aboutsummaryrefslogtreecommitdiff
path: root/src/liblzma/api/lzma/index_hash.h
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--src/liblzma/api/lzma/index_hash.h94
1 files changed, 94 insertions, 0 deletions
diff --git a/src/liblzma/api/lzma/index_hash.h b/src/liblzma/api/lzma/index_hash.h
new file mode 100644
index 00000000..1edbbeaa
--- /dev/null
+++ b/src/liblzma/api/lzma/index_hash.h
@@ -0,0 +1,94 @@
+/**
+ * \file lzma/index_hash.h
+ * \brief Validates Index by using a hash function
+ *
+ * Instead of constructing complete Index while decoding Blocks, Index hash
+ * calculates a hash of the Block sizes and Index, and then compares the
+ * hashes. This way memory usage is constant even with large number of
+ * Blocks and huge Index.
+ *
+ * \author Copyright (C) 2008 Lasse Collin
+ *
+ * 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 2.1 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.
+ */
+
+#ifndef LZMA_H_INTERNAL
+# error Never include this file directly. Use <lzma.h> instead.
+#endif
+
+/**
+ * \brief Opaque data type to hold the Index hash
+ */
+typedef struct lzma_index_hash_s lzma_index_hash;
+
+
+/**
+ * \brief Allocate and initialize a new lzma_index_hash structure
+ *
+ * If index_hash is NULL, a new lzma_index_hash structure is allocated,
+ * initialized, and a pointer to it returned. If allocation fails, NULL
+ * is returned.
+ *
+ * If index_hash is non-NULL, it is reinitialized and the same pointer
+ * returned. In this case, return value cannot be NULL or a different
+ * pointer than the index_hash given as argument.
+ */
+extern lzma_index_hash *lzma_index_hash_init(
+ lzma_index_hash *index_hash, lzma_allocator *allocator);
+
+
+/**
+ * \brief Deallocate the Index hash
+ */
+extern void lzma_index_hash_end(
+ lzma_index_hash *index_hash, lzma_allocator *allocator);
+
+
+/**
+ * \brief Add a new Record to an Index hash
+ *
+ * \param index Pointer to a lzma_index_hash structure
+ * \param total_size Total Size of a Block
+ * \param uncompressed_size Uncompressed Size of a Block
+ *
+ * \return - LZMA_OK
+ * - LZMA_DATA_ERROR: Compressed or uncompressed size of the
+ * Stream or size of the Index field would grow too big.
+ * - LZMA_PROG_ERROR: Invalid arguments or this function is being
+ * used when lzma_index_hash_decode() has already been used.
+ */
+extern lzma_ret lzma_index_hash_append(lzma_index_hash *index_hash,
+ lzma_vli total_size, lzma_vli uncompressed_size);
+
+
+/**
+ * \brief Decode the Index field
+ *
+ * \return - LZMA_OK: So far good, but more input is needed.
+ * - LZMA_STREAM_END: Index decoded successfully and it matches
+ * the Records given with lzma_index_hash_append().
+ * - LZMA_DATA_ERROR: Index is corrupt or doesn't match the
+ * information given with lzma_index_hash_append().
+ * - LZMA_PROG_ERROR
+ *
+ * \note Once decoding of the Index field has been started, no more
+ * Records can be added using lzma_index_hash_append().
+ */
+extern lzma_ret lzma_index_hash_decode(lzma_index_hash *index_hash,
+ const uint8_t *in, size_t *in_pos, size_t in_size);
+
+
+/**
+ * \brief Get the size of the Index field as bytes
+ *
+ * This is needed to verify the Index Size field from the Stream Footer.
+ */
+extern lzma_vli lzma_index_hash_size(const lzma_index_hash *index_hash);