperCase = false;
int wordStart = 0;
for (int i = 0; i < str.length; i++) {
int c = str.codeUnitAt(i);
var newLowerCase = isLowerCase(c);
var newUpperCase = isUpperCase(c);
// myWord
// | ^
if (wasLowerCase && newUpperCase) {
parts.add(str.substring(wordStart, i));
wordStart = i;
}
// myHTMLText
// | ^
if (wasUpperCase &&
newUpperCase &&
i + 1 < str.length &&
isLowerCase(str.codeUnitAt(i + 1))) {
parts.add(str.substring(wordStart, i));
wordStart = i;
}
wasLowerCase = newLowerCase;
wasUpperCase = newUpperCase;
}
parts.add(str.substring(wordStart));
return parts;
}
/**
* Checks if [str] is `null`, empty or is whitespace.
*/
bool isBlank(String str) {
if (str == null) {
return true;
}
if (str.isEmpty) {
return true;
}
return str.codeUnits.every(isSpace);
}
bool isDigit(int c) {
return c >= 0x30 && c <= 0x39;
}
bool isEmpty(String str) {
return str == null || str.isEmpty;
}
bool isLetter(int c) {
return (c >= 0x41 && c <= 0x5A) || (c >= 0x61 && c <= 0x7A);
}
bool isLetterOrDigit(int c) {
return isLetter(c) || isDigit(c);
}
bool isLowerCase(int c) {
return c >= 0x61 && c <= 0x7A;
}
bool isSpace(int c) => c == 0x20 || c == 0x09;
bool isUpperCase(int c) {
return c >= 0x41 && c <= 0x5A;
}
bool isWhitespace(int c) {
return isSpace(c) || c == 0x0D || c == 0x0A;
}
String remove(String str, String remove) {
if (isEmpty(str) || isEmpty(remove)) {
return str;
}
return str.replaceAll(remove, '');
}
String removeEnd(String str, String remove) {
if (isEmpty(str) || isEmpty(remove)) {
return str;
}
if (str.endsWith(remove)) {
return str.substring(0, str.length - remove.length);
}
return str;
}
String removeStart(String str, String remove) {
if (isEmpty(str) || isEmpty(remove)) {
return str;
}
if (str.startsWith(remove)) {
return str.substring(remove.length);
}
return str;
}
String repeat(String s, int n) {
StringBuffer sb = new StringBuffer();
for (int i = 0; i < n; i++) {
sb.write(s);
}
return sb.toString();
}
/**
* Gets the substring after the last occurrence of a separator.
* The separator is not returned.
*/
String substringAfterLast(String str, String separator) {
if (isEmpty(str)) {
return str;
}
if (isEmpty(separator)) {
return '';
}
int pos = str.lastIndexOf(separator);
if (pos == -1) {
return str;
}
return str.substring(pos + separator.length);
}