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Diffstat (limited to 'indra/llmessage/tests/llzerocode_test.cpp')
| -rw-r--r-- | indra/llmessage/tests/llzerocode_test.cpp | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/indra/llmessage/tests/llzerocode_test.cpp b/indra/llmessage/tests/llzerocode_test.cpp new file mode 100644 index 0000000000..1aba46149d --- /dev/null +++ b/indra/llmessage/tests/llzerocode_test.cpp @@ -0,0 +1,253 @@ +/** + * @file llzerocode_test.cpp + * @brief LLZeroCode test cases. + * + * $LicenseInfo:firstyear=2026&license=viewerlgpl$ + * Second Life Viewer Source Code + * Copyright (C) 2010, Linden Research, Inc. + * + * 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; + * version 2.1 of the License only. + * + * 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, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * + * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA + * $/LicenseInfo$ + */ + +#include "linden_common.h" + +#include "../llzerocode.h" + +#include "../test/lltut.h" + +#include <vector> + +namespace tut +{ + struct zerocode_data + { + }; + typedef test_group<zerocode_data> zerocode_test; + typedef zerocode_test::object zerocode_object; + tut::zerocode_test zerocode_testcase("LLZeroCode"); + + // Builds header_size bytes of header (with header[0] == header0) followed by body. + static std::vector<U8> makeBuffer(U32 header_size, U8 header0, const std::vector<U8>& body) + { + std::vector<U8> buf(header_size, 0); + if (header_size) + { + buf[0] = header0; + } + buf.insert(buf.end(), body.begin(), body.end()); + return buf; + } + + // Runs src through encode() then decode(), and (when compression is expected to help) + // asserts the round trip reproduces src exactly, including untouched header bits other + // than the zero-code flag. When compression is not expected to help, asserts encode() + // refuses it. + static void ensureRoundTrip(const char* msg, U32 header_size, U8 header0, + const std::vector<U8>& body, bool expect_compressed) + { + std::vector<U8> src = makeBuffer(header_size, header0, body); + std::vector<U8> enc(2 * src.size() + 16, 0xAA); + + S32 enc_size = LLZeroCode::encode(src.data(), (U32)src.size(), + enc.data(), (U32)enc.size(), header_size); + + if (!expect_compressed) + { + ensure(std::string(msg) + ": encode should refuse (no benefit)", enc_size < 0); + return; + } + + ensure(std::string(msg) + ": encode should succeed", enc_size >= 0); + ensure(std::string(msg) + ": encoded size should be smaller", (U32)enc_size < src.size()); + ensure(std::string(msg) + ": FLAG should be set on encoded output", (enc[0] & LLZeroCode::FLAG) != 0); + if (header_size > 0) + { + ensure_equals(std::string(msg) + ": non-flag header bits preserved on encode", + (U8)(enc[0] & ~LLZeroCode::FLAG), (U8)(header0 & ~LLZeroCode::FLAG)); + } + + std::vector<U8> dec(src.size() + 16, 0xBB); + bool overflow = false; + U32 dec_size = LLZeroCode::decode(enc.data(), (U32)enc_size, + dec.data(), (U32)dec.size(), header_size, overflow); + ensure(std::string(msg) + ": decode should not overflow", !overflow); + ensure_equals(std::string(msg) + ": decoded size should match original", dec_size, (U32)src.size()); + ensure(std::string(msg) + ": decoded bytes should match original", + memcmp(dec.data(), src.data(), src.size()) == 0); + } + + // Basic mixed body; header carries an unrelated flag bit (0x40) that must survive untouched. + template<> template<> + void zerocode_object::test<1>() + { + ensureRoundTrip("mixed body", 6, 0x40, + {0,0,0,5,0,0,0,0,0,0,7,8,9,0,0}, true); + } + + // A body with no zero bytes at all cannot benefit from zero-coding. + template<> template<> + void zerocode_object::test<2>() + { + ensureRoundTrip("no zero bytes", 1, 0x00, {1,2,3,4,5,6,7,8,9}, false); + } + + // Isolated zero-byte runs of length 1 or 2 cost as much or more than they save + // (marker + terminator == 2 bytes), so encode must refuse them. + template<> template<> + void zerocode_object::test<3>() + { + ensureRoundTrip("isolated single zero", 1, 0x00, {5, 0}, false); + ensureRoundTrip("isolated double zero", 1, 0x00, {5, 0, 0, 9}, false); + } + + // A long enough zero run followed by other data pays off. + template<> template<> + void zerocode_object::test<4>() + { + std::vector<U8> body(20, 0); + body.push_back(99); + ensureRoundTrip("long zero run", 1, 0x00, body, true); + } + + // Wrap boundary: runs are split into chunks of at most 255 zero bytes each + // (encode never emits the doubled-0x00 wire form; see test<7> for that). + // A run only shrinks the packet once it is longer than 2 bytes. + template<> template<> + void zerocode_object::test<5>() + { + static const U32 lengths[] = {1, 2, 253, 254, 255, 256, 257, 300, 509, 510, 511, 1000}; + for (U32 n : lengths) + { + std::vector<U8> body(n, 0); + body.push_back(42); // trailing nonzero byte + ensureRoundTrip("wrap boundary (with trailing byte)", 1, 0x00, body, n > 2); + } + } + + // Same boundary check, but with the zero run flushed at end-of-buffer + // (no trailing nonzero byte to force the terminator write mid-loop). + template<> template<> + void zerocode_object::test<6>() + { + static const U32 lengths[] = {1, 2, 254, 255, 256, 300}; + for (U32 n : lengths) + { + std::vector<U8> body(n, 0); + ensureRoundTrip("wrap boundary (end-of-buffer flush)", 1, 0x00, body, n > 2); + } + } + + // decode() must also accept the "0x00 0x00 N" doubled-marker wire format + // (worth +255 zero bytes per extra marker) for compatibility with any + // encoder other than this one's chunking strategy, even though encode() + // itself never emits it. + template<> template<> + void zerocode_object::test<7>() + { + // header (1 byte, FLAG set) + [0x00 marker][0x00 extra-wrap-marker][terminator=5] + // decoded body length = 1 (marker) + 1 (extra marker) + 255 (memset) + (5 - 1) = 261 + std::vector<U8> encoded = {(U8)LLZeroCode::FLAG, 0x00, 0x00, 0x05}; + std::vector<U8> dec(1024, 0xDD); + bool overflow = false; + U32 dec_size = LLZeroCode::decode(encoded.data(), (U32)encoded.size(), + dec.data(), (U32)dec.size(), 1, overflow); + ensure("wrap format: no overflow", !overflow); + ensure_equals("wrap format: decoded size", dec_size, (U32)262); + ensure_equals("wrap format: FLAG cleared on header", dec[0], (U8)0x00); + for (U32 i = 1; i < dec_size; ++i) + { + ensure_equals("wrap format: decoded byte is zero", dec[i], (U8)0); + } + } + + // decode() is a no-op (returns 0, does not touch dst) when FLAG is not set. + template<> template<> + void zerocode_object::test<8>() + { + std::vector<U8> src = makeBuffer(6, 0x00, {1,2,3,0,0,0}); + std::vector<U8> dec(64, 0xCC); + bool overflow = false; + U32 dec_size = LLZeroCode::decode(src.data(), (U32)src.size(), + dec.data(), (U32)dec.size(), 6, overflow); + ensure_equals("not zero-coded: decode returns 0", dec_size, (U32)0); + ensure("not zero-coded: no overflow", !overflow); + } + + // encode() refuses to write into an undersized destination buffer. + template<> template<> + void zerocode_object::test<9>() + { + std::vector<U8> body(50, 0); + std::vector<U8> src = makeBuffer(1, 0, body); + std::vector<U8> enc(src.size(), 0); // smaller than the required 2 * src_size + S32 r = LLZeroCode::encode(src.data(), (U32)src.size(), enc.data(), (U32)enc.size(), 1); + ensure("encode: capacity guard rejects undersized dst", r < 0); + } + + // decode() reports overflow (rather than writing out of bounds) when dst is too small, + // whether the destination is smaller than a single byte's worth of headroom... + template<> template<> + void zerocode_object::test<10>() + { + std::vector<U8> body(500, 0); + std::vector<U8> src = makeBuffer(1, 0, body); + std::vector<U8> enc(2 * src.size() + 16, 0); + S32 enc_size = LLZeroCode::encode(src.data(), (U32)src.size(), enc.data(), (U32)enc.size(), 1); + ensure("decode overflow setup: encode succeeded", enc_size >= 0); + + std::vector<U8> dec(1, 0); // capacity == header_size exactly + bool overflow = false; + U32 dec_size = LLZeroCode::decode(enc.data(), (U32)enc_size, + dec.data(), (U32)dec.size(), 1, overflow); + ensure("decode overflow (minimal capacity): overflow flagged", overflow); + ensure("decode overflow (minimal capacity): size bounded by capacity", dec_size <= dec.size()); + } + + // ...or comfortably larger than 256 bytes but still short of the true decoded size. + template<> template<> + void zerocode_object::test<11>() + { + std::vector<U8> body(500, 0); + std::vector<U8> src = makeBuffer(1, 0, body); + std::vector<U8> enc(2 * src.size() + 16, 0); + S32 enc_size = LLZeroCode::encode(src.data(), (U32)src.size(), enc.data(), (U32)enc.size(), 1); + ensure("decode overflow setup: encode succeeded", enc_size >= 0); + + std::vector<U8> dec(300, 0); // > 256, but less than the true decoded size (~501) + bool overflow = false; + U32 dec_size = LLZeroCode::decode(enc.data(), (U32)enc_size, + dec.data(), (U32)dec.size(), 1, overflow); + ensure("decode overflow (insufficient capacity): overflow flagged", overflow); + ensure("decode overflow (insufficient capacity): size bounded by capacity", dec_size <= dec.size()); + } + + // A pathological alternating zero/non-zero pattern grows under zero-coding + // (every isolated zero costs 2 output bytes for 1 input byte), so encode + // must refuse it and leave the original buffer in use. + template<> template<> + void zerocode_object::test<12>() + { + std::vector<U8> body; + for (int i = 0; i < 200; ++i) + { + body.push_back(0); + body.push_back((U8)(i + 1)); + } + ensureRoundTrip("alternating pattern", 1, 0x00, body, false); + } +} |