/**
* Returns str, left-padded with pad to a length of len. For example: ('hi', 5, '??') =>
* '???hi' ('hi', 1, '??') => 'h'
*/
public UTF8String lpad(int len, UTF8String pad) {
int spaces = len - this.numChars(); // number of char need to pad
if (spaces <= 0 || pad.numBytes() == 0) {
// no padding at all, return the substring of the current string
return substring(0, len);
} else {
int padChars = pad.numChars();
int count = spaces / padChars; // how many padding string needed
// the partial string of the padding
UTF8String remain = pad.substring(0, spaces - padChars * count);
byte[] data = new byte[this.numBytes + pad.numBytes * count + remain.numBytes];
int offset = 0;
int idx = 0;
while (idx < count) {
copyMemory(pad.base, pad.offset, data, BYTE_ARRAY_OFFSET + offset, pad.numBytes);
++idx;
offset += pad.numBytes;
}
copyMemory(remain.base, remain.offset, data, BYTE_ARRAY_OFFSET + offset, remain.numBytes);
offset += remain.numBytes;
copyMemory(this.base, this.offset, data, BYTE_ARRAY_OFFSET + offset, numBytes());
return UTF8String.fromBytes(data);
}
}
/**
* Returns the position of the first occurrence of substr in current string from the specified
* position (0-based index).
*
* @param v the string to be searched
* @param start the start position of the current string for searching
* @return the position of the first occurrence of substr, if not found, -1 returned.
*/
public int indexOf(UTF8String v, int start) {
if (v.numBytes() == 0) {
return 0;
}
// locate to the start position.
int i = 0; // position in byte
int c = 0; // position in character
while (i < numBytes && c < start) {
i += numBytesForFirstByte(getByte(i));
c += 1;
}
do {
if (i + v.numBytes > numBytes) {
return -1;
}
if (ByteArrayMethods.arrayEquals(base, offset + i, v.base, v.offset, v.numBytes)) {
return c;
}
i += numBytesForFirstByte(getByte(i));
c += 1;
} while (i < numBytes);
return -1;
}
public UTF8String[] split(UTF8String pattern, int limit) {
String[] splits = toString().split(pattern.toString(), limit);
UTF8String[] res = new UTF8String[splits.length];
for (int i = 0; i < res.length; i++) {
res[i] = fromString(splits[i]);
}
return res;
}
public UTF8String trimLeft() {
int s = 0;
// skip all of the space (0x20) in the left side
while (s < this.numBytes && getByte(s) <= 0x20 && getByte(s) >= 0x00) s++;
if (s == this.numBytes) {
// empty string
return UTF8String.fromBytes(new byte[0]);
} else {
return copyUTF8String(s, this.numBytes - 1);
}
}
public UTF8String trimRight() {
int e = numBytes - 1;
// skip all of the space (0x20) in the right side
while (e >= 0 && getByte(e) <= 0x20 && getByte(e) >= 0x00) e--;
if (e < 0) {
// empty string
return UTF8String.fromBytes(new byte[0]);
} else {
return copyUTF8String(0, e);
}
}
@Override
public int compareTo(@Nonnull final UTF8String other) {
int len = Math.min(numBytes, other.numBytes);
// TODO: compare 8 bytes as unsigned long
for (int i = 0; i < len; i++) {
// In UTF-8, the byte should be unsigned, so we should compare them as unsigned int.
int res = (getByte(i) & 0xFF) - (other.getByte(i) & 0xFF);
if (res != 0) {
return res;
}
}
return numBytes - other.numBytes;
}
/** Returns whether this contains `substring` or not. */
public boolean contains(final UTF8String substring) {
if (substring.numBytes == 0) {
return true;
}
byte first = substring.getByte(0);
for (int i = 0; i <= numBytes - substring.numBytes; i++) {
if (getByte(i) == first && matchAt(substring, i)) {
return true;
}
}
return false;
}
public UTF8String reverse() {
byte[] result = new byte[this.numBytes];
int i = 0; // position in byte
while (i < numBytes) {
int len = numBytesForFirstByte(getByte(i));
copyMemory(
this.base, this.offset + i, result, BYTE_ARRAY_OFFSET + result.length - i - len, len);
i += len;
}
return UTF8String.fromBytes(result);
}
public UTF8String trim() {
int s = 0;
int e = this.numBytes - 1;
// skip all of the space (0x20) in the left side
while (s < this.numBytes && getByte(s) <= 0x20 && getByte(s) >= 0x00) s++;
// skip all of the space (0x20) in the right side
while (e >= 0 && getByte(e) <= 0x20 && getByte(e) >= 0x00) e--;
if (s > e) {
// empty string
return UTF8String.fromBytes(new byte[0]);
} else {
return copyUTF8String(s, e);
}
}
public UTF8String repeat(int times) {
if (times <= 0) {
return EMPTY_UTF8;
}
byte[] newBytes = new byte[numBytes * times];
copyMemory(this.base, this.offset, newBytes, BYTE_ARRAY_OFFSET, numBytes);
int copied = 1;
while (copied < times) {
int toCopy = Math.min(copied, times - copied);
System.arraycopy(newBytes, 0, newBytes, copied * numBytes, numBytes * toCopy);
copied += toCopy;
}
return UTF8String.fromBytes(newBytes);
}
/**
* Encodes a string into a Soundex value. Soundex is an encoding used to relate similar names, but
* can also be used as a general purpose scheme to find word with similar phonemes.
* https://en.wikipedia.org/wiki/Soundex
*/
public UTF8String soundex() {
if (numBytes == 0) {
return EMPTY_UTF8;
}
byte b = getByte(0);
if ('a' <= b && b <= 'z') {
b -= 32;
} else if (b < 'A' || 'Z' < b) {
// first character must be a letter
return this;
}
byte[] sx = {'0', '0', '0', '0'};
sx[0] = b;
int sxi = 1;
int idx = b - 'A';
byte lastCode = US_ENGLISH_MAPPING[idx];
for (int i = 1; i < numBytes; i++) {
b = getByte(i);
if ('a' <= b && b <= 'z') {
b -= 32;
} else if (b < 'A' || 'Z' < b) {
// not a letter, skip it
lastCode = '0';
continue;
}
idx = b - 'A';
byte code = US_ENGLISH_MAPPING[idx];
if (code == '7') {
// ignore it
} else {
if (code != '0' && code != lastCode) {
sx[sxi++] = code;
if (sxi > 3) break;
}
lastCode = code;
}
}
return UTF8String.fromBytes(sx);
}
/*
* Returns the index of the string `match` in this String. This string has to be a comma separated
* list. If `match` contains a comma 0 will be returned. If the `match` isn't part of this String,
* 0 will be returned, else the index of match (1-based index)
*/
public int findInSet(UTF8String match) {
if (match.contains(COMMA_UTF8)) {
return 0;
}
int n = 1, lastComma = -1;
for (int i = 0; i < numBytes; i++) {
if (getByte(i) == (byte) ',') {
if (i - (lastComma + 1) == match.numBytes
&& ByteArrayMethods.arrayEquals(
base, offset + (lastComma + 1), match.base, match.offset, match.numBytes)) {
return n;
}
lastComma = i;
n++;
}
}
if (numBytes - (lastComma + 1) == match.numBytes
&& ByteArrayMethods.arrayEquals(
base, offset + (lastComma + 1), match.base, match.offset, match.numBytes)) {
return n;
}
return 0;
}
/**
* Levenshtein distance is a metric for measuring the distance of two strings. The distance is
* defined by the minimum number of single-character edits (i.e. insertions, deletions or
* substitutions) that are required to change one of the strings into the other.
*/
public int levenshteinDistance(UTF8String other) {
// Implementation adopted from org.apache.common.lang3.StringUtils.getLevenshteinDistance
int n = numChars();
int m = other.numChars();
if (n == 0) {
return m;
} else if (m == 0) {
return n;
}
UTF8String s, t;
if (n <= m) {
s = this;
t = other;
} else {
s = other;
t = this;
int swap;
swap = n;
n = m;
m = swap;
}
int[] p = new int[n + 1];
int[] d = new int[n + 1];
int[] swap;
int i, i_bytes, j, j_bytes, num_bytes_j, cost;
for (i = 0; i <= n; i++) {
p[i] = i;
}
for (j = 0, j_bytes = 0; j < m; j_bytes += num_bytes_j, j++) {
num_bytes_j = numBytesForFirstByte(t.getByte(j_bytes));
d[0] = j + 1;
for (i = 0, i_bytes = 0; i < n; i_bytes += numBytesForFirstByte(s.getByte(i_bytes)), i++) {
if (s.getByte(i_bytes) != t.getByte(j_bytes)
|| num_bytes_j != numBytesForFirstByte(s.getByte(i_bytes))) {
cost = 1;
} else {
cost =
(ByteArrayMethods.arrayEquals(
t.base, t.offset + j_bytes, s.base, s.offset + i_bytes, num_bytes_j))
? 0
: 1;
}
d[i + 1] = Math.min(Math.min(d[i] + 1, p[i + 1] + 1), p[i] + cost);
}
swap = p;
p = d;
d = swap;
}
return p[n];
}
/**
* Copy the bytes from the current UTF8String, and make a new UTF8String.
*
* @param start the start position of the current UTF8String in bytes.
* @param end the end position of the current UTF8String in bytes.
* @return a new UTF8String in the position of [start, end] of current UTF8String bytes.
*/
private UTF8String copyUTF8String(int start, int end) {
int len = end - start + 1;
byte[] newBytes = new byte[len];
copyMemory(base, offset + start, newBytes, BYTE_ARRAY_OFFSET, len);
return UTF8String.fromBytes(newBytes);
}
/**
* A UTF-8 String for internal Spark use.
*
* <p>A String encoded in UTF-8 as an Array[Byte], which can be used for comparison, search, see
* http://en.wikipedia.org/wiki/UTF-8 for details.
*
* <p>Note: This is not designed for general use cases, should not be used outside SQL.
*/
public final class UTF8String implements Comparable<UTF8String>, Externalizable, KryoSerializable {
// These are only updated by readExternal() or read()
@Nonnull private Object base;
private long offset;
private int numBytes;
public Object getBaseObject() {
return base;
}
public long getBaseOffset() {
return offset;
}
private static int[] bytesOfCodePointInUTF8 = {
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6
};
private static boolean isLittleEndian = ByteOrder.nativeOrder() == ByteOrder.LITTLE_ENDIAN;
private static final UTF8String COMMA_UTF8 = UTF8String.fromString(",");
public static final UTF8String EMPTY_UTF8 = UTF8String.fromString("");
/**
* Creates an UTF8String from byte array, which should be encoded in UTF-8.
*
* <p>Note: `bytes` will be hold by returned UTF8String.
*/
public static UTF8String fromBytes(byte[] bytes) {
if (bytes != null) {
return new UTF8String(bytes, BYTE_ARRAY_OFFSET, bytes.length);
} else {
return null;
}
}
/**
* Creates an UTF8String from byte array, which should be encoded in UTF-8.
*
* <p>Note: `bytes` will be hold by returned UTF8String.
*/
public static UTF8String fromBytes(byte[] bytes, int offset, int numBytes) {
if (bytes != null) {
return new UTF8String(bytes, BYTE_ARRAY_OFFSET + offset, numBytes);
} else {
return null;
}
}
/**
* Creates an UTF8String from given address (base and offset) and length.
*
* @param base baseObject,通常是字节数组
* @param offset 字符串的第一个字节在字节数组中的位置(它是针对字节数组的首位置的偏移量)
* @param numBytes 字符串占用的字节数
* @return
*/
public static UTF8String fromAddress(Object base, long offset, int numBytes) {
/** * 构造UTF8String,构造参数是base、offset、numBytes */
return new UTF8String(base, offset, numBytes);
}
/** Creates an UTF8String from String. */
public static UTF8String fromString(String str) {
if (str == null) return null;
try {
return fromBytes(str.getBytes("utf-8"));
} catch (UnsupportedEncodingException e) {
// Turn the exception into unchecked so we can find out about it at runtime, but
// don't need to add lots of boilerplate code everywhere.
throwException(e);
return null;
}
}
/** Creates an UTF8String that contains `length` spaces. */
public static UTF8String blankString(int length) {
byte[] spaces = new byte[length];
Arrays.fill(spaces, (byte) ' ');
return fromBytes(spaces);
}
/**
* * UTF8String的构造方法，是protected的，它有三个构造参数
*
* @param base 字符串的backing up字节数组
* @param offset 字符串数据在字节数组中的偏移量
* @param numBytes 字符串占用的字节长度
*/
protected UTF8String(Object base, long offset, int numBytes) {
this.base = base;
this.offset = offset;
this.numBytes = numBytes;
}
// for serialization
public UTF8String() {
this(null, 0, 0);
}
/**
* Writes the content of this string into a memory address, identified by an object and an offset.
* The target memory address must already been allocated, and have enough space to hold all the
* bytes in this string.
*/
public void writeToMemory(Object target, long targetOffset) {
Platform.copyMemory(base, offset, target, targetOffset, numBytes);
}
public void writeTo(ByteBuffer buffer) {
assert (buffer.hasArray());
byte[] target = buffer.array();
int offset = buffer.arrayOffset();
int pos = buffer.position();
writeToMemory(target, Platform.BYTE_ARRAY_OFFSET + offset + pos);
buffer.position(pos + numBytes);
}
/**
* Returns the number of bytes for a code point with the first byte as `b`
*
* @param b The first byte of a code point
*/
private static int numBytesForFirstByte(final byte b) {
final int offset = (b & 0xFF) - 192;
return (offset >= 0) ? bytesOfCodePointInUTF8[offset] : 1;
}
/** Returns the number of bytes */
public int numBytes() {
return numBytes;
}
/** Returns the number of code points in it. */
public int numChars() {
int len = 0;
for (int i = 0; i < numBytes; i += numBytesForFirstByte(getByte(i))) {
len += 1;
}
return len;
}
/** Returns a 64-bit integer that can be used as the prefix used in sorting. */
public long getPrefix() {
// Since JVMs are either 4-byte aligned or 8-byte aligned, we check the size of the string.
// If size is 0, just return 0.
// If size is between 0 and 4 (inclusive), assume data is 4-byte aligned under the hood and
// use a getInt to fetch the prefix.
// If size is greater than 4, assume we have at least 8 bytes of data to fetch.
// After getting the data, we use a mask to mask out data that is not part of the string.
long p;
long mask = 0;
if (isLittleEndian) {
if (numBytes >= 8) {
p = Platform.getLong(base, offset);
} else if (numBytes > 4) {
p = Platform.getLong(base, offset);
mask = (1L << (8 - numBytes) * 8) - 1;
} else if (numBytes > 0) {
p = (long) Platform.getInt(base, offset);
mask = (1L << (8 - numBytes) * 8) - 1;
} else {
p = 0;
}
p = java.lang.Long.reverseBytes(p);
} else {
// byteOrder == ByteOrder.BIG_ENDIAN
if (numBytes >= 8) {
p = Platform.getLong(base, offset);
} else if (numBytes > 4) {
p = Platform.getLong(base, offset);
mask = (1L << (8 - numBytes) * 8) - 1;
} else if (numBytes > 0) {
p = ((long) Platform.getInt(base, offset)) << 32;
mask = (1L << (8 - numBytes) * 8) - 1;
} else {
p = 0;
}
}
p &= ~mask;
return p;
}
/**
* Returns the underline bytes, will be a copy of it if it's part of another array.
* UTF8String字符串对应的字节数组
*/
public byte[] getBytes() {
// avoid copy if `base` is `byte[]`
// 如果整个base数组就只有这一个字符串，那么直接将该base数组返回
// base是否有BYTE_ARRAY_OFFSET的字节数浪费了？
if (offset == BYTE_ARRAY_OFFSET
&& base instanceof byte[]
&& ((byte[]) base).length == numBytes) {
return (byte[]) base;
}
// 复制长度为bytes的内存区域
else {
byte[] bytes = new byte[numBytes];
/** 从base数组的offset位置复制长度为numBytes字节到byte中？bytes从BYTE_ARRAY_OFFSET位置开始copy？ */
copyMemory(base, offset, bytes, BYTE_ARRAY_OFFSET, numBytes);
return bytes;
}
}
/**
* Returns a substring of this.
*
* @param start the position of first code point
* @param until the position after last code point, exclusive.
*/
public UTF8String substring(final int start, final int until) {
if (until <= start || start >= numBytes) {
return EMPTY_UTF8;
}
int i = 0;
int c = 0;
while (i < numBytes && c < start) {
i += numBytesForFirstByte(getByte(i));
c += 1;
}
int j = i;
while (i < numBytes && c < until) {
i += numBytesForFirstByte(getByte(i));
c += 1;
}
if (i > j) {
byte[] bytes = new byte[i - j];
copyMemory(base, offset + j, bytes, BYTE_ARRAY_OFFSET, i - j);
return fromBytes(bytes);
} else {
return EMPTY_UTF8;
}
}
public UTF8String substringSQL(int pos, int length) {
// Information regarding the pos calculation:
// Hive and SQL use one-based indexing for SUBSTR arguments but also accept zero and
// negative indices for start positions. If a start index i is greater than 0, it
// refers to element i-1 in the sequence. If a start index i is less than 0, it refers
// to the -ith element before the end of the sequence. If a start index i is 0, it
// refers to the first element.
int len = numChars();
int start = (pos > 0) ? pos - 1 : ((pos < 0) ? len + pos : 0);
int end = (length == Integer.MAX_VALUE) ? len : start + length;
return substring(start, end);
}
/** Returns whether this contains `substring` or not. */
public boolean contains(final UTF8String substring) {
if (substring.numBytes == 0) {
return true;
}
byte first = substring.getByte(0);
for (int i = 0; i <= numBytes - substring.numBytes; i++) {
if (getByte(i) == first && matchAt(substring, i)) {
return true;
}
}
return false;
}
/** Returns the byte at position `i`. */
private byte getByte(int i) {
return Platform.getByte(base, offset + i);
}
private boolean matchAt(final UTF8String s, int pos) {
if (s.numBytes + pos > numBytes || pos < 0) {
return false;
}
return ByteArrayMethods.arrayEquals(base, offset + pos, s.base, s.offset, s.numBytes);
}
public boolean startsWith(final UTF8String prefix) {
return matchAt(prefix, 0);
}
public boolean endsWith(final UTF8String suffix) {
return matchAt(suffix, numBytes - suffix.numBytes);
}
/** Returns the upper case of this string */
public UTF8String toUpperCase() {
if (numBytes == 0) {
return EMPTY_UTF8;
}
byte[] bytes = new byte[numBytes];
bytes[0] = (byte) Character.toTitleCase(getByte(0));
for (int i = 0; i < numBytes; i++) {
byte b = getByte(i);
if (numBytesForFirstByte(b) != 1) {
// fallback
return toUpperCaseSlow();
}
int upper = Character.toUpperCase((int) b);
if (upper > 127) {
// fallback
return toUpperCaseSlow();
}
bytes[i] = (byte) upper;
}
return fromBytes(bytes);
}
private UTF8String toUpperCaseSlow() {
return fromString(toString().toUpperCase());
}
/** Returns the lower case of this string */
public UTF8String toLowerCase() {
if (numBytes == 0) {
return EMPTY_UTF8;
}
byte[] bytes = new byte[numBytes];
bytes[0] = (byte) Character.toTitleCase(getByte(0));
for (int i = 0; i < numBytes; i++) {
byte b = getByte(i);
if (numBytesForFirstByte(b) != 1) {
// fallback
return toLowerCaseSlow();
}
int lower = Character.toLowerCase((int) b);
if (lower > 127) {
// fallback
return toLowerCaseSlow();
}
bytes[i] = (byte) lower;
}
return fromBytes(bytes);
}
private UTF8String toLowerCaseSlow() {
return fromString(toString().toLowerCase());
}
/** Returns the title case of this string, that could be used as title. */
public UTF8String toTitleCase() {
if (numBytes == 0) {
return EMPTY_UTF8;
}
byte[] bytes = new byte[numBytes];
for (int i = 0; i < numBytes; i++) {
byte b = getByte(i);
if (i == 0 || getByte(i - 1) == ' ') {
if (numBytesForFirstByte(b) != 1) {
// fallback
return toTitleCaseSlow();
}
int upper = Character.toTitleCase(b);
if (upper > 127) {
// fallback
return toTitleCaseSlow();
}
bytes[i] = (byte) upper;
} else {
bytes[i] = b;
}
}
return fromBytes(bytes);
}
private UTF8String toTitleCaseSlow() {
StringBuffer sb = new StringBuffer();
String s = toString();
sb.append(s);
sb.setCharAt(0, Character.toTitleCase(sb.charAt(0)));
for (int i = 1; i < s.length(); i++) {
if (sb.charAt(i - 1) == ' ') {
sb.setCharAt(i, Character.toTitleCase(sb.charAt(i)));
}
}
return fromString(sb.toString());
}
/*
* Returns the index of the string `match` in this String. This string has to be a comma separated
* list. If `match` contains a comma 0 will be returned. If the `match` isn't part of this String,
* 0 will be returned, else the index of match (1-based index)
*/
public int findInSet(UTF8String match) {
if (match.contains(COMMA_UTF8)) {
return 0;
}
int n = 1, lastComma = -1;
for (int i = 0; i < numBytes; i++) {
if (getByte(i) == (byte) ',') {
if (i - (lastComma + 1) == match.numBytes
&& ByteArrayMethods.arrayEquals(
base, offset + (lastComma + 1), match.base, match.offset, match.numBytes)) {
return n;
}
lastComma = i;
n++;
}
}
if (numBytes - (lastComma + 1) == match.numBytes
&& ByteArrayMethods.arrayEquals(
base, offset + (lastComma + 1), match.base, match.offset, match.numBytes)) {
return n;
}
return 0;
}
/**
* Copy the bytes from the current UTF8String, and make a new UTF8String.
*
* @param start the start position of the current UTF8String in bytes.
* @param end the end position of the current UTF8String in bytes.
* @return a new UTF8String in the position of [start, end] of current UTF8String bytes.
*/
private UTF8String copyUTF8String(int start, int end) {
int len = end - start + 1;
byte[] newBytes = new byte[len];
copyMemory(base, offset + start, newBytes, BYTE_ARRAY_OFFSET, len);
return UTF8String.fromBytes(newBytes);
}
public UTF8String trim() {
int s = 0;
int e = this.numBytes - 1;
// skip all of the space (0x20) in the left side
while (s < this.numBytes && getByte(s) <= 0x20 && getByte(s) >= 0x00) s++;
// skip all of the space (0x20) in the right side
while (e >= 0 && getByte(e) <= 0x20 && getByte(e) >= 0x00) e--;
if (s > e) {
// empty string
return UTF8String.fromBytes(new byte[0]);
} else {
return copyUTF8String(s, e);
}
}
public UTF8String trimLeft() {
int s = 0;
// skip all of the space (0x20) in the left side
while (s < this.numBytes && getByte(s) <= 0x20 && getByte(s) >= 0x00) s++;
if (s == this.numBytes) {
// empty string
return UTF8String.fromBytes(new byte[0]);
} else {
return copyUTF8String(s, this.numBytes - 1);
}
}
public UTF8String trimRight() {
int e = numBytes - 1;
// skip all of the space (0x20) in the right side
while (e >= 0 && getByte(e) <= 0x20 && getByte(e) >= 0x00) e--;
if (e < 0) {
// empty string
return UTF8String.fromBytes(new byte[0]);
} else {
return copyUTF8String(0, e);
}
}
public UTF8String reverse() {
byte[] result = new byte[this.numBytes];
int i = 0; // position in byte
while (i < numBytes) {
int len = numBytesForFirstByte(getByte(i));
copyMemory(
this.base, this.offset + i, result, BYTE_ARRAY_OFFSET + result.length - i - len, len);
i += len;
}
return UTF8String.fromBytes(result);
}
public UTF8String repeat(int times) {
if (times <= 0) {
return EMPTY_UTF8;
}
byte[] newBytes = new byte[numBytes * times];
copyMemory(this.base, this.offset, newBytes, BYTE_ARRAY_OFFSET, numBytes);
int copied = 1;
while (copied < times) {
int toCopy = Math.min(copied, times - copied);
System.arraycopy(newBytes, 0, newBytes, copied * numBytes, numBytes * toCopy);
copied += toCopy;
}
return UTF8String.fromBytes(newBytes);
}
/**
* Returns the position of the first occurrence of substr in current string from the specified
* position (0-based index).
*
* @param v the string to be searched
* @param start the start position of the current string for searching
* @return the position of the first occurrence of substr, if not found, -1 returned.
*/
public int indexOf(UTF8String v, int start) {
if (v.numBytes() == 0) {
return 0;
}
// locate to the start position.
int i = 0; // position in byte
int c = 0; // position in character
while (i < numBytes && c < start) {
i += numBytesForFirstByte(getByte(i));
c += 1;
}
do {
if (i + v.numBytes > numBytes) {
return -1;
}
if (ByteArrayMethods.arrayEquals(base, offset + i, v.base, v.offset, v.numBytes)) {
return c;
}
i += numBytesForFirstByte(getByte(i));
c += 1;
} while (i < numBytes);
return -1;
}
/** Find the `str` from left to right. */
private int find(UTF8String str, int start) {
assert (str.numBytes > 0);
while (start <= numBytes - str.numBytes) {
if (ByteArrayMethods.arrayEquals(base, offset + start, str.base, str.offset, str.numBytes)) {
return start;
}
start += 1;
}
return -1;
}
/** Find the `str` from right to left. */
private int rfind(UTF8String str, int start) {
assert (str.numBytes > 0);
while (start >= 0) {
if (ByteArrayMethods.arrayEquals(base, offset + start, str.base, str.offset, str.numBytes)) {
return start;
}
start -= 1;
}
return -1;
}
/**
* Returns the substring from string str before count occurrences of the delimiter delim. If count
* is positive, everything the left of the final delimiter (counting from left) is returned. If
* count is negative, every to the right of the final delimiter (counting from the right) is
* returned. subStringIndex performs a case-sensitive match when searching for delim.
*/
public UTF8String subStringIndex(UTF8String delim, int count) {
if (delim.numBytes == 0 || count == 0) {
return EMPTY_UTF8;
}
if (count > 0) {
int idx = -1;
while (count > 0) {
idx = find(delim, idx + 1);
if (idx >= 0) {
count--;
} else {
// can not find enough delim
return this;
}
}
if (idx == 0) {
return EMPTY_UTF8;
}
byte[] bytes = new byte[idx];
copyMemory(base, offset, bytes, BYTE_ARRAY_OFFSET, idx);
return fromBytes(bytes);
} else {
int idx = numBytes - delim.numBytes + 1;
count = -count;
while (count > 0) {
idx = rfind(delim, idx - 1);
if (idx >= 0) {
count--;
} else {
// can not find enough delim
return this;
}
}
if (idx + delim.numBytes == numBytes) {
return EMPTY_UTF8;
}
int size = numBytes - delim.numBytes - idx;
byte[] bytes = new byte[size];
copyMemory(base, offset + idx + delim.numBytes, bytes, BYTE_ARRAY_OFFSET, size);
return fromBytes(bytes);
}
}
/**
* Returns str, right-padded with pad to a length of len For example: ('hi', 5, '??') =>
* 'hi???' ('hi', 1, '??') => 'h'
*/
public UTF8String rpad(int len, UTF8String pad) {
int spaces = len - this.numChars(); // number of char need to pad
if (spaces <= 0 || pad.numBytes() == 0) {
// no padding at all, return the substring of the current string
return substring(0, len);
} else {
int padChars = pad.numChars();
int count = spaces / padChars; // how many padding string needed
// the partial string of the padding
UTF8String remain = pad.substring(0, spaces - padChars * count);
byte[] data = new byte[this.numBytes + pad.numBytes * count + remain.numBytes];
copyMemory(this.base, this.offset, data, BYTE_ARRAY_OFFSET, this.numBytes);
int offset = this.numBytes;
int idx = 0;
while (idx < count) {
copyMemory(pad.base, pad.offset, data, BYTE_ARRAY_OFFSET + offset, pad.numBytes);
++idx;
offset += pad.numBytes;
}
copyMemory(remain.base, remain.offset, data, BYTE_ARRAY_OFFSET + offset, remain.numBytes);
return UTF8String.fromBytes(data);
}
}
/**
* Returns str, left-padded with pad to a length of len. For example: ('hi', 5, '??') =>
* '???hi' ('hi', 1, '??') => 'h'
*/
public UTF8String lpad(int len, UTF8String pad) {
int spaces = len - this.numChars(); // number of char need to pad
if (spaces <= 0 || pad.numBytes() == 0) {
// no padding at all, return the substring of the current string
return substring(0, len);
} else {
int padChars = pad.numChars();
int count = spaces / padChars; // how many padding string needed
// the partial string of the padding
UTF8String remain = pad.substring(0, spaces - padChars * count);
byte[] data = new byte[this.numBytes + pad.numBytes * count + remain.numBytes];
int offset = 0;
int idx = 0;
while (idx < count) {
copyMemory(pad.base, pad.offset, data, BYTE_ARRAY_OFFSET + offset, pad.numBytes);
++idx;
offset += pad.numBytes;
}
copyMemory(remain.base, remain.offset, data, BYTE_ARRAY_OFFSET + offset, remain.numBytes);
offset += remain.numBytes;
copyMemory(this.base, this.offset, data, BYTE_ARRAY_OFFSET + offset, numBytes());
return UTF8String.fromBytes(data);
}
}
/**
* Concatenates input strings together into a single string. Returns null if any input is null.
*/
public static UTF8String concat(UTF8String... inputs) {
// Compute the total length of the result.
int totalLength = 0;
for (int i = 0; i < inputs.length; i++) {
if (inputs[i] != null) {
totalLength += inputs[i].numBytes;
} else {
return null;
}
}
// Allocate a new byte array, and copy the inputs one by one into it.
final byte[] result = new byte[totalLength];
int offset = 0;
for (int i = 0; i < inputs.length; i++) {
int len = inputs[i].numBytes;
copyMemory(inputs[i].base, inputs[i].offset, result, BYTE_ARRAY_OFFSET + offset, len);
offset += len;
}
return fromBytes(result);
}
/**
* Concatenates input strings together into a single string using the separator. A null input is
* skipped. For example, concat(",", "a", null, "c") would yield "a,c".
*/
public static UTF8String concatWs(UTF8String separator, UTF8String... inputs) {
if (separator == null) {
return null;
}
int numInputBytes = 0; // total number of bytes from the inputs
int numInputs = 0; // number of non-null inputs
for (int i = 0; i < inputs.length; i++) {
if (inputs[i] != null) {
numInputBytes += inputs[i].numBytes;
numInputs++;
}
}
if (numInputs == 0) {
// Return an empty string if there is no input, or all the inputs are null.
return fromBytes(new byte[0]);
}
// Allocate a new byte array, and copy the inputs one by one into it.
// The size of the new array is the size of all inputs, plus the separators.
final byte[] result = new byte[numInputBytes + (numInputs - 1) * separator.numBytes];
int offset = 0;
for (int i = 0, j = 0; i < inputs.length; i++) {
if (inputs[i] != null) {
int len = inputs[i].numBytes;
copyMemory(inputs[i].base, inputs[i].offset, result, BYTE_ARRAY_OFFSET + offset, len);
offset += len;
j++;
// Add separator if this is not the last input.
if (j < numInputs) {
copyMemory(
separator.base,
separator.offset,
result,
BYTE_ARRAY_OFFSET + offset,
separator.numBytes);
offset += separator.numBytes;
}
}
}
return fromBytes(result);
}
public UTF8String[] split(UTF8String pattern, int limit) {
String[] splits = toString().split(pattern.toString(), limit);
UTF8String[] res = new UTF8String[splits.length];
for (int i = 0; i < res.length; i++) {
res[i] = fromString(splits[i]);
}
return res;
}
// TODO: Need to use `Code Point` here instead of Char in case the character longer than 2 bytes
public UTF8String translate(Map<Character, Character> dict) {
String srcStr = this.toString();
StringBuilder sb = new StringBuilder();
for (int k = 0; k < srcStr.length(); k++) {
if (null == dict.get(srcStr.charAt(k))) {
sb.append(srcStr.charAt(k));
} else if ('\0' != dict.get(srcStr.charAt(k))) {
sb.append(dict.get(srcStr.charAt(k)));
}
}
return fromString(sb.toString());
}
@Override
public String toString() {
try {
return new String(getBytes(), "utf-8");
} catch (UnsupportedEncodingException e) {
// Turn the exception into unchecked so we can find out about it at runtime, but
// don't need to add lots of boilerplate code everywhere.
throwException(e);
return "unknown"; // we will never reach here.
}
}
@Override
public UTF8String clone() {
return fromBytes(getBytes());
}
@Override
public int compareTo(@Nonnull final UTF8String other) {
int len = Math.min(numBytes, other.numBytes);
// TODO: compare 8 bytes as unsigned long
for (int i = 0; i < len; i++) {
// In UTF-8, the byte should be unsigned, so we should compare them as unsigned int.
int res = (getByte(i) & 0xFF) - (other.getByte(i) & 0xFF);
if (res != 0) {
return res;
}
}
return numBytes - other.numBytes;
}
public int compare(final UTF8String other) {
return compareTo(other);
}
@Override
public boolean equals(final Object other) {
if (other instanceof UTF8String) {
UTF8String o = (UTF8String) other;
if (numBytes != o.numBytes) {
return false;
}
return ByteArrayMethods.arrayEquals(base, offset, o.base, o.offset, numBytes);
} else {
return false;
}
}
/**
* Levenshtein distance is a metric for measuring the distance of two strings. The distance is
* defined by the minimum number of single-character edits (i.e. insertions, deletions or
* substitutions) that are required to change one of the strings into the other.
*/
public int levenshteinDistance(UTF8String other) {
// Implementation adopted from org.apache.common.lang3.StringUtils.getLevenshteinDistance
int n = numChars();
int m = other.numChars();
if (n == 0) {
return m;
} else if (m == 0) {
return n;
}
UTF8String s, t;
if (n <= m) {
s = this;
t = other;
} else {
s = other;
t = this;
int swap;
swap = n;
n = m;
m = swap;
}
int[] p = new int[n + 1];
int[] d = new int[n + 1];
int[] swap;
int i, i_bytes, j, j_bytes, num_bytes_j, cost;
for (i = 0; i <= n; i++) {
p[i] = i;
}
for (j = 0, j_bytes = 0; j < m; j_bytes += num_bytes_j, j++) {
num_bytes_j = numBytesForFirstByte(t.getByte(j_bytes));
d[0] = j + 1;
for (i = 0, i_bytes = 0; i < n; i_bytes += numBytesForFirstByte(s.getByte(i_bytes)), i++) {
if (s.getByte(i_bytes) != t.getByte(j_bytes)
|| num_bytes_j != numBytesForFirstByte(s.getByte(i_bytes))) {
cost = 1;
} else {
cost =
(ByteArrayMethods.arrayEquals(
t.base, t.offset + j_bytes, s.base, s.offset + i_bytes, num_bytes_j))
? 0
: 1;
}
d[i + 1] = Math.min(Math.min(d[i] + 1, p[i + 1] + 1), p[i] + cost);
}
swap = p;
p = d;
d = swap;
}
return p[n];
}
@Override
public int hashCode() {
return Murmur3_x86_32.hashUnsafeBytes(base, offset, numBytes, 42);
}
/** Soundex mapping table */
private static final byte[] US_ENGLISH_MAPPING = {
'0', '1', '2', '3', '0', '1', '2', '7', '0', '2', '2', '4', '5', '5', '0', '1', '2', '6', '2',
'3', '0', '1', '7', '2', '0', '2'
};
/**
* Encodes a string into a Soundex value. Soundex is an encoding used to relate similar names, but
* can also be used as a general purpose scheme to find word with similar phonemes.
* https://en.wikipedia.org/wiki/Soundex
*/
public UTF8String soundex() {
if (numBytes == 0) {
return EMPTY_UTF8;
}
byte b = getByte(0);
if ('a' <= b && b <= 'z') {
b -= 32;
} else if (b < 'A' || 'Z' < b) {
// first character must be a letter
return this;
}
byte[] sx = {'0', '0', '0', '0'};
sx[0] = b;
int sxi = 1;
int idx = b - 'A';
byte lastCode = US_ENGLISH_MAPPING[idx];
for (int i = 1; i < numBytes; i++) {
b = getByte(i);
if ('a' <= b && b <= 'z') {
b -= 32;
} else if (b < 'A' || 'Z' < b) {
// not a letter, skip it
lastCode = '0';
continue;
}
idx = b - 'A';
byte code = US_ENGLISH_MAPPING[idx];
if (code == '7') {
// ignore it
} else {
if (code != '0' && code != lastCode) {
sx[sxi++] = code;
if (sxi > 3) break;
}
lastCode = code;
}
}
return UTF8String.fromBytes(sx);
}
public void writeExternal(ObjectOutput out) throws IOException {
byte[] bytes = getBytes();
out.writeInt(bytes.length);
out.write(bytes);
}
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
offset = BYTE_ARRAY_OFFSET;
numBytes = in.readInt();
base = new byte[numBytes];
in.readFully((byte[]) base);
}
@Override
public void write(Kryo kryo, Output out) {
byte[] bytes = getBytes();
out.writeInt(bytes.length);
out.write(bytes);
}
@Override
public void read(Kryo kryo, Input in) {
this.offset = BYTE_ARRAY_OFFSET;
this.numBytes = in.readInt();
this.base = new byte[numBytes];
in.read((byte[]) base);
}
}