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Hex calculations now support start/length, so hex values can be for a range of bytes. 

Optimized how hex encoding works
master
Robinson 2023-07-13 22:56:38 +02:00
parent d79550ef93
commit d176b43eff
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2 changed files with 72 additions and 27 deletions
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67
src/dorkbox/bytes/HexExtensions.kt
View File

@ -51,8 +51,9 @@ object Hex {
/**
* Represents all the chars used for nibble
*/
private const val CHARS = "0123456789abcdef"
private const val CHARS_UPPER = "0123456789ABCDEF"
private val HEX_CHARS = charArrayOf('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f')
private val UPPER_HEX_CHARS = charArrayOf('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F')
internal val HEX_REGEX = Regex("(0[xX])?[0-9a-fA-F]*")
@ -60,14 +61,24 @@ object Hex {
* Encodes the given byte value as a hexadecimal character.
*/
fun encode(value: Byte): String {
return CHARS[value.toInt().shr(4) and 0x0f].toString() + CHARS[value.toInt().and(0x0f)].toString()
val hexString = CharArray(2)
val toInt = value.toInt()
hexString[0] = HEX_CHARS[toInt and 0xF0 shr 4]
hexString[1] = HEX_CHARS[toInt and 0x0F]
return String(hexString)
}
/**
* Encodes the given byte value as a hexadecimal character.
*/
fun encodeUpper(value: Byte): String {
return CHARS_UPPER[value.toInt().shr(4) and 0x0f].toString() + CHARS_UPPER[value.toInt().and(0x0f)].toString()
val hexString = CharArray(2)
val toInt = value.toInt()
hexString[0] = UPPER_HEX_CHARS[toInt and 0xF0 shr 4]
hexString[1] = UPPER_HEX_CHARS[toInt and 0x0F]
return String(hexString)
}
/**
@ -76,16 +87,40 @@ object Hex {
* Note that by default the 0x prefix is prepended to the result of the conversion.
* If you want to have the representation without the 0x prefix, pass to this method an empty prefix.
*/
fun encode(value: ByteArray, prefix: String = "0x", limit: Int = value.size, toUpperCase: Boolean = false): String {
return if (toUpperCase) {
prefix + value.joinToString(separator = "", limit = limit, truncated = "") { encodeUpper(it) }
} else {
prefix + value.joinToString(separator = "", limit = limit, truncated = "") { encode(it) }
fun encode(bytes: ByteArray, prefix: String = "0x", start: Int = 0, length: Int = bytes.size, toUpperCase: Boolean = false): String {
require(start >= 0) { "Start ($start) must be >= 0" }
require(length >= 0) { "Limit ($length) must be >= 0" }
require(bytes.isEmpty() || start < bytes.size) { "Start ($start) position must be smaller than the size of the byte array" }
@Suppress("NAME_SHADOWING")
val length = if (length < bytes.size) length else bytes.size
val hexString = CharArray(prefix.length + ((2 * (length - start) )))
if (prefix.isNotEmpty()) {
prefix.toCharArray().copyInto(hexString)
}
var j = prefix.length
if (toUpperCase) {
for (i in start until length) {
val toInt = bytes[i].toInt()
hexString[j++] = UPPER_HEX_CHARS[toInt and 0xF0 shr 4]
hexString[j++] = UPPER_HEX_CHARS[toInt and 0x0F]
}
} else {
for (i in start until length) {
val toInt = bytes[i].toInt()
hexString[j++] = HEX_CHARS[toInt and 0xF0 shr 4]
hexString[j++] = HEX_CHARS[toInt and 0x0F]
}
}
return String(hexString)
}
/**
* Converts the given ch into its integer representation considering it as an hexadecimal character.
* Converts the given ch into its integer representation considering it as a hexadecimal character.
*/
private fun hexToBin(ch: Char): Int = when (ch) {
in '0'..'9' -> ch - '0'
@ -107,8 +142,8 @@ object Hex {
throw IllegalArgumentException("hex-string must have an even number of digits (nibbles)")
}
// Remove the 0x prefix if it is set
val cleanInput = if (value.startsWith("0x")) value.substring(2) else value
// Remove the 0x or 0X prefix if it is set
val cleanInput = if (value.startsWith("0x") || value.startsWith("0X")) value.substring(2) else value
return ByteArray(cleanInput.length / 2).apply {
var i = 0
@ -127,12 +162,12 @@ object Hex {
* If you want to have the representation without the 0x prefix, use the [toNoPrefixHexString] method or
* pass to this method an empty [prefix].
*/
fun ByteArray.toHexString(prefix: String = "0x", limit: Int = this.size, toUpperCase: Boolean = false): String = Hex.encode(this, prefix, limit, toUpperCase)
fun ByteArray.toHexString(prefix: String = "0x", start: Int = 0, length: Int = this.size, toUpperCase: Boolean = false): String = Hex.encode(this, prefix, start, length, toUpperCase)
/**
* Converts [this] [ByteArray] into its hexadecimal representation without prepending any prefix to it.
*/
fun ByteArray.toNoPrefixHexString(limit: Int = this.size, toUpperCase: Boolean = false): String = Hex.encode(this, "", limit, toUpperCase)
fun ByteArray.toNoPrefixHexString(start: Int = 0, length: Int = this.size, toUpperCase: Boolean = false): String = Hex.encode(this, "", start, length, toUpperCase)
/**
@ -142,12 +177,12 @@ fun ByteArray.toNoPrefixHexString(limit: Int = this.size, toUpperCase: Boolean =
* If you want to have the representation without the 0x prefix, use the [toNoPrefixHexString] method or
* pass to this method an empty [prefix].
*/
fun Collection<Byte>.toHexString(prefix: String = "0x", limit: Int = this.size): String = Hex.encode(this.toByteArray(), prefix, limit)
fun Collection<Byte>.toHexString(prefix: String = "0x", length: Int = this.size): String = Hex.encode(this.toByteArray(), prefix, length)
/**
* Converts [this] [Collection] of bytes into its hexadecimal representation without prepending any prefix to it.
*/
fun Collection<Byte>.toNoPrefixHexString(limit: Int = this.size): String = Hex.encode(this.toByteArray(), "", limit)
fun Collection<Byte>.toNoPrefixHexString(length: Int = this.size): String = Hex.encode(this.toByteArray(), "", length)
/**

32
test/dorkbox/bytes/TestHex.kt
View File

@ -54,17 +54,27 @@ class TestHex {
@Test
fun byteArrayLimitWorks() {
assertEquals("0x", Hex.encode(Hex.decode("00"), limit = 0))
assertEquals("0x00", Hex.encode(Hex.decode("00"), limit = 1))
assertEquals("0x", Hex.encode(Hex.decode("ff"), limit = 0))
assertEquals("0xff", Hex.encode(Hex.decode("ff"), limit = 1))
assertEquals("0x", Hex.encode(Hex.decode("abcdef"), limit = 0))
assertEquals("0xab", Hex.encode(Hex.decode("abcdef"), limit = 1))
assertEquals("0xabcd", Hex.encode(Hex.decode("abcdef"), limit = 2))
assertEquals("0xabcdef", Hex.encode(Hex.decode("abcdef"), limit = 3))
assertEquals("0xabcdef", Hex.encode(Hex.decode("abcdef"), limit = 32))
assertEquals("0xaa12456789bb", Hex.encode(Hex.decode("0xaa12456789bb"), limit = 6))
assertEquals("0xaa12456789bb", Hex.encode(Hex.decode("0xaa12456789bb"), limit = 9))
assertEquals("0x", Hex.encode(Hex.decode("00"), length = 0))
assertEquals("0x00", Hex.encode(Hex.decode("00"), length = 1))
assertEquals("0x", Hex.encode(Hex.decode("ff"), length = 0))
assertEquals("0xff", Hex.encode(Hex.decode("ff"), length = 1))
assertEquals("0x", Hex.encode(Hex.decode("abcdef"), length = 0))
assertEquals("0xab", Hex.encode(Hex.decode("abcdef"), length = 1))
assertEquals("0xabcd", Hex.encode(Hex.decode("abcdef"), length = 2))
assertEquals("0xabcdef", Hex.encode(Hex.decode("abcdef"), length = 3))
assertEquals("0xabcdef", Hex.encode(Hex.decode("abcdef"), length = 32))
assertEquals("0xaa12456789bb", Hex.encode(Hex.decode("0xaa12456789bb"), length = 6))
assertEquals("0xaa12456789bb", Hex.encode(Hex.decode("0xaa12456789bb"), length = 9))
}
@Test
fun byteArrayStartWorks() {
assertEquals("0x", Hex.encode(Hex.decode("abcdef"), start = 1, length = 1))
assertEquals("0xcd", Hex.encode(Hex.decode("abcdef"), start = 1, length = 2))
assertEquals("0xcdef", Hex.encode(Hex.decode("abcdef"), start = 1, length = 3))
assertEquals("0xcdef", Hex.encode(Hex.decode("abcdef"), start = 1, length = 32))
assertEquals("0x6789bb", Hex.encode(Hex.decode("0xaa12456789bb"), start = 3, length = 6))
assertEquals("0x456789bb", Hex.encode(Hex.decode("0xaa12456789bb"), start = 2, length = 9))
}
@Test