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Update isEarlierThan to consider NEVER
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@erlingrj
erlingrj committed Nov 22, 2023
1 parent 7689b93 commit 11d1dd9
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5 changes: 5 additions & 0 deletions core/src/main/java/org/lflang/TimeValue.java
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Original file line number Diff line number Diff line change
Expand Up @@ -114,6 +114,11 @@ private static long makeNanosecs(long time, TimeUnit unit) {

/** Returns whether this time value is earlier than another. */
public boolean isEarlierThan(TimeValue other) {
if (this == NEVER && other != NEVER) {
return true;
} else if (this != NEVER && other == NEVER) {
return false;
}
return this.compareTo(other) < 0;
}

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4 comments on commit 11d1dd9

@edwardalee
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@edwardalee edwardalee commented on 11d1dd9 Nov 22, 2023 •
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In the C runtime, NEVER is encoded as the largest negative number. In the Java code, however, we have this:

  public static final long MAX_LONG_DEADLINE = Long.decode("0x7FFFFFFFFFFF");
...
  public static final TimeValue NEVER = new TimeValue(Long.MAX_VALUE, TimeUnit.NANO);
  public static final TimeValue FOREVER = new TimeValue(MAX_LONG_DEADLINE, TimeUnit.NANO);

These look like odd definitions to me. The definition of NEVER is effectively limiting the TimeValue to 48 bits, in which case we will get overflow far sooner than the 292 years.
Anybody remember why these choices? Wouldn't it be better to encode NEVER as Long.MIN_VALUE?

@erlingrj
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Hmm. I was trying to mimic the C runtime with NEVER = 0xFFFFF..... and FOREVER=0x7FFFFFF....

@erlingrj
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Fixed it here, thanks for spotting this. I thought Long was unsigned....

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https://github.com/lf-lang/lingua-franca/pull/2104/files#diff-b84e131f3aba572980acf4d3264162097f6760c90dda64d11affc31f26337c83

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