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[cbor] Write large numbers in uint32 form where possible #200

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[cbor] Write large numbers in uint32 form where possible #200

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91 changes: 22 additions & 69 deletions cbor/src/main/java/com/fasterxml/jackson/dataformat/cbor/CBORGenerator.java
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Expand Up @@ -114,9 +114,6 @@ public int getMask() {
*/
private final static int MIN_BUFFER_LENGTH = (3 * 256) + 2;

private final static long MIN_INT_AS_LONG = (long) Integer.MIN_VALUE;
private final static long MAX_INT_AS_LONG = (long) Integer.MAX_VALUE;

/**
* Special value that is use to keep tracks of arrays and maps opened with infinite length
*/
Expand Down Expand Up @@ -630,9 +627,20 @@ private final void _pushRemainingElements() {
}

private final void _writeNumberNoCheck(int i) throws IOException {
int marker;
if (i < 0) {
i = -i - 1;
_writeNumberNoCheck(true, -i - 1);
} else {
_writeNumberNoCheck(false, i);
}
}

/**
* Write {@code signum ? -i - 1 : i}. This allows writing numbers that are outside the range of java {@code int}
* but still can be encoded as 4 bytes + 1 marker byte.
*/
private final void _writeNumberNoCheck(boolean signum, int i) throws IOException {
int marker;
if (signum) {
marker = PREFIX_TYPE_INT_NEG;
} else {
marker = PREFIX_TYPE_INT_POS;
Expand All @@ -642,7 +650,7 @@ private final void _writeNumberNoCheck(int i) throws IOException {
_ensureRoomForOutput(5);

byte b0;
if (_cfgMinimalInts) {
if (_cfgMinimalInts && i >= 0) {
if (i < 24) {
_outputBuffer[_outputTail++] = (byte) (marker + i);
return;
Expand Down Expand Up @@ -673,8 +681,12 @@ private final void _writeNumberNoCheck(int i) throws IOException {

private final void _writeNumberNoCheck(long l) throws IOException {
if (_cfgMinimalInts) {
if (l <= MAX_INT_AS_LONG && l >= MIN_INT_AS_LONG) {
_writeNumberNoCheck((int) l);
if (l >= 0 && l < 0x100000000L) {
_writeNumberNoCheck(false, (int) l);
return;
}
if (l < 0 && l >= -0x100000000L) {
_writeNumberNoCheck(true, (int) (-l - 1));
return;
}
}
Expand Down Expand Up @@ -895,72 +907,13 @@ public void writeNull() throws IOException {
@Override
public void writeNumber(int i) throws IOException {
_verifyValueWrite("write number");
int marker;
if (i < 0) {
i = -i - 1;
marker = PREFIX_TYPE_INT_NEG;
} else {
marker = PREFIX_TYPE_INT_POS;
}
_ensureRoomForOutput(5);
byte b0;
if (_cfgMinimalInts) {
if (i < 24) {
_outputBuffer[_outputTail++] = (byte) (marker + i);
return;
}
if (i <= 0xFF) {
_outputBuffer[_outputTail++] = (byte) (marker + SUFFIX_UINT8_ELEMENTS);
_outputBuffer[_outputTail++] = (byte) i;
return;
}
b0 = (byte) i;
i >>= 8;
if (i <= 0xFF) {
_outputBuffer[_outputTail++] = (byte) (marker + SUFFIX_UINT16_ELEMENTS);
_outputBuffer[_outputTail++] = (byte) i;
_outputBuffer[_outputTail++] = b0;
return;
}
} else {
b0 = (byte) i;
i >>= 8;
}
_outputBuffer[_outputTail++] = (byte) (marker + SUFFIX_UINT32_ELEMENTS);
_outputBuffer[_outputTail++] = (byte) (i >> 16);
_outputBuffer[_outputTail++] = (byte) (i >> 8);
_outputBuffer[_outputTail++] = (byte) i;
_outputBuffer[_outputTail++] = b0;
_writeNumberNoCheck(i);
}

@Override
public void writeNumber(long l) throws IOException {
if (_cfgMinimalInts) {
// First: maybe 32 bits is enough?
if (l <= MAX_INT_AS_LONG && l >= MIN_INT_AS_LONG) {
writeNumber((int) l);
return;
}
}
_verifyValueWrite("write number");
_ensureRoomForOutput(9);
if (l < 0L) {
l += 1;
l = -l;
_outputBuffer[_outputTail++] = (PREFIX_TYPE_INT_NEG + SUFFIX_UINT64_ELEMENTS);
} else {
_outputBuffer[_outputTail++] = (PREFIX_TYPE_INT_POS + SUFFIX_UINT64_ELEMENTS);
}
int i = (int) (l >> 32);
_outputBuffer[_outputTail++] = (byte) (i >> 24);
_outputBuffer[_outputTail++] = (byte) (i >> 16);
_outputBuffer[_outputTail++] = (byte) (i >> 8);
_outputBuffer[_outputTail++] = (byte) i;
i = (int) l;
_outputBuffer[_outputTail++] = (byte) (i >> 24);
_outputBuffer[_outputTail++] = (byte) (i >> 16);
_outputBuffer[_outputTail++] = (byte) (i >> 8);
_outputBuffer[_outputTail++] = (byte) i;
_writeNumberNoCheck(l);
}

@Override
Expand Down
20 changes: 18 additions & 2 deletions cbor/src/test/java/com/fasterxml/jackson/dataformat/cbor/gen/GeneratorSimpleTest.java
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Expand Up @@ -71,19 +71,35 @@ public void testMinimalIntValues() throws Exception

out = new ByteArrayOutputStream();
gen = cborGenerator(out);
gen.writeNumber(Integer.MAX_VALUE);
gen.writeNumber((long) Integer.MAX_VALUE);
gen.close();
_verifyBytes(out.toByteArray(),
(byte) (CBORConstants.PREFIX_TYPE_INT_POS + 26),
(byte) 0x7F, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF);

out = new ByteArrayOutputStream();
gen = cborGenerator(out);
gen.writeNumber(Integer.MIN_VALUE);
gen.writeNumber((long) Integer.MIN_VALUE);
gen.close();
_verifyBytes(out.toByteArray(),
(byte) (CBORConstants.PREFIX_TYPE_INT_NEG + 26),
(byte) 0x7F, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF);

out = new ByteArrayOutputStream();
gen = cborGenerator(out);
gen.writeNumber(0xffffffffL);
gen.close();
_verifyBytes(out.toByteArray(),
(byte) (CBORConstants.PREFIX_TYPE_INT_POS + 26),
(byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF);

out = new ByteArrayOutputStream();
gen = cborGenerator(out);
gen.writeNumber(-0xffffffffL - 1);
gen.close();
_verifyBytes(out.toByteArray(),
(byte) (CBORConstants.PREFIX_TYPE_INT_NEG + 26),
(byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF);
}

public void testIntValues() throws Exception
Expand Down