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Merged
05nelsonm merged 2 commits into from
Dec 14, 2025
Merged

Use Int and Long, instead of arrays, when buffering input #236

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a704ea7
Buffer input using Long instead of an array
05nelsonm Dec 14, 2025
599e08b
Buffer input using Int instead of an array
05nelsonm Dec 14, 2025
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138 changes: 47 additions & 91 deletions library/base32/src/commonMain/kotlin/io/matthewnelson/encoding/base32/Base32.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -1140,8 +1140,8 @@ public sealed class Base32<C: EncoderDecoder.Config>(config: C): EncoderDecoder<

protected abstract fun Int.decodeDiff(): Int

private val buf = IntArray(7)
private var iBuf = 0
private var _count = 0
private var _word = 0L

override fun consumeProtected(input: Char) {
val code = input.code
Expand All @@ -1150,21 +1150,15 @@ public sealed class Base32<C: EncoderDecoder.Config>(config: C): EncoderDecoder<
throw MalformedEncodingException("Char[$input] is not a valid ${name()} character")
}

if (iBuf < 7) {
buf[iBuf++] = code + diff
// Append each character's 5 bits to the word
val word = _word shl 5 or (code + diff).toLong()

if (_count++ < 7) {
_word = word
return // Await more input
}

// Append each character's 5 bits to the word
var word: Long = buf[0].toLong()
word = word shl 5 or buf[1].toLong()
word = word shl 5 or buf[2].toLong()
word = word shl 5 or buf[3].toLong()
word = word shl 5 or buf[4].toLong()
word = word shl 5 or buf[5].toLong()
word = word shl 5 or buf[6].toLong()
word = word shl 5 or (code + diff).toLong()
iBuf = 0
_count = 0
_word = 0L

// For every 8 characters of input, 40 bits of output are accumulated. Emit 5 bytes.
_out.output((word shr 32).toByte())
Expand All @@ -1175,47 +1169,29 @@ public sealed class Base32<C: EncoderDecoder.Config>(config: C): EncoderDecoder<
}

override fun doFinalProtected() {
if (iBuf == 0) return buf.fill(0)
val count = _count
if (count == 0) return
var word = _word
_count = 0
_word = 0L

if (iBuf == 1) {
if (count == 1) {
// 5*1 = 5 bits. Truncated, fail.
iBuf = 0
buf.fill(0)
throw FeedBuffer.truncatedInputEncodingException(1)
}
if (iBuf == 3) {
// 5*3 = 15 bits. Truncated, fail.
iBuf = 0
buf.fill(0)
throw FeedBuffer.truncatedInputEncodingException(3)
}
if (iBuf == 6) {
// 5*6 = 30 bits. Truncated, fail.
iBuf = 0
buf.fill(0)
throw FeedBuffer.truncatedInputEncodingException(6)
}

// iBuf == 2, 4, 5 or 7
// Append each character's 5 bits to the word
var word: Long = buf[0].toLong()
word = word shl 5 or buf[1].toLong()
if (iBuf == 2) {
iBuf = 0
buf.fill(0)
if (count == 2) {
// 5*2 = 10 bits. Drop 2
word = word shr 2

// 8/8 = 1 byte
_out.output((word ).toByte())
return
}

word = word shl 5 or buf[2].toLong()
word = word shl 5 or buf[3].toLong()
if (iBuf == 4) {
iBuf = 0
buf.fill(0)
if (count == 3) {
// 5*3 = 15 bits. Truncated, fail.
throw FeedBuffer.truncatedInputEncodingException(3)
}
if (count == 4) {
// 5*4 = 20 bits. Drop 4
word = word shr 4

Expand All @@ -1224,11 +1200,7 @@ public sealed class Base32<C: EncoderDecoder.Config>(config: C): EncoderDecoder<
_out.output((word ).toByte())
return
}

word = word shl 5 or buf[4].toLong()
if (iBuf == 5) {
iBuf = 0
buf.fill(0)
if (count == 5) {
// 5*5 = 25 bits. Drop 1
word = word shr 1

Expand All @@ -1238,12 +1210,11 @@ public sealed class Base32<C: EncoderDecoder.Config>(config: C): EncoderDecoder<
_out.output((word ).toByte())
return
}

word = word shl 5 or buf[5].toLong()
word = word shl 5 or buf[6].toLong()
if (iBuf == 7) {
iBuf = 0
buf.fill(0)
if (count == 6) {
// 5*6 = 30 bits. Truncated, fail.
throw FeedBuffer.truncatedInputEncodingException(6)
}
if (count == 7) {
// 5*7 = 35 bits. Drop 3
word = word shr 3

Expand All @@ -1256,7 +1227,7 @@ public sealed class Base32<C: EncoderDecoder.Config>(config: C): EncoderDecoder<
}

// "Should" never make it here
error("Illegal configuration >> iBuf[$iBuf] - buf[${buf[0]}, ${buf[1]}, ${buf[2]}, ${buf[3]}, ${buf[4]}, ${buf[5]}, ${buf[6]}]")
error("Illegal configuration >> count[$count]")
}
}

Expand All @@ -1265,22 +1236,19 @@ public sealed class Base32<C: EncoderDecoder.Config>(config: C): EncoderDecoder<
protected abstract fun Encoder.OutFeed.output1(i: Int)
protected abstract fun Encoder.OutFeed.outputPadding(n: Int)

private val buf = ByteArray(4)
private var iBuf = 0
private var _count = 0
private var _word = 0L

final override fun consumeProtected(input: Byte) {
if (iBuf < 4) {
buf[iBuf++] = input
// Append each character's 8 bits to the word
val word = (_word shl 8) + input.toBits()

if (_count++ < 4) {
_word = word
return // Await more input
}

// Append each character's 8 bits to the word
var word: Long = buf[0].toBits()
word = (word shl 8) + buf[1].toBits()
word = (word shl 8) + buf[2].toBits()
word = (word shl 8) + buf[3].toBits()
word = (word shl 8) + input.toBits()
iBuf = 0
_count = 0
_word = 0L

// For every 5 bytes of input, 40 bits of output are accumulated. Emit 8 characters.
_out.output1(i = (word shr 35 and 0x1fL).toInt()) // 40-1*5 = 35
Expand All @@ -1294,38 +1262,30 @@ public sealed class Base32<C: EncoderDecoder.Config>(config: C): EncoderDecoder<
}

final override fun doFinalProtected() {
if (iBuf == 0) {
buf.fill(0)
val count = _count
if (count == 0) {
// Still call with 0 b/c Crockford uses to append its check symbol
return _out.outputPadding(n = 0)
}
val word = _word
_count = 0
_word = 0L

var word: Long = buf[0].toBits()
if (iBuf == 1) {
iBuf = 0
buf.fill(0)
if (count == 1) {
// 8*1 = 8 bits
_out.output1(i = (word shr 3 and 0x1fL).toInt()) // 8-1*5 = 3
_out.output1(i = (word shl 2 and 0x1fL).toInt()) // 5-3 = 2
return _out.outputPadding(n = 6)
}

word = (word shl 8) + buf[1].toBits()
if (iBuf == 2) {
iBuf = 0
buf.fill(0)
if (count == 2) {
// 8*2 = 16 bits
_out.output1(i = (word shr 11 and 0x1fL).toInt()) // 16-1*5 = 11
_out.output1(i = (word shr 6 and 0x1fL).toInt()) // 16-2*5 = 6
_out.output1(i = (word shr 1 and 0x1fL).toInt()) // 16-3*5 = 1
_out.output1(i = (word shl 4 and 0x1fL).toInt()) // 5-1 = 4
return _out.outputPadding(n = 4)
}

word = (word shl 8) + buf[2].toBits()
if (iBuf == 3) {
iBuf = 0
buf.fill(0)
if (count == 3) {
// 8*3 = 24 bits
_out.output1(i = (word shr 19 and 0x1fL).toInt()) // 24-1*5 = 19
_out.output1(i = (word shr 14 and 0x1fL).toInt()) // 24-2*5 = 14
Expand All @@ -1334,11 +1294,7 @@ public sealed class Base32<C: EncoderDecoder.Config>(config: C): EncoderDecoder<
_out.output1(i = (word shl 1 and 0x1fL).toInt()) // 5-4 = 1
return _out.outputPadding(n = 3)
}

word = (word shl 8) + buf[3].toBits()
if (iBuf == 4) {
iBuf = 0
buf.fill(0)
if (count == 4) {
// 8*4 = 32 bits
_out.output1(i = (word shr 27 and 0x1fL).toInt()) // 32-1*5 = 27
_out.output1(i = (word shr 22 and 0x1fL).toInt()) // 32-2*5 = 22
Expand All @@ -1351,7 +1307,7 @@ public sealed class Base32<C: EncoderDecoder.Config>(config: C): EncoderDecoder<
}

// "Should" never make it here
error("Illegal configuration >> iBuf[$iBuf] - buf[${buf[0]}, ${buf[1]}, ${buf[2]}, ${buf[3]}]")
error("Illegal configuration >> count[$count]")
}

private inline fun Byte.toBits(): Long = if (this < 0) this + 256L else toLong()
Expand Down
47 changes: 18 additions & 29 deletions library/base64/src/commonMain/kotlin/io/matthewnelson/encoding/base64/Base64.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -417,8 +417,8 @@ public class Base64: EncoderDecoder<Base64.Config> {

private inner class DecoderFeed(out: Decoder.OutFeed): Decoder<Config>.Feed(_out = out) {

private val buf = IntArray(3)
private var iBuf = 0
private var _count = 0
private var _word = 0

override fun consumeProtected(input: Char) {
val code = input.code
Expand Down Expand Up @@ -460,17 +460,15 @@ public class Base64: EncoderDecoder<Base64.Config> {
throw MalformedEncodingException("Char[$input] is not a valid $NAME character")
}

if (iBuf < 3) {
buf[iBuf++] = code + diff
// Append each character's 6 bits to the word
val word = _word shl 6 or (code + diff)

if (_count++ < 3) {
_word = word
return // Await more input
}

// Append each character's 6 bits to the word
var word = buf[0]
word = word shl 6 or buf[1]
word = word shl 6 or buf[2]
word = word shl 6 or (code + diff)
iBuf = 0
_count = 0
_word = 0

// For every 4 characters of input, 24 bits of output are accumulated. Emit 3 bytes.
_out.output((word shr 16).toByte())
Expand All @@ -479,32 +477,23 @@ public class Base64: EncoderDecoder<Base64.Config> {
}

override fun doFinalProtected() {
if (iBuf == 0) return buf.fill(0)
val count = _count
if (count == 0) return
var word = _word
_count = 0
_word = 0

if (iBuf == 1) {
iBuf = 0
buf.fill(0)
if (count == 1) {
// 1 character followed by "===". But 6 bits is a truncated byte, fail.
throw FeedBuffer.truncatedInputEncodingException(1)
}

// Append each character's 6 bits to the word
var word = buf[0]
word = word shl 6 or buf[1]

if (iBuf == 2) {
iBuf = 0
buf.fill(0)
if (count == 2) {
// 2 characters followed by "==". Emit 1 byte for 8 of those 12 bits.
word = word shl 12
_out.output((word shr 16).toByte())
return
}

word = word shl 6 or buf[2]
if (iBuf == 3) {
iBuf = 0
buf.fill(0)
if (count == 3) {
// 3 characters followed by "=". Emit 2 byte for 16 of those 18 bits.
word = word shl 6
_out.output((word shr 16).toByte())
Expand All @@ -513,7 +502,7 @@ public class Base64: EncoderDecoder<Base64.Config> {
}

// "Should" never make it here
error("Illegal configuration >> iBuf[$iBuf] - buf[${buf[0]}, ${buf[1]}, ${buf[2]}]")
error("Illegal configuration >> count[$count]")
}
}

Expand Down