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diff --git a/lib/compression/lzxpress_huffman.h b/lib/compression/lzxpress_huffman.h
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+/*
+ * Samba compression library - LGPLv3
+ *
+ * Copyright © Catalyst IT 2022
+ *
+ *  ** NOTE! The following LGPL license applies to this file.
+ *  ** It does NOT imply that all of Samba is released under the LGPL
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 3 of the License, or (at your option) any later version.
+ *
+ *  This library 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
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef HAVE_LZXPRESS_HUFFMAN_H
+#define HAVE_LZXPRESS_HUFFMAN_H
+
+
+struct huffman_node {
+	struct huffman_node *left;
+	struct huffman_node *right;
+	uint32_t count;
+	uint16_t symbol;
+	int8_t depth;
+};
+
+
+/*
+ * LZX_HUFF_COMP_HASH_BITS is how big to make the hash tables
+ * (12 means 4096, etc).
+ *
+ * A larger number (up to 16) will be faster on long messages (fewer
+ * collisions), but probably slower on short ones (more prep).
+ */
+#define LZX_HUFF_COMP_HASH_BITS 14
+
+
+/*
+ * This struct just coalesces all the memory you need for LZ77 + Huffman
+ * compression together in one bundle.
+ *
+ * There are a few different things you want, you usually want them all, so
+ * this makes it easy to allocate them all at once.
+ */
+
+struct lzxhuff_compressor_mem {
+	struct huffman_node leaf_nodes[512];
+	struct huffman_node internal_nodes[512];
+	uint16_t symbol_values[512];
+	uint16_t intermediate[65536 + 6];
+	uint16_t hash_table1[1 << LZX_HUFF_COMP_HASH_BITS];
+	uint16_t hash_table2[1 << LZX_HUFF_COMP_HASH_BITS];
+};
+
+
+ssize_t lzxpress_huffman_compress(struct lzxhuff_compressor_mem *cmp,
+				  const uint8_t *input_bytes,
+				  size_t input_size,
+				  uint8_t *output,
+				  size_t available_size);
+
+
+ssize_t lzxpress_huffman_compress_talloc(TALLOC_CTX *mem_ctx,
+					 const uint8_t *input_bytes,
+					 size_t input_size,
+					 uint8_t **output);
+
+ssize_t lzxpress_huffman_decompress(const uint8_t *input,
+				    size_t input_size,
+				    uint8_t *output,
+				    size_t max_output_size);
+
+uint8_t *lzxpress_huffman_decompress_talloc(TALLOC_CTX *mem_ctx,
+					    const uint8_t *input_bytes,
+					    size_t input_size,
+					    size_t output_size);
+
+/*
+ * lzxpress_huffman_max_compressed_size()
+ *
+ * Return the most bytes the compression can take, to allow
+ * pre-allocation.
+ */
+size_t lzxpress_huffman_max_compressed_size(size_t input_size);
+
+
+#endif /* HAVE_LZXPRESS_HUFFMAN_H */