AU: Bzip2 utility functions that mirror Gzip utility functions.

src/platform/update_engine/bzip.cc

+// Copyright (c) 2010 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 "update_engine/gzip.h"
+#include <stdlib.h>
+#include <algorithm>
+#include <bzlib.h>
+#include "update_engine/utils.h"
+
+using std::max;
+using std::string;
+using std::vector;
+
+namespace chromeos_update_engine {
+
+int BzipBuffToBuffDecompress(char* out,
+                             size_t* out_length,
+                             const char* in,
+                             size_t in_length) {
+  return BZ2_bzBuffToBuffDecompress(out,
+                                    out_length,
+                                    const_cast<char*>(in),
+                                    in_length,
+                                    0,  // Silent verbosity
+                                    0);  // Normal algorithm
+}
+
+int BzipBuffToBuffCompress(char* out,
+                           size_t* out_length,
+                           const char* in,
+                           size_t in_length) {
+  return BZ2_bzBuffToBuffCompress(out,
+                                  out_length,
+                                  const_cast<char*>(in),
+                                  in_length,
+                                  9,  // Best compression
+                                  0,  // Silent verbosity
+                                  0);  // Default work factor
+}
+
+template<int F(char* out,
+               size_t* out_length,
+               const char* in,
+               size_t in_length)>
+bool BzipData(const char* const in,
+              const size_t in_size,
+              vector<char>* const out) {
+  TEST_AND_RETURN_FALSE(out);
+  out->clear();
+  if (in_size == 0) {
+    return true;
+  }
+  // Try increasing buffer size until it works
+  size_t buf_size = in_size;
+  out->resize(buf_size);
+  
+  for (;;) {
+    size_t data_size = buf_size;
+    int rc = F(&(*out)[0], &data_size, in, in_size);
+    TEST_AND_RETURN_FALSE(rc == BZ_OUTBUFF_FULL || rc == BZ_OK);
+    if (rc == BZ_OK) {
+      // we're done!
+      out->resize(data_size);
+      return true;
+    }
+    
+    // Data didn't fit; double the buffer size.
+    buf_size *= 2;
+    out->resize(buf_size);
+  }
+}
+
+
+bool BzipDecompress(const std::vector<char>& in, std::vector<char>* out) {
+  return BzipData<BzipBuffToBuffDecompress>(&in[0], in.size(), out);
+}
+
+bool BzipCompress(const std::vector<char>& in, std::vector<char>* out) {
+  return BzipData<BzipBuffToBuffCompress>(&in[0], in.size(), out);
+}
+
+namespace {
+template<bool F(const char* const in,
+                const size_t in_size,
+                vector<char>* const out)>
+bool BzipString(const std::string& str,
+                std::vector<char>* out) {
+  TEST_AND_RETURN_FALSE(out);
+  vector<char> temp;
+  TEST_AND_RETURN_FALSE(F(str.data(),
+                          str.size(),
+                          &temp));
+  out->clear();
+  out->insert(out->end(), temp.begin(), temp.end());
+  return true;
+}
+}  // namespace {}
+
+bool BzipCompressString(const std::string& str,
+                        std::vector<char>* out) {
+  return BzipString<BzipData<BzipBuffToBuffCompress> >(str, out);
+}
+
+bool BzipDecompressString(const std::string& str,
+                          std::vector<char>* out) {
+  return BzipString<BzipData<BzipBuffToBuffDecompress> >(str, out);
+}
+
+} // namespace chromeos_update_engine