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prepare java decoder for transpilation to Kotlin
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PiperOrigin-RevId: 600773230
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@eustas @copybara-github
eustas authored and copybara-github committed Jan 23, 2024
1 parent d5e697b commit 8a9cbdd
Showing 1 changed file with 32 additions and 17 deletions.
49 changes: 32 additions & 17 deletions java/org/brotli/dec/Decode.java
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Original file line number Diff line number Diff line change
Expand Up @@ -351,7 +351,7 @@ private static void decodeMetaBlockLength(State s) {
if (sizeBytes == 0) {
return;
}
for (int i = 0; i < sizeBytes; i++) {
for (int i = 0; i < sizeBytes; ++i) {
BitReader.fillBitWindow(s);
final int bits = BitReader.readFewBits(s, 8);
if (bits == 0 && i + 1 == sizeBytes && sizeBytes > 1) {
Expand All @@ -360,7 +360,7 @@ private static void decodeMetaBlockLength(State s) {
s.metaBlockLength |= bits << (i * 8);
}
} else {
for (int i = 0; i < sizeNibbles; i++) {
for (int i = 0; i < sizeNibbles; ++i) {
BitReader.fillBitWindow(s);
final int bits = BitReader.readFewBits(s, 4);
if (bits == 0 && i + 1 == sizeNibbles && sizeNibbles > 4) {
Expand Down Expand Up @@ -405,18 +405,19 @@ private static int readBlockLength(int[] tableGroup, int tableIdx, State s) {

private static void moveToFront(int[] v, int index) {
final int value = v[index];
for (; index > 0; index--) {
while (index > 0) {
v[index] = v[index - 1];
index--;
}
v[0] = value;
}

private static void inverseMoveToFrontTransform(byte[] v, int vLen) {
final int[] mtf = new int[256];
for (int i = 0; i < 256; i++) {
for (int i = 0; i < 256; ++i) {
mtf[i] = i;
}
for (int i = 0; i < vLen; i++) {
for (int i = 0; i < vLen; ++i) {
final int index = v[i] & 0xFF;
v[i] = (byte) mtf[index];
if (index != 0) {
Expand Down Expand Up @@ -470,7 +471,7 @@ private static void readHuffmanCodeLengths(
if (symbol + repeatDelta > numSymbols) {
throw new BrotliRuntimeException("symbol + repeatDelta > numSymbols"); // COV_NF_LINE
}
for (int i = 0; i < repeatDelta; i++) {
for (int i = 0; i < repeatDelta; ++i) {
codeLengths[symbol++] = repeatCodeLen;
}
if (repeatCodeLen != 0) {
Expand Down Expand Up @@ -507,7 +508,7 @@ private static int readSimpleHuffmanCode(int alphabetSizeMax, int alphabetSizeLi
final int maxBits = 1 + log2floor(alphabetSizeMax - 1);

final int numSymbols = BitReader.readFewBits(s, 2) + 1;
for (int i = 0; i < numSymbols; i++) {
for (int i = 0; i < numSymbols; ++i) {
BitReader.fillBitWindow(s);
final int symbol = BitReader.readFewBits(s, maxBits);
if (symbol >= alphabetSizeLimit) {
Expand Down Expand Up @@ -569,7 +570,7 @@ private static int readComplexHuffmanCode(int alphabetSizeLimit, int skip,
final int[] codeLengthCodeLengths = new int[CODE_LENGTH_CODES];
int space = 32;
int numCodes = 0;
for (int i = skip; i < CODE_LENGTH_CODES && space > 0; i++) {
for (int i = skip; i < CODE_LENGTH_CODES; ++i) {
final int codeLenIdx = CODE_LENGTH_CODE_ORDER[i];
BitReader.fillBitWindow(s);
final int p = BitReader.peekBits(s) & 15;
Expand All @@ -580,6 +581,7 @@ private static int readComplexHuffmanCode(int alphabetSizeLimit, int skip,
if (v != 0) {
space -= (32 >> v);
numCodes++;
if (space <= 0) break;
}
}
if (space != 0 && numCodes != 1) {
Expand Down Expand Up @@ -630,7 +632,8 @@ private static int decodeContextMap(int contextMapSize, byte[] contextMap, State
final int[] table = new int[tableSize + 1];
final int tableIdx = table.length - 1;
readHuffmanCode(alphabetSize, alphabetSize, table, tableIdx, s);
for (int i = 0; i < contextMapSize; ) {
int i = 0;
while (i < contextMapSize) {
BitReader.readMoreInput(s);
BitReader.fillBitWindow(s);
final int code = readSymbol(table, tableIdx, s);
Expand Down Expand Up @@ -829,22 +832,24 @@ private static void readMetablockHuffmanCodesAndContextMaps(State s) {
s.numDirectDistanceCodes = BitReader.readFewBits(s, 4) << s.distancePostfixBits;
// TODO(eustas): Reuse?
s.contextModes = new byte[s.numLiteralBlockTypes];
for (int i = 0; i < s.numLiteralBlockTypes;) {
int i = 0;
while (i < s.numLiteralBlockTypes) {
/* Ensure that less than 256 bits read between readMoreInput. */
final int limit = Math.min(i + 96, s.numLiteralBlockTypes);
for (; i < limit; ++i) {
while (i < limit) {
BitReader.fillBitWindow(s);
s.contextModes[i] = (byte) BitReader.readFewBits(s, 2);
i++;
}
BitReader.readMoreInput(s);
}

// TODO(eustas): Reuse?
s.contextMap = new byte[s.numLiteralBlockTypes << LITERAL_CONTEXT_BITS];
final int numLiteralTrees = decodeContextMap(s.numLiteralBlockTypes << LITERAL_CONTEXT_BITS,
s.contextMap, s);
final int contextMapLength = s.numLiteralBlockTypes << LITERAL_CONTEXT_BITS;
s.contextMap = new byte[contextMapLength];
final int numLiteralTrees = decodeContextMap(contextMapLength, s.contextMap, s);
s.trivialLiteralContext = 1;
for (int j = 0; j < s.numLiteralBlockTypes << LITERAL_CONTEXT_BITS; j++) {
for (int j = 0; j < contextMapLength; ++j) {
if (s.contextMap[j] != j >> LITERAL_CONTEXT_BITS) {
s.trivialLiteralContext = 0;
break;
Expand Down Expand Up @@ -1253,11 +1258,21 @@ static void decompress(State s) {
final int dstEnd = dst + copyLength;
if ((srcEnd < ringBufferMask) && (dstEnd < ringBufferMask)) {
if (copyLength < 12 || (srcEnd > dst && dstEnd > src)) {
for (int k = 0; k < copyLength; k += 4) {
ringBuffer[dst++] = ringBuffer[src++];
ringBuffer[dst++] = ringBuffer[src++];
ringBuffer[dst++] = ringBuffer[src++];
ringBuffer[dst++] = ringBuffer[src++];
if (copyLength > 4) {
ringBuffer[dst++] = ringBuffer[src++];
ringBuffer[dst++] = ringBuffer[src++];
ringBuffer[dst++] = ringBuffer[src++];
ringBuffer[dst++] = ringBuffer[src++];
if (copyLength > 8) {
ringBuffer[dst++] = ringBuffer[src++];
ringBuffer[dst++] = ringBuffer[src++];
ringBuffer[dst++] = ringBuffer[src++];
ringBuffer[dst++] = ringBuffer[src++];
}
}
} else {
Utils.copyBytesWithin(ringBuffer, dst, src, srcEnd);
Expand All @@ -1266,7 +1281,7 @@ static void decompress(State s) {
s.metaBlockLength -= copyLength;
s.pos += copyLength;
} else {
for (; s.j < s.copyLength;) {
while (s.j < s.copyLength) {
ringBuffer[s.pos] =
ringBuffer[(s.pos - s.distance) & ringBufferMask];
s.metaBlockLength--;
Expand Down

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