Avoid passing 64-bit ints through LibraryLink (#648)

## Changes

* Closes #641.
* We are currently passing 64-bit ints for disabled step specs, and an unsigned 32-bit for the seed initialization. WL LibraryLink does not support that on 32-bit platforms, so any calls to `libSetReplace` would fail.
* This PR changes it to pass -1 and 31-bit ints instead, which should fix that issue.

## Comments

* Someone with a 32-bit system needs to confirm there is nothing else here I'm missing.

Author: maxitg

Kernel/setSubstitutionSystem$cpp.m

@@ -13,7 +13,8 @@
    Integer,                  (* event selection function *)
    {Integer, 1, "Constant"}, (* ordering function index, forward / reverse, function, forward / reverse, ... *)
    Integer,                  (* event deduplication *)
-   Integer},                 (* random seed *)
+   (* random seed, passed as two numbers because LibraryLink does not support unsigned ints *)
+   {Integer, 1, "Constant"}},
   "Void"];
 
 importLibSetReplaceFunction[
@@ -102,7 +103,7 @@
   newLeft -> newRight
 ];
 
-$maxInt64 = 2^63 - 1;
+$unset = -1;
 $maxUInt32 = 2^32 - 1;
 
 $terminationReasonCodes = <|
@@ -119,7 +120,7 @@
 (* GlobalSpacelike is syntactic sugar for "EventSelectionFunction" -> "MultiwaySpacelike", "MaxDestroyerEvents" -> 1 *)
 
 maxDestroyerEvents[_, $globalSpacelike] = 1;
-maxDestroyerEvents[Automatic | _ ? MissingQ | Infinity, _] = $maxInt64;
+maxDestroyerEvents[Automatic | _ ? MissingQ | Infinity, _] = $unset;
 maxDestroyerEvents[n_, _] := n;
 
 (* 0 -> All
@@ -171,15 +172,15 @@
     maxDestroyerEvents[stepSpec[$maxDestroyerEvents], eventSelectionFunction],
     Catenate[Replace[eventOrderingFunction, $orderingFunctionCodes, {2}]],
     Replace[eventDeduplication, $eventDeduplicationCodes],
-    RandomInteger[{0, $maxUInt32}]
+    IntegerDigits[RandomInteger[{0, $maxUInt32}], 2^16, 2]
   ];
   TimeConstrained[
     CheckAbort[
       cpp$setReplace[
         setID,
         stepSpec /@ {
             $maxEvents, $maxGenerationsLocal, $maxFinalVertices, $maxFinalVertexDegree, $maxFinalExpressions} /.
-          {Infinity | (_ ? MissingQ) -> $maxInt64}],
+          {Infinity | (_ ? MissingQ) -> $unset}],
       If[!returnOnAbortQ, Abort[], terminationReason = $Aborted]],
     timeConstraint,
     If[!returnOnAbortQ, Return[$Aborted], terminationReason = $timeConstraint]];

libSetReplace/WolframLanguageAPI.cpp

@@ -105,6 +105,21 @@ HypergraphMatcher::OrderingSpec getOrderingSpec(WolframLibraryData libData, MTen
   return result;
 }
 
+// Seed is passed as two uint16_t because LibraryLink does not support unsigned ints, which becomes a problem on 32-bit
+// architectures
+uint32_t getSeed(WolframLibraryData libData, MTensor seedTensor) {
+  mint tensorLength = libData->MTensor_getFlattenedLength(seedTensor);
+  if (tensorLength != 2) throw LIBRARY_FUNCTION_ERROR;
+  mint* tensorData = libData->MTensor_getIntegerData(seedTensor);
+  uint32_t result = 0;
+  for (mint i = 0; i < tensorLength; ++i) {
+    result = (1 << 16) * result + static_cast<uint32_t>(getData(tensorData, tensorLength, i));
+  }
+  return result;
+}
+
+constexpr int64_t wlStepLimitDisabled = -1;
+
 HypergraphSubstitutionSystem::StepSpecification getStepSpec(WolframLibraryData libData, MTensor stepsTensor) {
   mint tensorLength = libData->MTensor_getFlattenedLength(stepsTensor);
   constexpr mint specLength = 5;
@@ -115,6 +130,9 @@ HypergraphSubstitutionSystem::StepSpecification getStepSpec(WolframLibraryData l
     std::vector<int64_t> stepSpecElements(specLength);
     for (mint k = 0; k < specLength; ++k) {
       stepSpecElements[k] = static_cast<int64_t>(getData(tensorData, specLength, k));
+      if (stepSpecElements[k] == wlStepLimitDisabled) {
+        stepSpecElements[k] = HypergraphSubstitutionSystem::stepLimitDisabled;
+      }
       if (stepSpecElements[k] < 0) throw LIBRARY_FUNCTION_ERROR;
     }
 
@@ -230,6 +248,9 @@ int hypergraphSubstitutionSystemInitialize(WolframLibraryData libData,
   SystemID thisSystemID;
   std::vector<Rule> rules;
   std::vector<AtomsVector> initialTokens;
+  // WL passes wlStepLimitDisabled (-1) instead of HypergraphSubstitutionSystem::stepLimitDisabled (max int64) for
+  // infinity because passing 64-bit ints is not supported on 32-bit systems in LibraryLink
+  int64_t wlMaxDestroyerEvents;
   uint64_t maxDestroyerEvents;
   HypergraphMatcher::OrderingSpec orderingSpec;
   HypergraphMatcher::EventDeduplication eventDeduplication;
@@ -238,10 +259,12 @@ int hypergraphSubstitutionSystemInitialize(WolframLibraryData libData,
     thisSystemID = MArgument_getInteger(argv[0]);
     rules = getRules(libData, MArgument_getMTensor(argv[1]), MArgument_getMTensor(argv[2]));
     initialTokens = getHypergraph(libData, MArgument_getMTensor(argv[3]));
-    maxDestroyerEvents = MArgument_getInteger(argv[4]);
+    wlMaxDestroyerEvents = MArgument_getInteger(argv[4]);
+    maxDestroyerEvents = wlMaxDestroyerEvents == wlStepLimitDisabled ? HypergraphSubstitutionSystem::stepLimitDisabled
+                                                                     : wlMaxDestroyerEvents;
     orderingSpec = getOrderingSpec(libData, MArgument_getMTensor(argv[5]));
     eventDeduplication = static_cast<HypergraphMatcher::EventDeduplication>(MArgument_getInteger(argv[6]));
-    randomSeed = static_cast<unsigned int>(MArgument_getInteger(argv[7]));
+    randomSeed = getSeed(libData, MArgument_getMTensor(argv[7]));
   } catch (...) {
     return LIBRARY_FUNCTION_ERROR;
   }