--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/lcms2/plugins/threaded/src/threaded_scheduler.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,108 @@
+//---------------------------------------------------------------------------------
+//
+//  Little Color Management System, multithreaded extensions
+//  Copyright (c) 1998-2023 Marti Maria Saguer, all rights reserved
+//
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+// 
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+//---------------------------------------------------------------------------------
+
+#include "threaded_internal.h"
+
+// The scheduler is responsible to split the work in several portions in a way that each
+// portion can be calculated by a different thread. All locking is already done by lcms 
+// mutexes, memory should not overlap.
+void  _cmsThrScheduler(struct _cmstransform_struct* CMMcargo,
+                       const void* InputBuffer,
+                       void* OutputBuffer,
+                       cmsUInt32Number PixelsPerLine,
+                       cmsUInt32Number LineCount,
+                       const cmsStride* Stride)
+{
+    cmsContext ContextID = cmsGetTransformContextID(CMMcargo);
+    _cmsTransform2Fn worker = _cmsGetTransformWorker(CMMcargo);
+    cmsInt32Number   MaxWorkers = _cmsGetTransformMaxWorkers(CMMcargo);
+
+    // flags are not actually being used
+    // cmsUInt32Number  flags = _cmsGetTransformWorkerFlags(CMMcargo);
+
+    _cmsWorkSlice master;
+    _cmsWorkSlice* slices;
+    cmsStride FixedStride = *Stride;
+    cmsHANDLE* handles;
+
+    //  Count the number of threads needed for this job. MaxWorkers is the upper limit or -1 to auto
+    cmsUInt32Number nSlices = _cmsThrCountSlices(CMMcargo, MaxWorkers, PixelsPerLine, LineCount, &FixedStride);
+    
+    // Abort early if no threaded code
+    if (nSlices <= 1) {
+
+        worker(CMMcargo, InputBuffer, OutputBuffer, PixelsPerLine, LineCount, Stride);
+        return;
+    }
+
+    // Setup master thread
+    master.CMMcargo = CMMcargo;
+    master.InputBuffer = InputBuffer;
+    master.OutputBuffer = OutputBuffer;
+    master.PixelsPerLine = PixelsPerLine;
+    master.LineCount = LineCount;
+    master.Stride = &FixedStride;
+
+    // Create memory for the slices
+    slices  = (_cmsWorkSlice*)_cmsCalloc(ContextID, nSlices, sizeof(_cmsWorkSlice));
+    handles = (cmsHANDLE*) _cmsCalloc(ContextID, nSlices, sizeof(cmsHANDLE));
+
+    if (slices == NULL || handles == NULL)
+    {
+        if (slices)  _cmsFree(ContextID, slices);
+        if (handles) _cmsFree(ContextID, handles);
+
+        // Out of memory in this case only can come from a corruption, but we do the work anyway
+        worker(CMMcargo, InputBuffer, OutputBuffer, PixelsPerLine, LineCount, Stride);
+        return;
+    }
+
+    // All seems ok so far
+    if (_cmsThrSplitWork(&master, nSlices, slices))
+    {
+        // Work is splitted. Create threads
+        cmsUInt32Number i;
+
+        for (i = 1; i < nSlices; i++)
+        {
+            handles[i] = _cmsThrCreateWorker(ContextID, worker, &slices[i]);
+        }
+
+        // Do our portion of work 
+        worker(CMMcargo, slices[0].InputBuffer, slices[0].OutputBuffer, 
+            slices[0].PixelsPerLine, slices[0].LineCount, slices[0].Stride);
+
+        // Wait until all threads are finished
+        for (i = 1; i < nSlices; i++)
+        {
+            _cmsThrJoinWorker(ContextID, handles[i]);
+        }
+    }
+    else
+    {
+        // Not able to split the work, so don't thread
+        worker(CMMcargo, InputBuffer, OutputBuffer, PixelsPerLine, LineCount, Stride);
+    }
+
+    _cmsFree(ContextID, slices);
+    _cmsFree(ContextID, handles);
+}
+