Increase maximum window size

* Maximum window size in 32-bit mode is 1GB, since allocations for 2GB fail
  on my Mac.
* Maximum window size in 64-bit mode is 2GB, since that is the largest
  power of 2 that works with the overflow prevention.
* Allow `--long=windowLog` to set the window log, along with
  `--zstd=wlog=#`. These options also set the window size during
  decompression, but don't override `--memory=#` if it is set.
* Present a helpful error message when the window size is too large during
  decompression.
* The long range matcher defaults to a hash log 7 less than the window log,
  which keeps it at 20 for window log 27.
* Keep the default long range matcher window size and the default maximum
  window size at 27 for the API and CLI.
* Add tests that use the maximum window size and hash size for compression
  and decompression.

lib/compress/zstd_compress.c

@@ -429,7 +429,7 @@ size_t ZSTD_CCtxParam_setParameter(
     case ZSTD_p_enableLongDistanceMatching :
         if (value != 0) {
             ZSTD_cLevelToCCtxParams(params);
-            params->cParams.windowLog = ZSTD_LDM_WINDOW_LOG;
+            params->cParams.windowLog = ZSTD_LDM_DEFAULT_WINDOW_LOG;
         }
         return ZSTD_ldm_initializeParameters(&params->ldmParams, value);
 
@@ -1599,7 +1599,7 @@ static size_t ZSTD_compress_frameChunk (ZSTD_CCtx* cctx,
     const BYTE* ip = (const BYTE*)src;
     BYTE* const ostart = (BYTE*)dst;
     BYTE* op = ostart;
-    U32 const maxDist = 1 << cctx->appliedParams.cParams.windowLog;
+    U32 const maxDist = (U32)1 << cctx->appliedParams.cParams.windowLog;
 
     if (cctx->appliedParams.fParams.checksumFlag && srcSize)
         XXH64_update(&cctx->xxhState, src, srcSize);
@@ -1630,9 +1630,9 @@ static size_t ZSTD_compress_frameChunk (ZSTD_CCtx* cctx,
          *    windowLog <= 31 ==> 3<<29 + 1<<windowLog < 7<<29 < 1<<32.
          */
         if (cctx->lowLimit > (3U<<29)) {
-            U32 const cycleMask = (1 << ZSTD_cycleLog(cctx->appliedParams.cParams.chainLog, cctx->appliedParams.cParams.strategy)) - 1;
+            U32 const cycleMask = ((U32)1 << ZSTD_cycleLog(cctx->appliedParams.cParams.chainLog, cctx->appliedParams.cParams.strategy)) - 1;
             U32 const current = (U32)(ip - cctx->base);
-            U32 const newCurrent = (current & cycleMask) + (1 << cctx->appliedParams.cParams.windowLog);
+            U32 const newCurrent = (current & cycleMask) + ((U32)1 << cctx->appliedParams.cParams.windowLog);
             U32 const correction = current - newCurrent;
             ZSTD_STATIC_ASSERT(ZSTD_CHAINLOG_MAX <= 30);
             ZSTD_STATIC_ASSERT(ZSTD_WINDOWLOG_MAX_32 <= 30);
@@ -1688,7 +1688,7 @@ static size_t ZSTD_writeFrameHeader(void* dst, size_t dstCapacity,
     U32   const dictIDSizeCodeLength = (dictID>0) + (dictID>=256) + (dictID>=65536);   /* 0-3 */
     U32   const dictIDSizeCode = params.fParams.noDictIDFlag ? 0 : dictIDSizeCodeLength;   /* 0-3 */
     U32   const checksumFlag = params.fParams.checksumFlag>0;
-    U32   const windowSize = 1U << params.cParams.windowLog;
+    U32   const windowSize = (U32)1 << params.cParams.windowLog;
     U32   const singleSegment = params.fParams.contentSizeFlag && (windowSize >= pledgedSrcSize);
     BYTE  const windowLogByte = (BYTE)((params.cParams.windowLog - ZSTD_WINDOWLOG_ABSOLUTEMIN) << 3);
     U32   const fcsCode = params.fParams.contentSizeFlag ?
@@ -1788,7 +1788,7 @@ size_t ZSTD_getBlockSize(const ZSTD_CCtx* cctx)
 {
     ZSTD_compressionParameters const cParams =
             ZSTD_getCParamsFromCCtxParams(cctx->appliedParams, 0, 0);
-    return MIN (ZSTD_BLOCKSIZE_MAX, 1 << cParams.windowLog);
+    return MIN (ZSTD_BLOCKSIZE_MAX, (U32)1 << cParams.windowLog);
 }
 
 size_t ZSTD_compressBlock(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
@@ -1837,7 +1837,7 @@ static size_t ZSTD_loadDictionaryContent(ZSTD_CCtx* zc, const void* src, size_t
     case ZSTD_btopt:
     case ZSTD_btultra:
         if (srcSize >= HASH_READ_SIZE)
-            ZSTD_updateTree(zc, iend-HASH_READ_SIZE, iend, 1 << zc->appliedParams.cParams.searchLog, zc->appliedParams.cParams.searchLength);
+            ZSTD_updateTree(zc, iend-HASH_READ_SIZE, iend, (U32)1 << zc->appliedParams.cParams.searchLog, zc->appliedParams.cParams.searchLength);
         break;
 
     default:

lib/compress/zstd_ldm.c

@@ -14,14 +14,14 @@
 
 #define LDM_BUCKET_SIZE_LOG 3
 #define LDM_MIN_MATCH_LENGTH 64
-#define LDM_HASH_LOG 20
+#define LDM_HASH_RLOG 7
 #define LDM_HASH_CHAR_OFFSET 10
 
 size_t ZSTD_ldm_initializeParameters(ldmParams_t* params, U32 enableLdm)
 {
     ZSTD_STATIC_ASSERT(LDM_BUCKET_SIZE_LOG <= ZSTD_LDM_BUCKETSIZELOG_MAX);
     params->enableLdm = enableLdm>0;
-    params->hashLog = LDM_HASH_LOG;
+    params->hashLog = 0;
     params->bucketSizeLog = LDM_BUCKET_SIZE_LOG;
     params->minMatchLength = LDM_MIN_MATCH_LENGTH;
     params->hashEveryLog = ZSTD_LDM_HASHEVERYLOG_NOTSET;
@@ -30,6 +30,10 @@ size_t ZSTD_ldm_initializeParameters(ldmParams_t* params, U32 enableLdm)
 
 void ZSTD_ldm_adjustParameters(ldmParams_t* params, U32 windowLog)
 {
+    if (params->hashLog == 0) {
+        params->hashLog = MAX(ZSTD_HASHLOG_MIN, windowLog - LDM_HASH_RLOG);
+        assert(params->hashLog <= ZSTD_HASHLOG_MAX);
+    }
     if (params->hashEveryLog == ZSTD_LDM_HASHEVERYLOG_NOTSET) {
         params->hashEveryLog =
                 windowLog < params->hashLog ? 0 : windowLog - params->hashLog;

lib/compress/zstd_ldm.h

@@ -20,7 +20,7 @@ extern "C" {
 *  Long distance matching
 ***************************************/
 
-#define ZSTD_LDM_WINDOW_LOG 27
+#define ZSTD_LDM_DEFAULT_WINDOW_LOG ZSTD_WINDOWLOG_DEFAULTMAX
 #define ZSTD_LDM_HASHEVERYLOG_NOTSET 9999
 
 /** ZSTD_compressBlock_ldm_generic() :