/* insert_string.h * * Copyright 2019 The Chromium Authors * Use of this source code is governed by a BSD-style license that can be * found in the Chromium source repository LICENSE file. */ #ifndef INSERT_STRING_H #define INSERT_STRING_H #ifndef INLINE #if defined(_MSC_VER) && !defined(__clang__) #define INLINE … #else #define INLINE … #endif #endif #include <stdint.h> /** * Some applications need to match zlib DEFLATE output exactly [3]. Use the * canonical zlib Rabin-Karp rolling hash [1,2] in that case. * * [1] For a description of the Rabin and Karp algorithm, see "Algorithms" * book by R. Sedgewick, Addison-Wesley, p252. * [2] https://www.euccas.me/zlib/#zlib_rabin_karp and also "rolling hash" * https://en.wikipedia.org/wiki/Rolling_hash * [3] crbug.com/1316541 AOSP incremental client APK package OTA upgrades. */ #ifdef CHROMIUM_ZLIB_NO_CASTAGNOLI #define USE_ZLIB_RABIN_KARP_ROLLING_HASH #endif /* =========================================================================== * Update a hash value with the given input byte (Rabin-Karp rolling hash). * IN assertion: all calls to UPDATE_HASH are made with consecutive input * characters, so that a running hash key can be computed from the previous * key instead of complete recalculation each time. */ #define UPDATE_HASH(s, h, c) … /* =========================================================================== * Insert string str in the dictionary and set match_head to the previous head * of the hash chain (the most recent string with same hash key). Return * the previous length of the hash chain. * If this file is compiled with -DFASTEST, the compression level is forced * to 1, and no hash chains are maintained. * IN assertion: all calls to INSERT_STRING are made with consecutive input * characters and the first MIN_MATCH bytes of str are valid (except for * the last MIN_MATCH-1 bytes of the input file). */ local INLINE Pos insert_string(deflate_state* const s, const Pos str) { … } #endif /* INSERT_STRING_H */