diff options
Diffstat (limited to 'toolkit/crashreporter/google-breakpad/src/common/linux/crc32.cc')
-rw-r--r-- | toolkit/crashreporter/google-breakpad/src/common/linux/crc32.cc | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/toolkit/crashreporter/google-breakpad/src/common/linux/crc32.cc b/toolkit/crashreporter/google-breakpad/src/common/linux/crc32.cc new file mode 100644 index 0000000000..8df636ce4d --- /dev/null +++ b/toolkit/crashreporter/google-breakpad/src/common/linux/crc32.cc @@ -0,0 +1,70 @@ +// Copyright 2014 Google Inc. +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +#include "common/linux/crc32.h" + +namespace google_breakpad { + +// This implementation is based on the sample implementation in RFC 1952. + +// CRC32 polynomial, in reversed form. +// See RFC 1952, or http://en.wikipedia.org/wiki/Cyclic_redundancy_check +static const uint32_t kCrc32Polynomial = 0xEDB88320; +static uint32_t kCrc32Table[256] = { 0 }; + +#define arraysize(f) (sizeof(f) / sizeof(*f)) + +static void EnsureCrc32TableInited() { + if (kCrc32Table[arraysize(kCrc32Table) - 1]) + return; // already inited + for (uint32_t i = 0; i < arraysize(kCrc32Table); ++i) { + uint32_t c = i; + for (size_t j = 0; j < 8; ++j) { + if (c & 1) { + c = kCrc32Polynomial ^ (c >> 1); + } else { + c >>= 1; + } + } + kCrc32Table[i] = c; + } +} + +uint32_t UpdateCrc32(uint32_t start, const void* buf, size_t len) { + EnsureCrc32TableInited(); + + uint32_t c = start ^ 0xFFFFFFFF; + const uint8_t* u = static_cast<const uint8_t*>(buf); + for (size_t i = 0; i < len; ++i) { + c = kCrc32Table[(c ^ u[i]) & 0xFF] ^ (c >> 8); + } + return c ^ 0xFFFFFFFF; +} + +} // namespace google_breakpad |