diff options
| -rw-r--r-- | src/streams.h | 24 | ||||
| -rw-r--r-- | src/test/streams_tests.cpp | 244 |
2 files changed, 257 insertions, 11 deletions
diff --git a/src/streams.h b/src/streams.h index 4e600f1826..517eefc932 100644 --- a/src/streams.h +++ b/src/streams.h @@ -735,16 +735,17 @@ protected: size_t nBytes = fread((void*)&vchBuf[pos], 1, readNow, src); if (nBytes == 0) { throw std::ios_base::failure(feof(src) ? "CBufferedFile::Fill: end of file" : "CBufferedFile::Fill: fread failed"); - } else { - nSrcPos += nBytes; - return true; } + nSrcPos += nBytes; + return true; } public: CBufferedFile(FILE *fileIn, uint64_t nBufSize, uint64_t nRewindIn, int nTypeIn, int nVersionIn) : nType(nTypeIn), nVersion(nVersionIn), nSrcPos(0), nReadPos(0), nReadLimit(std::numeric_limits<uint64_t>::max()), nRewind(nRewindIn), vchBuf(nBufSize, 0) { + if (nRewindIn >= nBufSize) + throw std::ios_base::failure("Rewind limit must be less than buffer size"); src = fileIn; } @@ -777,8 +778,6 @@ public: void read(char *pch, size_t nSize) { if (nSize + nReadPos > nReadLimit) throw std::ios_base::failure("Read attempted past buffer limit"); - if (nSize + nRewind > vchBuf.size()) - throw std::ios_base::failure("Read larger than buffer size"); while (nSize > 0) { if (nReadPos == nSrcPos) Fill(); @@ -802,16 +801,19 @@ public: //! rewind to a given reading position bool SetPos(uint64_t nPos) { - nReadPos = nPos; - if (nReadPos + nRewind < nSrcPos) { - nReadPos = nSrcPos - nRewind; + size_t bufsize = vchBuf.size(); + if (nPos + bufsize < nSrcPos) { + // rewinding too far, rewind as far as possible + nReadPos = nSrcPos - bufsize; return false; - } else if (nReadPos > nSrcPos) { + } + if (nPos > nSrcPos) { + // can't go this far forward, go as far as possible nReadPos = nSrcPos; return false; - } else { - return true; } + nReadPos = nPos; + return true; } bool Seek(uint64_t nPos) { diff --git a/src/test/streams_tests.cpp b/src/test/streams_tests.cpp index b812cef801..638819d564 100644 --- a/src/test/streams_tests.cpp +++ b/src/test/streams_tests.cpp @@ -2,6 +2,7 @@ // Distributed under the MIT software license, see the accompanying // file COPYING or http://www.opensource.org/licenses/mit-license.php. +#include <random.h> #include <streams.h> #include <test/setup_common.h> @@ -202,4 +203,247 @@ BOOST_AUTO_TEST_CASE(streams_serializedata_xor) std::string(ds.begin(), ds.end())); } +BOOST_AUTO_TEST_CASE(streams_buffered_file) +{ + FILE* file = fsbridge::fopen("streams_test_tmp", "w+b"); + // The value at each offset is the offset. + for (uint8_t j = 0; j < 40; ++j) { + fwrite(&j, 1, 1, file); + } + rewind(file); + + // The buffer size (second arg) must be greater than the rewind + // amount (third arg). + try { + CBufferedFile bfbad(file, 25, 25, 222, 333); + BOOST_CHECK(false); + } catch (const std::exception& e) { + BOOST_CHECK(strstr(e.what(), + "Rewind limit must be less than buffer size") != nullptr); + } + + // The buffer is 25 bytes, allow rewinding 10 bytes. + CBufferedFile bf(file, 25, 10, 222, 333); + BOOST_CHECK(!bf.eof()); + + // These two members have no functional effect. + BOOST_CHECK_EQUAL(bf.GetType(), 222); + BOOST_CHECK_EQUAL(bf.GetVersion(), 333); + + uint8_t i; + bf >> i; + BOOST_CHECK_EQUAL(i, 0); + bf >> i; + BOOST_CHECK_EQUAL(i, 1); + + // After reading bytes 0 and 1, we're positioned at 2. + BOOST_CHECK_EQUAL(bf.GetPos(), 2); + + // Rewind to offset 0, ok (within the 10 byte window). + BOOST_CHECK(bf.SetPos(0)); + bf >> i; + BOOST_CHECK_EQUAL(i, 0); + + // We can go forward to where we've been, but beyond may fail. + BOOST_CHECK(bf.SetPos(2)); + bf >> i; + BOOST_CHECK_EQUAL(i, 2); + + // If you know the maximum number of bytes that should be + // read to deserialize the variable, you can limit the read + // extent. The current file offset is 3, so the following + // SetLimit() allows zero bytes to be read. + BOOST_CHECK(bf.SetLimit(3)); + try { + bf >> i; + BOOST_CHECK(false); + } catch (const std::exception& e) { + BOOST_CHECK(strstr(e.what(), + "Read attempted past buffer limit") != nullptr); + } + // The default argument removes the limit completely. + BOOST_CHECK(bf.SetLimit()); + // The read position should still be at 3 (no change). + BOOST_CHECK_EQUAL(bf.GetPos(), 3); + + // Read from current offset, 3, forward until position 10. + for (uint8_t j = 3; j < 10; ++j) { + bf >> i; + BOOST_CHECK_EQUAL(i, j); + } + BOOST_CHECK_EQUAL(bf.GetPos(), 10); + + // We're guaranteed (just barely) to be able to rewind to zero. + BOOST_CHECK(bf.SetPos(0)); + BOOST_CHECK_EQUAL(bf.GetPos(), 0); + bf >> i; + BOOST_CHECK_EQUAL(i, 0); + + // We can set the position forward again up to the farthest + // into the stream we've been, but no farther. (Attempting + // to go farther may succeed, but it's not guaranteed.) + BOOST_CHECK(bf.SetPos(10)); + bf >> i; + BOOST_CHECK_EQUAL(i, 10); + BOOST_CHECK_EQUAL(bf.GetPos(), 11); + + // Now it's only guaranteed that we can rewind to offset 1 + // (current read position, 11, minus rewind amount, 10). + BOOST_CHECK(bf.SetPos(1)); + BOOST_CHECK_EQUAL(bf.GetPos(), 1); + bf >> i; + BOOST_CHECK_EQUAL(i, 1); + + // We can stream into large variables, even larger than + // the buffer size. + BOOST_CHECK(bf.SetPos(11)); + { + uint8_t a[40 - 11]; + bf >> a; + for (uint8_t j = 0; j < sizeof(a); ++j) { + BOOST_CHECK_EQUAL(a[j], 11 + j); + } + } + BOOST_CHECK_EQUAL(bf.GetPos(), 40); + + // We've read the entire file, the next read should throw. + try { + bf >> i; + BOOST_CHECK(false); + } catch (const std::exception& e) { + BOOST_CHECK(strstr(e.what(), + "CBufferedFile::Fill: end of file") != nullptr); + } + // Attempting to read beyond the end sets the EOF indicator. + BOOST_CHECK(bf.eof()); + + // Still at offset 40, we can go back 10, to 30. + BOOST_CHECK_EQUAL(bf.GetPos(), 40); + BOOST_CHECK(bf.SetPos(30)); + bf >> i; + BOOST_CHECK_EQUAL(i, 30); + BOOST_CHECK_EQUAL(bf.GetPos(), 31); + + // We're too far to rewind to position zero. + BOOST_CHECK(!bf.SetPos(0)); + // But we should now be positioned at least as far back as allowed + // by the rewind window (relative to our farthest read position, 40). + BOOST_CHECK(bf.GetPos() <= 30); + + // We can explicitly close the file, or the destructor will do it. + bf.fclose(); + + fs::remove("streams_test_tmp"); +} + +BOOST_AUTO_TEST_CASE(streams_buffered_file_rand) +{ + // Make this test deterministic. + SeedInsecureRand(true); + + for (int rep = 0; rep < 50; ++rep) { + FILE* file = fsbridge::fopen("streams_test_tmp", "w+b"); + size_t fileSize = InsecureRandRange(256); + for (uint8_t i = 0; i < fileSize; ++i) { + fwrite(&i, 1, 1, file); + } + rewind(file); + + size_t bufSize = InsecureRandRange(300) + 1; + size_t rewindSize = InsecureRandRange(bufSize); + CBufferedFile bf(file, bufSize, rewindSize, 222, 333); + size_t currentPos = 0; + size_t maxPos = 0; + for (int step = 0; step < 100; ++step) { + if (currentPos >= fileSize) + break; + + // We haven't read to the end of the file yet. + BOOST_CHECK(!bf.eof()); + BOOST_CHECK_EQUAL(bf.GetPos(), currentPos); + + // Pretend the file consists of a series of objects of varying + // sizes; the boundaries of the objects can interact arbitrarily + // with the CBufferFile's internal buffer. These first three + // cases simulate objects of various sizes (1, 2, 5 bytes). + switch (InsecureRandRange(5)) { + case 0: { + uint8_t a[1]; + if (currentPos + 1 > fileSize) + continue; + bf.SetLimit(currentPos + 1); + bf >> a; + for (uint8_t i = 0; i < 1; ++i) { + BOOST_CHECK_EQUAL(a[i], currentPos); + currentPos++; + } + break; + } + case 1: { + uint8_t a[2]; + if (currentPos + 2 > fileSize) + continue; + bf.SetLimit(currentPos + 2); + bf >> a; + for (uint8_t i = 0; i < 2; ++i) { + BOOST_CHECK_EQUAL(a[i], currentPos); + currentPos++; + } + break; + } + case 2: { + uint8_t a[5]; + if (currentPos + 5 > fileSize) + continue; + bf.SetLimit(currentPos + 5); + bf >> a; + for (uint8_t i = 0; i < 5; ++i) { + BOOST_CHECK_EQUAL(a[i], currentPos); + currentPos++; + } + break; + } + case 3: { + // Find a byte value (that is at or ahead of the current position). + size_t find = currentPos + InsecureRandRange(8); + if (find >= fileSize) + find = fileSize - 1; + bf.FindByte(static_cast<char>(find)); + // The value at each offset is the offset. + BOOST_CHECK_EQUAL(bf.GetPos(), find); + currentPos = find; + + bf.SetLimit(currentPos + 1); + uint8_t i; + bf >> i; + BOOST_CHECK_EQUAL(i, currentPos); + currentPos++; + break; + } + case 4: { + size_t requestPos = InsecureRandRange(maxPos + 4); + bool okay = bf.SetPos(requestPos); + // The new position may differ from the requested position + // because we may not be able to rewind beyond the rewind + // window, and we may not be able to move forward beyond the + // farthest position we've reached so far. + currentPos = bf.GetPos(); + BOOST_CHECK_EQUAL(okay, currentPos == requestPos); + // Check that we can position within the rewind window. + if (requestPos <= maxPos && + maxPos > rewindSize && + requestPos >= maxPos - rewindSize) { + // We requested a position within the rewind window. + BOOST_CHECK(okay); + } + break; + } + } + if (maxPos < currentPos) + maxPos = currentPos; + } + } + fs::remove("streams_test_tmp"); +} + BOOST_AUTO_TEST_SUITE_END() |