fixed 64-to-32 conversion warnings
diff --git a/programs/dibio.c b/programs/dibio.c
index 5ea384c..6e86e84 100644
--- a/programs/dibio.c
+++ b/programs/dibio.c
@@ -115,13 +115,13 @@
         unsigned long long remainingToLoad = fs64;
         U32 const nbChunks = targetChunkSize ? (U32)((fs64 + (targetChunkSize-1)) / targetChunkSize) : 1;
         U64 const chunkSize = targetChunkSize ? MIN(targetChunkSize, fs64) : fs64;
-        size_t const maxChunkSize = MIN(chunkSize, SAMPLESIZE_MAX);
+        size_t const maxChunkSize = (size_t)MIN(chunkSize, SAMPLESIZE_MAX);
         U32 cnb;
         FILE* const f = fopen(fileName, "rb");
         if (f==NULL) EXM_THROW(10, "zstd: dictBuilder: %s %s ", fileName, strerror(errno));
         DISPLAYUPDATE(2, "Loading %s...       \r", fileName);
         for (cnb=0; cnb<nbChunks; cnb++) {
-            size_t const toLoad = MIN(maxChunkSize, remainingToLoad);
+            size_t const toLoad = (size_t)MIN(maxChunkSize, remainingToLoad);
             if (toLoad > *bufferSizePtr-pos) break;
             {   size_t const readSize = fread(buff+pos, 1, toLoad, f);
                 if (readSize != toLoad) EXM_THROW(11, "Pb reading %s", fileName);
@@ -233,7 +233,7 @@
         U64 const fileSize = UTIL_getFileSize(fileNamesTable[n]);
         U32 const nbChunks = (U32)(chunkSize ? (fileSize + (chunkSize-1)) / chunkSize : 1);
         U64 const chunkToLoad = chunkSize ? MIN(chunkSize, fileSize) : fileSize;
-        size_t const cappedChunkSize = MIN(chunkToLoad, SAMPLESIZE_MAX);
+        size_t const cappedChunkSize = (size_t)MIN(chunkToLoad, SAMPLESIZE_MAX);
         fs.totalSizeToLoad += cappedChunkSize * nbChunks;
         fs.oneSampleTooLarge |= (chunkSize > 2*SAMPLESIZE_MAX);
         fs.nbChunks += nbChunks;