1 files changed, 67 insertions, 0 deletions
diff --git a/lib/compress/zstd_ldm.h b/lib/compress/zstd_ldm.h
new file mode 100644
index 000000000000..d6d3d42c337f
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+++ b/lib/compress/zstd_ldm.h
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ */
+
+#ifndef ZSTD_LDM_H
+#define ZSTD_LDM_H
+
+#include "zstd_compress.h"
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+/*-*************************************
+*  Long distance matching
+***************************************/
+
+#define ZSTD_LDM_DEFAULT_WINDOW_LOG ZSTD_WINDOWLOG_DEFAULTMAX
+#define ZSTD_LDM_HASHEVERYLOG_NOTSET 9999
+
+/** ZSTD_compressBlock_ldm_generic() :
+ *
+ *  This is a block compressor intended for long distance matching.
+ *
+ *  The function searches for matches of length at least
+ *  ldmParams.minMatchLength using a hash table in cctx->ldmState.
+ *  Matches can be at a distance of up to cParams.windowLog.
+ *
+ *  Upon finding a match, the unmatched literals are compressed using a
+ *  ZSTD_blockCompressor (depending on the strategy in the compression
+ *  parameters), which stores the matched sequences. The "long distance"
+ *  match is then stored with the remaining literals from the
+ *  ZSTD_blockCompressor. */
+size_t ZSTD_compressBlock_ldm(ZSTD_CCtx* cctx, const void* src, size_t srcSize);
+size_t ZSTD_compressBlock_ldm_extDict(ZSTD_CCtx* ctx,
+                                      const void* src, size_t srcSize);
+
+/** ZSTD_ldm_initializeParameters() :
+ *  Initialize the long distance matching parameters to their default values. */
+size_t ZSTD_ldm_initializeParameters(ldmParams_t* params, U32 enableLdm);
+
+/** ZSTD_ldm_getTableSize() :
+ *  Estimate the space needed for long distance matching tables. */
+size_t ZSTD_ldm_getTableSize(U32 hashLog, U32 bucketSizeLog);
+
+/** ZSTD_ldm_getTableSize() :
+ *  Return prime8bytes^(minMatchLength-1) */
+U64 ZSTD_ldm_getHashPower(U32 minMatchLength);
+
+/** ZSTD_ldm_adjustParameters() :
+ *  If the params->hashEveryLog is not set, set it to its default value based on
+ *  windowLog and params->hashLog.
+ *
+ *  Ensures that params->bucketSizeLog is <= params->hashLog (setting it to
+ *  params->hashLog if it is not). */
+void ZSTD_ldm_adjustParameters(ldmParams_t* params, U32 windowLog);
+
+#if defined (__cplusplus)
+}
+#endif
+
+#endif /* ZSTD_FAST_H */