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fix #30 #254

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fix #30 #254

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a88b8a6
fix #30
demon36 Jul 6, 2021
3fb7cec
implement WStringRef (mapping for wchar_t*), make set() work efficien…
demon36 Aug 6, 2021
b4ab181
bug fix for null terminated strings of allocated size less than maxLe…
demon36 Aug 12, 2021
d1658b9
utf-16/32 support for getCharSequence()
demon36 Aug 12, 2021
61ce834
revert unneeded length change, add WStringRef.reAllocate() & setMaxLe…
demon36 Aug 13, 2021
9d1d562
possible fixes for DirectMemoryIO.getString()
demon36 Aug 13, 2021
b796974
more compliant spacing
demon36 Aug 17, 2021
badc99e
make use of StringUtil.terminatorWidth() for better performance
demon36 Aug 18, 2021
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27 changes: 25 additions & 2 deletions src/main/java/jnr/ffi/provider/jffi/DirectMemoryIO.java
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@

import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;

class DirectMemoryIO extends AbstractMemoryIO {
static final com.kenai.jffi.MemoryIO IO = com.kenai.jffi.MemoryIO.getInstance();
Expand Down Expand Up @@ -186,8 +187,30 @@ public String getString(long offset) {


public String getString(long offset, int maxLength, Charset cs) {
final byte[] bytes = IO.getZeroTerminatedByteArray(address() + offset, maxLength);
return cs.decode(ByteBuffer.wrap(bytes)).toString();
if(cs == StandardCharsets.UTF_8){
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Please reformat according to more common Java formatting standards:

if (cond) {
...
} else {
...
for (stuff) {
...

Otherwise we get a mix of formats and future patches will likely include unhelpful formatting updates.

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I think this logic could apply to any Charset that has a minimum character width of 1 byte, correct? All such encodings should use a single-byte \0 for C string termination I think?

At the very least this should include the ISO-8859 encodings, which are all single-byte (their CharsetEncoder.maxBytesPerChar will all be 1.0).

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agree that I should include other single byte terminator charsets, but CharsetEncoder.maxBytesPerChar won't be sufficient because it does not resolve to 1.0 for utf-8

final byte[] bytes = IO.getZeroTerminatedByteArray(address() + offset, maxLength);
return cs.decode(ByteBuffer.wrap(bytes)).toString();
}else{
byte[] bytes = new byte[maxLength];
IO.getByteArray(address() + offset, bytes, 0, maxLength);
final byte[] nullCharBytes = new String("\0").getBytes(cs);
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This could possibly be cached for common encodings (UTF-16, UTF-32) or it might be valid to just use a width of \0 equal to the encoding's CharsetEncoder.maxBytesPerChar value.

int nullIndex = maxLength;
int matchingBytesCount = 0;
for(int i = 0; i < (int)bytes.length; i++){
if(bytes[i] == nullCharBytes[matchingBytesCount]){
matchingBytesCount++;
} else {
matchingBytesCount = 0;
}

if(matchingBytesCount == nullCharBytes.length){
nullIndex = i;
break;
}
}

return new String(bytes, 0, nullIndex, cs);
}
}

public void putString(long offset, String string, int maxLength, Charset cs) {
Expand Down