software.coley.llzip.util.ByteDataUtil Maven / Gradle / Ivy
package software.coley.llzip.util;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.Objects;
/**
* Buffer utils.
*
* @author Matt Coley
*/
public class ByteDataUtil {
public static final int WILDCARD = Integer.MIN_VALUE;
/**
* @param data
* Content to search.
* @param offset
* Offset to begin search at.
* @param pattern
* Pattern to match.
*
* @return First index of pattern in content, or {@code -1} for no match.
*/
public static long indexOfWord(ByteData data, long offset, int pattern) {
long len = data.length() - 2;
for (long i = offset; i < len; i++) {
if (pattern == data.getShort(i))
return i;
}
return -1;
}
/**
* @param data
* Content to search.
* @param offset
* Offset to begin search at.
* @param pattern
* Pattern to match.
*
* @return First index of pattern in content, or {@code -1} for no match.
*/
public static long indexOfQuad(ByteData data, long offset, int pattern) {
long len = data.length() - 4;
long i = offset;
while (i < len) {
int value = data.getInt(i);
if (pattern == value)
return i;
// Move i forwards as far as possible, where we can assume that distance
// will never contain a match.
if ((pattern & 0xFF_FF_FF) == ((value & 0xFF_FF_FF_00) >>> 8)) {
i += 1;
} else if ((pattern & 0xFF_FF) == ((value & 0xFF_FF_00_00) >>> 16)) {
i += 2;
} else if ((pattern & 0xFF) == ((value & 0xFF_00_00_00)) >>> 24) {
i += 3;
} else {
i += 4;
}
}
return -1;
}
/**
* @param data
* Content to search.
* @param offset
* Offset to begin search at.
* @param pattern
* Pattern to match.
*
* @return Last index of pattern in content, or {@code -1} for no match.
*/
public static long lastIndexOfWord(ByteData data, long offset, int pattern) {
long limit;
if (data == null || (limit = data.length()) < 2 || offset >= limit)
return -1;
for (long i = offset; i >= 0; i--) {
if (pattern == data.getShort(i))
return i;
}
return -1;
}
/**
* @param data
* Content to search.
* @param offset
* Offset to begin search at.
* @param pattern
* Pattern to match.
*
* @return Last index of pattern in content, or {@code -1} for no match.
*/
public static long lastIndexOfQuad(ByteData data, long offset, int pattern) {
long limit;
if (data == null || (limit = data.length()) < 4 || offset >= limit)
return -1;
long i = offset;
while (i >= 0) {
int value = data.getInt(i);
if (pattern == value)
return i;
// Move i backwards as far back as possible, where we can assume that distance
// will never contain a match.
if (((pattern & 0xFF_FF_FF_00) >>> 8) == (value & 0x00_FF_FF_FF)) {
i -= 1;
} else if (((pattern & 0xFF_FF_00_00) >>> 16) == (value & 0x00_00_FF_FF)) {
i -= 2;
} else if (((pattern & 0xFF_FF_FF_00) >>> 24) == (value & 0x00_00_00_FF)) {
i -= 3;
} else {
i -= 4;
}
}
return -1;
}
/**
* @param data
* Content to search.
* @param pattern
* Pattern to match.
*
* @return First index of pattern in content, or {@code -1} for no match.
*/
public static long indexOf(ByteData data, int[] pattern) {
return indexOf(data, 0, pattern);
}
/**
* @param data
* Content to search.
* @param offset
* Offset to begin search at.
* @param pattern
* Pattern to match.
*
* @return First index of pattern in content, or {@code -1} for no match.
*/
public static long indexOf(ByteData data, long offset, int[] pattern) {
// Remaining data must be as long as pattern
long limit;
if (data == null || (limit = data.length()) < pattern.length || offset >= limit)
return -1;
// Search from offset going forwards
for (long i = offset; i < limit; i++)
if (startsWith(data, i, pattern))
return i;
// Not found
return -1;
}
/**
* @param data
* Content to search.
* @param pattern
* Pattern to match.
*
* @return Last index of pattern in content, or {@code -1} for no match.
*/
public static long lastIndexOf(ByteData data, int[] pattern) {
return lastIndexOf(data, (data.length() - pattern.length), pattern);
}
/**
* @param data
* Content to search.
* @param offset
* Offset to begin search at.
* @param pattern
* Pattern to match.
*
* @return Last index of pattern in content, or {@code -1} for no match.
*/
public static long lastIndexOf(ByteData data, long offset, int[] pattern) {
// Remaining data must be as long as pattern
if (data == null || data.length() < pattern.length)
return -1;
// Search from offset going backwards
for (long i = offset; i >= 0; i--)
if (startsWith(data, i, pattern))
return i;
// Not found
return -1;
}
/**
* @param data
* Content to search.
* @param offset
* Offset to begin check at.
* @param pattern
* Pattern to match.
*
* @return {@code true} when the content of the array at the offset matches the pattern.
*/
public static boolean startsWith(ByteData data, long offset, int[] pattern) {
// Remaining data must be as long as pattern and in the array bounds
if (data == null || (data.length() - offset) < pattern.length || offset < 0 || offset >= data.length())
return false;
// Check for mis-match
for (int i = 0; i < pattern.length; i++) {
int p = pattern[i];
if (p == WILDCARD)
continue;
if (data.get(offset + i) != p)
return false;
}
// No mis-match, array starts with pattern
return true;
}
/**
* @param data
* Content to read from.
* @param i
* Index to read word from.
*
* @return Value of word.
*/
public static int readWord(ByteData data, long i) {
return data.getShort(i) & 0xFFFF;
}
/**
* @param data
* Content to read from.
* @param i
* Index to read quad from.
*
* @return Value of quad.
*/
public static int readQuad(ByteData data, long i) {
return data.getInt(i);
}
/**
* @param data
* Content to read from.
* @param start
* Start position of string.
* @param len
* Length of string.
*
* @return Value of string.
*/
public static String readString(ByteData data, long start, int len) {
if (len == 0)
return "";
byte[] bytes = new byte[len];
data.get(start, bytes, 0, len);
return new String(bytes, StandardCharsets.UTF_8);
}
/**
* @param data
* Content to read from.
* @param start
* Start index.
* @param len
* Length of content to copy.
*
* @return Copy of range.
*/
public static byte[] readArray(ByteData data, int start, int len) {
byte[] bytes = new byte[len];
data.get(start, bytes, 0, len);
return bytes;
}
/**
* @param data
* Content to make slice of.
* @param start
* Start index.
* @param end
* Endex index.
*
* @return Buffer slice.
*/
public static ByteBuffer sliceExact(ByteBuffer data, int start, int end) {
ByteBuffer slice = data.slice();
slice = ((ByteBuffer) slice.position(start)).slice();
slice.limit(end - start);
return slice.order(data.order());
}
/**
* @param data
* Content to make slice of.
* @param start
* Start index.
* @param len
* Length of content to make slice of.
*
* @return Buffer slice.
*/
public static ByteData slice(ByteData data, long start, long len) {
return data.slice(start, start + len);
}
/**
* @param data
* Content to get length of.
*
* @return Buffer length.
*/
public static int length(ByteBuffer data) {
return data.remaining() - data.position();
}
/**
* @param data
* Content to get bytes from.
*
* @return Buffer as byte array.
*/
public static byte[] toByteArray(ByteData data) {
long length = data.length();
if (length > Integer.MAX_VALUE - 8) {
throw new IllegalStateException("Data too big!");
}
byte[] bytes = new byte[(int) length];
data.get(0L, bytes, 0, bytes.length);
return bytes;
}
/**
* @param data
* Content to convert to string to.
*
* @return Buffer as a string.
*/
public static String toString(ByteData data) {
return new String(toByteArray(data), StandardCharsets.UTF_8);
}
/**
* @param a
* First buffer.
* @param b
* Second buffer.
*
* @return {@code true} if buffers are equal.
*/
public static boolean equals(ByteData a, ByteData b) {
return Objects.equals(a, b);
}
}
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