1 files changed, 127 insertions, 0 deletions
diff --git a/cpputil/databuffer.cc b/cpputil/databuffer.cc
new file mode 100644
index 000000000..d60ebccb3
--- /dev/null
+++ b/cpputil/databuffer.cc
@@ -0,0 +1,127 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "databuffer.h"
+#include <algorithm>
+#include <cassert>
+#include <cstring>
+#include <iomanip>
+#include <iostream>
+#if defined(WIN32) || defined(WIN64)
+#include <winsock2.h>
+#else
+#include <arpa/inet.h>
+#endif
+
+namespace nss_test {
+
+void DataBuffer::Assign(const uint8_t* data, size_t len) {
+  if (data) {
+    Allocate(len);
+    memcpy(static_cast<void*>(data_), static_cast<const void*>(data), len);
+  } else {
+    assert(len == 0);
+    data_ = nullptr;
+    len_ = 0;
+  }
+}
+
+// Write will do a new allocation and expand the size of the buffer if needed.
+// Returns the offset of the end of the write.
+size_t DataBuffer::Write(size_t index, const uint8_t* val, size_t count) {
+  assert(val);
+  if (index + count > len_) {
+    size_t newlen = index + count;
+    uint8_t* tmp = new uint8_t[newlen];  // Always > 0.
+    if (data_) {
+      memcpy(static_cast<void*>(tmp), static_cast<const void*>(data_), len_);
+    }
+    if (index > len_) {
+      memset(static_cast<void*>(tmp + len_), 0, index - len_);
+    }
+    delete[] data_;
+    data_ = tmp;
+    len_ = newlen;
+  }
+  if (data_) {
+    memcpy(static_cast<void*>(data_ + index), static_cast<const void*>(val),
+           count);
+  }
+  return index + count;
+}
+
+// Write an integer, also performing host-to-network order conversion.
+// Returns the offset of the end of the write.
+size_t DataBuffer::Write(size_t index, uint32_t val, size_t count) {
+  assert(count <= sizeof(uint32_t));
+  uint32_t nvalue = htonl(val);
+  auto* addr = reinterpret_cast<const uint8_t*>(&nvalue);
+  return Write(index, addr + sizeof(uint32_t) - count, count);
+}
+
+void DataBuffer::Splice(const uint8_t* ins, size_t ins_len, size_t index,
+                        size_t remove) {
+  assert(ins);
+  uint8_t* old_value = data_;
+  size_t old_len = len_;
+
+  // The amount of stuff remaining from the tail of the old.
+  size_t tail_len = old_len - (std::min)(old_len, index + remove);
+  // The new length: the head of the old, the new, and the tail of the old.
+  len_ = index + ins_len + tail_len;
+  data_ = new uint8_t[len_ ? len_ : 1];
+
+  // The head of the old.
+  if (old_value) {
+    Write(0, old_value, (std::min)(old_len, index));
+  }
+  // Maybe a gap.
+  if (old_value && index > old_len) {
+    memset(old_value + index, 0, index - old_len);
+  }
+  // The new.
+  Write(index, ins, ins_len);
+  // The tail of the old.
+  if (tail_len > 0) {
+    Write(index + ins_len, old_value + index + remove, tail_len);
+  }
+
+  delete[] old_value;
+}
+
+// This can't use the same trick as Write(), since we might be reading from a
+// smaller data source.
+bool DataBuffer::Read(size_t index, size_t count, uint64_t* val) const {
+  assert(count <= sizeof(uint64_t));
+  assert(val);
+  if ((index > len()) || (count > (len() - index))) {
+    return false;
+  }
+  *val = 0;
+  for (size_t i = 0; i < count; ++i) {
+    *val = (*val << 8) | data()[index + i];
+  }
+  return true;
+}
+
+bool DataBuffer::Read(size_t index, size_t count, uint32_t* val) const {
+  assert(count <= sizeof(uint32_t));
+  uint64_t tmp;
+
+  if (!Read(index, count, &tmp)) {
+    return false;
+  }
+  *val = tmp & 0xffffffff;
+  return true;
+}
+
+size_t DataBuffer::logging_limit = 32;
+
+/* static */ void DataBuffer::SetLogLimit(size_t limit) {
+  DataBuffer::logging_limit = limit;
+}
+
+}  // namespace nss_test