Move Courgette...

courgette/third_party/bsdiff_apply.cc

Index: courgette/third_party/bsdiff_apply.cc
===================================================================
--- courgette/third_party/bsdiff_apply.cc	(revision 0)
+++ courgette/third_party/bsdiff_apply.cc	(revision 0)
@@ -0,0 +1,165 @@
+/*-
+ * Copyright 2003,2004 Colin Percival
+ * All rights reserved
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted providing that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ *
+ * Changelog:
+ * 2009-03-31 - Change to use Streams.  Move CRC code to crc.{h,cc}
+ *                --Stephen Adams <sra@chromium.org>
+ */
+
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "courgette/third_party/bsdiff.h"
+
+#include "courgette/crc.h"
+#include "courgette/streams.h"
+
+namespace courgette {
+
+BSDiffStatus MBS_ReadHeader(SourceStream* stream, MBSPatchHeader* header) {
+  if (!stream->Read(header->tag, sizeof(header->tag))) return READ_ERROR;
+  if (!stream->ReadVarint32(&header->slen)) return READ_ERROR;
+  if (!stream->ReadVarint32(&header->scrc32)) return READ_ERROR;
+  if (!stream->ReadVarint32(&header->dlen)) return READ_ERROR;
+  if (!stream->ReadVarint32(&header->cblen)) return READ_ERROR;
+  if (!stream->ReadVarint32(&header->difflen)) return READ_ERROR;
+  if (!stream->ReadVarint32(&header->extralen)) return READ_ERROR;
+
+  // The string will have a NUL terminator that we don't use, hence '-1'.
+  COMPILE_ASSERT(sizeof(MBS_PATCH_HEADER_TAG) - 1 == sizeof(header->tag),
+                 MBS_PATCH_HEADER_TAG_must_match_header_field_size);
+  if (memcmp(header->tag, MBS_PATCH_HEADER_TAG, 8) != 0)
+    return UNEXPECTED_ERROR;
+
+  size_t bytes_remaining = stream->Remaining();
+  if (header->cblen +
+      header->difflen +
+      header->extralen != bytes_remaining)
+    return UNEXPECTED_ERROR;
+
+  return OK;
+}
+
+BSDiffStatus MBS_ApplyPatch(const MBSPatchHeader *header,
+                            SourceStream* patch_stream,
+                            const uint8* old_start, size_t old_size,
+                            SinkStream* new_stream) {
+  const uint8* old_end = old_start + old_size;
+
+  SourceStream control_stream;
+
+  const uint8* control_start = patch_stream->Buffer();
+  if (!patch_stream->ReadSubstream(header->cblen, &control_stream))
+    return READ_ERROR;
+  if (!patch_stream->Skip(header->difflen + header->extralen))
+    return READ_ERROR;
+  if (!patch_stream->Empty())
+    return READ_ERROR;
+
+  const uint8* diff_start = control_start + header->cblen;
+  const uint8* diff_end = diff_start + header->difflen;
+  const uint8* extra_start = diff_end;
+  const uint8* extra_end = extra_start + header->extralen;
+
+  const uint8* old_position = old_start;
+  const uint8* diff_position = diff_start;
+  const uint8* extra_position = extra_start;
+
+  new_stream->Reserve(header->dlen);
+
+  while (!control_stream.Empty()) {
+    uint32 copy_count, extra_count;
+    int32 seek_adjustment;
+    if (!control_stream.ReadVarint32(&copy_count))
+      return UNEXPECTED_ERROR;
+    if (!control_stream.ReadVarint32(&extra_count))
+      return UNEXPECTED_ERROR;
+    if (!control_stream.ReadVarint32Signed(&seek_adjustment))
+      return UNEXPECTED_ERROR;
+
+#ifdef DEBUG_bsmedberg
+    printf("Applying block:  copy: %-8u extra: %-8u seek: %+i\n",
+           copy_count, extra_count, seek_adjustment);
+#endif
+    // Byte-wise arithmetically add bytes from old file to bytes from the diff
+    // block.
+    if (copy_count > static_cast<size_t>(old_end - old_position))
+      return UNEXPECTED_ERROR;
+    if (copy_count > static_cast<size_t>(diff_end - diff_position))
+      return UNEXPECTED_ERROR;
+
+    // Add together bytes from the 'old' file and the 'diff' stream.
+    for (size_t i = 0;  i < copy_count;  ++i) {
+      uint8 byte = old_position[i] + diff_position[i];
+      new_stream->Write(&byte, 1);
+    }
+    old_position += copy_count;
+    diff_position += copy_count;
+
+    // Copy bytes from the extra block.
+    if (extra_count > static_cast<size_t>(extra_end - extra_position))
+      return UNEXPECTED_ERROR;
+
+    new_stream->Write(extra_position, extra_count);
+    extra_position += extra_count;
+
+    // "seek" forwards (or backwards) in oldfile.
+    if (old_position + seek_adjustment < old_start ||
+        old_position + seek_adjustment > old_end)
+      return UNEXPECTED_ERROR;
+
+    old_position += seek_adjustment;
+  }
+
+  if (diff_position != diff_end)
+    return UNEXPECTED_ERROR;
+  if (extra_position != extra_end)
+    return UNEXPECTED_ERROR;
+
+  return OK;
+}
+
+BSDiffStatus ApplyBinaryPatch(SourceStream* old_stream,
+                              SourceStream* patch_stream,
+                              SinkStream* new_stream) {
+  MBSPatchHeader header;
+  BSDiffStatus ret = MBS_ReadHeader(patch_stream, &header);
+  if (ret != OK) return ret;
+
+  const uint8* old_start = old_stream->Buffer();
+  size_t old_size = old_stream->Remaining();
+
+  if (old_size != header.slen) return UNEXPECTED_ERROR;
+
+  if (CalculateCrc(old_start, old_size) != header.scrc32)
+    return CRC_ERROR;
+
+  MBS_ApplyPatch(&header, patch_stream, old_start, old_size, new_stream);
+
+  return OK;
+}
+
+}  // namespace