Breakpad symbol dumper: Define the ByteBuffer and ByteCursor classes.

The ByteBuffer and ByteCursor classes are utility classes for reading
binary files, handling endianness and word size issues in a portable way.

a=jimblandy, r=thestig


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@582 4c0a9323-5329-0410-9bdc-e9ce6186880e

3 files changed, 1058 insertions, 0 deletions

diff --git a/src/common/byte_cursor.h b/src/common/byte_cursor.h
new file mode 100644
index 00000000..24ffce75
--- /dev/null
+++ b/src/common/byte_cursor.h
@@ -0,0 +1,263 @@
+// -*- mode: c++ -*-
+
+// Copyright (c) 2010, 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.
+
+// Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
+
+// byte_cursor.h: Classes for parsing values from a buffer of bytes.
+// The ByteCursor class provides a convenient interface for reading
+// fixed-size integers of arbitrary endianness, being thorough about
+// checking for buffer overruns.
+
+#ifndef COMMON_BYTE_CURSOR_H_
+#define COMMON_BYTE_CURSOR_H_
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <string>
+
+namespace google_breakpad {
+
+// A buffer holding a series of bytes.
+struct ByteBuffer {
+  ByteBuffer() : start(0), end(0) { }
+  ByteBuffer(const uint8_t *set_start, size_t set_size)
+      : start(set_start), end(set_start + set_size) { }
+  ~ByteBuffer() { };
+
+  // Equality operators. Useful in unit tests, and when we're using
+  // ByteBuffers to refer to regions of a larger buffer.
+  bool operator==(const ByteBuffer &that) const {
+    return start == that.start && end == that.end;
+  }
+  bool operator!=(const ByteBuffer &that) const {
+    return start != that.start || end != that.end;
+  }
+
+  // Not C++ style guide compliant, but this definitely belongs here.
+  size_t Size() const {
+    assert(start <= end);
+    return end - start;
+  }
+
+  const uint8_t *start, *end;
+};
+
+// A cursor pointing into a ByteBuffer that can parse numbers of various
+// widths and representations, strings, and data blocks, advancing through
+// the buffer as it goes. All ByteCursor operations check that accesses
+// haven't gone beyond the end of the enclosing ByteBuffer.
+class ByteCursor {
+ public:
+  // Create a cursor reading bytes from the start of BUFFER. By default, the
+  // cursor reads multi-byte values in little-endian form.
+  ByteCursor(const ByteBuffer *buffer, bool big_endian = false)
+      : buffer_(buffer), here_(buffer->start), 
+        big_endian_(big_endian), complete_(true) { }
+
+  // Accessor and setter for this cursor's endianness flag.
+  bool big_endian() const { return big_endian_; }
+  void set_big_endian(bool big_endian) { big_endian_ = big_endian; }
+
+  // Accessor and setter for this cursor's current position. The setter
+  // returns a reference to this cursor.
+  const uint8_t *here() const { return here_; }
+  ByteCursor &set_here(const uint8_t *here) {
+    assert(buffer_->start <= here && here <= buffer_->end);
+    here_ = here;
+    return *this;
+  }
+
+  // Return the number of bytes available to read at the cursor.
+  size_t Available() const { return size_t(buffer_->end - here_); }
+
+  // Return true if this cursor is at the end of its buffer.
+  bool AtEnd() const { return Available() == 0; }
+
+  // When used as a boolean value this cursor converts to true if all
+  // prior reads have been completed, or false if we ran off the end
+  // of the buffer.
+  operator bool() const { return complete_; }
+
+  // Read a SIZE-byte integer at this cursor, signed if IS_SIGNED is true,
+  // unsigned otherwise, using the cursor's established endianness, and set
+  // *RESULT to the number. If we read off the end of our buffer, clear
+  // this cursor's complete_ flag, and store a dummy value in *RESULT.
+  // Return a reference to this cursor.
+  template<typename T>
+  ByteCursor &Read(size_t size, bool is_signed, T *result) {
+    if (CheckAvailable(size)) {
+      T v = 0;
+      if (big_endian_) {
+        for (size_t i = 0; i < size; i++)
+          v = (v << 8) + here_[i];
+      } else {
+        // This loop condition looks weird, but size_t is unsigned, so
+        // decrementing i after it is zero yields the largest size_t value.
+        for (size_t i = size - 1; i < size; i--)
+          v = (v << 8) + here_[i];
+      }
+      if (is_signed && size < sizeof(T)) {
+        size_t sign_bit = (T)1 << (size * 8 - 1);
+        v = (v ^ sign_bit) - sign_bit;
+      }
+      here_ += size;
+      *result = v;
+    } else {
+      *result = (T) 0xdeadbeef;
+    }
+    return *this;
+  }
+
+  // Read an integer, using the cursor's established endianness and
+  // *RESULT's size and signedness, and set *RESULT to the number. If we
+  // read off the end of our buffer, clear this cursor's complete_ flag.
+  // Return a reference to this cursor.
+  template<typename T>
+  ByteCursor &operator>>(T &result) {
+    bool T_is_signed = (T)-1 < 0;
+    return Read(sizeof(T), T_is_signed, &result); 
+  }
+
+  // Copy the SIZE bytes at the cursor to BUFFER, and advance this
+  // cursor to the end of them. If we read off the end of our buffer,
+  // clear this cursor's complete_ flag, and set *POINTER to NULL.
+  // Return a reference to this cursor.
+  ByteCursor &Read(uint8_t *buffer, size_t size) {
+    if (CheckAvailable(size)) {
+      memcpy(buffer, here_, size);
+      here_ += size;
+    }
+    return *this;
+  }
+
+  // Set STR to a copy of the '\0'-terminated string at the cursor. If the
+  // byte buffer does not contain a terminating zero, clear this cursor's
+  // complete_ flag, and set STR to the empty string. Return a reference to
+  // this cursor.
+  ByteCursor &CString(std::string *str) {
+    const uint8_t *end
+      = static_cast<const uint8_t *>(memchr(here_, '\0', Available()));
+    if (end) {
+      str->assign(reinterpret_cast<const char *>(here_), end - here_);
+      here_ = end + 1;
+    } else {
+      str->clear();
+      here_ = buffer_->end;
+      complete_ = false;
+    }
+    return *this;
+  }
+
+  // Like CString(STR), but extract the string from a fixed-width buffer
+  // LIMIT bytes long, which may or may not contain a terminating '\0'
+  // byte. Specifically:
+  //
+  // - If there are not LIMIT bytes available at the cursor, clear the
+  //   cursor's complete_ flag and set STR to the empty string.
+  //
+  // - Otherwise, if the LIMIT bytes at the cursor contain any '\0'
+  //   characters, set *STR to a copy of the bytes before the first '\0',
+  //   and advance the cursor by LIMIT bytes.
+  //   
+  // - Otherwise, set *STR to a copy of those LIMIT bytes, and advance the
+  //   cursor by LIMIT bytes.
+  ByteCursor &CString(std::string *str, size_t limit) {
+    if (CheckAvailable(limit)) {
+      const uint8_t *end
+        = static_cast<const uint8_t *>(memchr(here_, '\0', limit));
+      if (end)
+        str->assign(reinterpret_cast<const char *>(here_), end - here_);
+      else
+        str->assign(reinterpret_cast<const char *>(here_), limit);
+      here_ += limit;
+    } else {
+      str->clear();
+    }
+    return *this;
+  }
+
+  // Set *POINTER to point to the SIZE bytes at the cursor, and advance
+  // this cursor to the end of them. If SIZE is omitted, don't move the
+  // cursor. If we read off the end of our buffer, clear this cursor's
+  // complete_ flag, and set *POINTER to NULL. Return a reference to this
+  // cursor.
+  ByteCursor &PointTo(const uint8_t **pointer, size_t size = 0) {
+    if (CheckAvailable(size)) {
+      *pointer = here_;
+      here_ += size;
+    } else {
+      *pointer = NULL;
+    }
+    return *this;
+  }
+
+  // Skip SIZE bytes at the cursor. If doing so would advance us off
+  // the end of our buffer, clear this cursor's complete_ flag, and
+  // set *POINTER to NULL. Return a reference to this cursor.
+  ByteCursor &Skip(size_t size) {
+    if (CheckAvailable(size))
+      here_ += size;
+    return *this;
+  }
+
+ private:
+  // If there are at least SIZE bytes available to read from the buffer,
+  // return true. Otherwise, set here_ to the end of the buffer, set
+  // complete_ to false, and return false.
+  bool CheckAvailable(size_t size) {
+    if (Available() >= size) {
+      return true;
+    } else {
+      here_ = buffer_->end;
+      complete_ = false;
+      return false;
+    }
+  }
+
+  // The buffer we're reading bytes from.
+  const ByteBuffer *buffer_;
+
+  // The next byte within buffer_ that we'll read.
+  const uint8_t *here_;
+
+  // True if we should read numbers in big-endian form; false if we
+  // should read in little-endian form.
+  bool big_endian_;
+
+  // True if we've been able to read all we've been asked to.
+  bool complete_;
+};
+
+}  // namespace google_breakpad
+
+#endif  // COMMON_BYTE_CURSOR_H_
diff --git a/src/common/byte_cursor_unittest.cc b/src/common/byte_cursor_unittest.cc
new file mode 100644
index 00000000..0ab4770a
--- /dev/null
+++ b/src/common/byte_cursor_unittest.cc
@@ -0,0 +1,776 @@
+// Copyright (c) 2010 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.
+
+// Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
+
+// byte_cursor_unittest.cc: Unit tests for google_breakpad::ByteBuffer
+// and google_breakpad::ByteCursor.
+
+#include <string>
+
+#include <string.h>
+
+#include "common/byte_cursor.h"
+#include "breakpad_googletest_includes.h"
+
+using google_breakpad::ByteBuffer;
+using google_breakpad::ByteCursor;
+using std::string;
+
+TEST(Buffer, SizeOfNothing) {
+  uint8_t data[1];
+  ByteBuffer buffer(data, 0);
+  EXPECT_EQ(0U, buffer.Size());
+}
+
+TEST(Buffer, SizeOfSomething) {
+  uint8_t data[10];
+  ByteBuffer buffer(data, sizeof(data));
+  EXPECT_EQ(10U, buffer.Size());
+}
+
+TEST(Extent, AvailableEmpty) {
+  uint8_t data[1];
+  ByteBuffer buffer(data, 0);
+  ByteCursor cursor(&buffer);
+  EXPECT_EQ(0U, cursor.Available());
+}
+
+TEST(Extent, AtEndEmpty) {
+  uint8_t data[1];
+  ByteBuffer buffer(data, 0);
+  ByteCursor cursor(&buffer);
+  EXPECT_TRUE(cursor.AtEnd());
+}
+
+TEST(Extent, AsBoolEmpty) {
+  uint8_t data[1];
+  ByteBuffer buffer(data, 0);
+  ByteCursor cursor(&buffer);
+  EXPECT_TRUE(cursor);
+}
+
+TEST(Extent, AvailableSome) {
+  uint8_t data[10];
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  EXPECT_EQ(10U, cursor.Available());
+}
+
+TEST(Extent, AtEndSome) {
+  uint8_t data[10];
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  EXPECT_FALSE(cursor.AtEnd());
+  EXPECT_TRUE(cursor.Skip(sizeof(data)).AtEnd());
+}
+
+TEST(Extent, AsBoolSome) {
+  uint8_t data[10];
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  EXPECT_TRUE(cursor);
+  EXPECT_TRUE(cursor.Skip(sizeof(data)));
+  EXPECT_FALSE(cursor.Skip(1));
+}
+
+TEST(Extent, Cursor) {
+  uint8_t data[] = { 0xf7,
+                     0x9f, 0xbe,
+                     0x67, 0xfb, 0xd3, 0x58,
+                     0x6f, 0x36, 0xde, 0xd1,
+                     0x2a, 0x2a, 0x2a };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+
+  uint8_t a;
+  uint16_t b;
+  uint32_t c;
+  uint32_t d;
+  uint8_t stars[3];
+
+  EXPECT_EQ(data + 0U, cursor.here());
+
+  EXPECT_TRUE(cursor >> a);
+  EXPECT_EQ(data + 1U, cursor.here());
+
+  EXPECT_TRUE(cursor >> b);
+  EXPECT_EQ(data + 3U, cursor.here());
+
+  EXPECT_TRUE(cursor >> c);
+  EXPECT_EQ(data + 7U, cursor.here());
+
+  EXPECT_TRUE(cursor.Skip(4));
+  EXPECT_EQ(data + 11U, cursor.here());
+
+  EXPECT_TRUE(cursor.Read(stars, 3));
+  EXPECT_EQ(data + 14U, cursor.here());
+
+  EXPECT_FALSE(cursor >> d);
+  EXPECT_EQ(data + 14U, cursor.here());
+}
+
+TEST(Extent, SetOffset) {
+  uint8_t data[] = { 0x5c, 0x79, 0x8c, 0xd5 };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+
+  uint8_t a, b, c, d, e;
+  EXPECT_TRUE(cursor >> a);
+  EXPECT_EQ(0x5cU, a);
+  EXPECT_EQ(data + 1U, cursor.here());
+  EXPECT_TRUE(((cursor >> b).set_here(data + 3) >> c).set_here(data + 1)
+              >> d >> e);
+  EXPECT_EQ(0x79U, b);
+  EXPECT_EQ(0xd5U, c);
+  EXPECT_EQ(0x79U, d);
+  EXPECT_EQ(0x8cU, e);
+  EXPECT_EQ(data + 3U, cursor.here());
+}
+
+TEST(BigEndian, Signed1) {
+  uint8_t data[] = { 0x00, 0x7f, 0x80, 0xff };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  cursor.set_big_endian(true);
+  int a, b, c, d, e;
+  ASSERT_TRUE(cursor
+              .Read(1, true, &a)
+              .Read(1, true, &b)
+              .Read(1, true, &c)
+              .Read(1, true, &d));
+  EXPECT_EQ(0,     a);
+  EXPECT_EQ(0x7f,  b);
+  EXPECT_EQ(-0x80, c);
+  EXPECT_EQ(-1,    d);
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(1, true, &e));
+}
+
+TEST(BigEndian, Signed2) {
+  uint8_t data[] = { 0x00, 0x00,   0x00, 0x80,   0x7f, 0xff,
+                     0x80, 0x00,   0x80, 0x80,   0xff, 0xff,
+                     0x39, 0xf1,   0x8a, 0xbc,   0x5a, 0xec };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer, true);
+  int a, b, c, d, e, f, g, h, i, j;
+  ASSERT_TRUE(cursor
+              .Read(2, true, &a)
+              .Read(2, true, &b)
+              .Read(2, true, &c)
+              .Read(2, true, &d)
+              .Read(2, true, &e)
+              .Read(2, true, &f)
+              .Read(2, true, &g)
+              .Read(2, true, &h)
+              .Read(2, true, &i));
+  EXPECT_EQ(0,       a);
+  EXPECT_EQ(0x80,    b);
+  EXPECT_EQ(0x7fff,  c);
+  EXPECT_EQ(-0x8000, d);
+  EXPECT_EQ(-0x7f80, e);
+  EXPECT_EQ(-1,      f);
+  EXPECT_EQ(0x39f1,  g);
+  EXPECT_EQ(-0x7544, h);
+  EXPECT_EQ(0x5aec,  i);
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(2, true, &j));
+}
+
+TEST(BigEndian, Signed4) {
+  uint8_t data[] = { 0x00, 0x00, 0x00, 0x00,
+                     0x7f, 0xff, 0xff, 0xff,
+                     0x80, 0x00, 0x00, 0x00,
+                     0xff, 0xff, 0xff, 0xff,
+                     0xb6, 0xb1, 0xff, 0xef,
+                     0x19, 0x6a, 0xca, 0x46 };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  cursor.set_big_endian(true);
+  int64_t a, b, c, d, e, f, g;
+  ASSERT_TRUE(cursor
+              .Read(4, true, &a)
+              .Read(4, true, &b)
+              .Read(4, true, &c)
+              .Read(4, true, &d)
+              .Read(4, true, &e)
+              .Read(4, true, &f));
+  EXPECT_EQ(0,                    a);
+  EXPECT_EQ(0x7fffffff,           b);
+  EXPECT_EQ(-0x80000000LL,        c);
+  EXPECT_EQ(-1,                   d);
+  EXPECT_EQ((int32_t) 0xb6b1ffef, e);
+  EXPECT_EQ(0x196aca46,           f);
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(4, true, &g));
+}
+
+TEST(BigEndian, Signed8) {
+  uint8_t data[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+                     0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+                     0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+                     0x93, 0x20, 0xd5, 0xe9, 0xd2, 0xd5, 0x87, 0x9c,
+                     0x4e, 0x42, 0x49, 0xd2, 0x7f, 0x84, 0x14, 0xa4 };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer, true);
+  int64_t a, b, c, d, e, f, g;
+  ASSERT_TRUE(cursor
+              .Read(8, true, &a)
+              .Read(8, true, &b)
+              .Read(8, true, &c)
+              .Read(8, true, &d)
+              .Read(8, true, &e)
+              .Read(8, true, &f));
+  EXPECT_EQ(0,                               a);
+  EXPECT_EQ(0x7fffffffffffffffLL,            b);
+  EXPECT_EQ(-0x7fffffffffffffffLL - 1,       c);
+  EXPECT_EQ(-1,                              d);
+  EXPECT_EQ((int64_t) 0x9320d5e9d2d5879cULL, e);
+  EXPECT_EQ(0x4e4249d27f8414a4LL,            f);  
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(8, true, &g));
+}
+
+TEST(BigEndian, Unsigned1) {
+  uint8_t data[] = { 0x00, 0x7f, 0x80, 0xff };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  cursor.set_big_endian(true);
+  int32_t a, b, c, d, e;
+  ASSERT_TRUE(cursor
+              .Read(1, false, &a)
+              .Read(1, false, &b)
+              .Read(1, false, &c)
+              .Read(1, false, &d));
+  EXPECT_EQ(0,    a);
+  EXPECT_EQ(0x7f, b);
+  EXPECT_EQ(0x80, c);
+  EXPECT_EQ(0xff, d);
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(1, false, &e));
+}
+
+TEST(BigEndian, Unsigned2) {
+  uint8_t data[] = { 0x00, 0x00,   0x00, 0x80,   0x7f, 0xff,
+                     0x80, 0x00,   0x80, 0x80,   0xff, 0xff,
+                     0x39, 0xf1,   0x8a, 0xbc,   0x5a, 0xec };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer, true);
+  int64_t a, b, c, d, e, f, g, h, i, j;
+  ASSERT_TRUE(cursor
+              .Read(2, false, &a)
+              .Read(2, false, &b)
+              .Read(2, false, &c)
+              .Read(2, false, &d)
+              .Read(2, false, &e)
+              .Read(2, false, &f)
+              .Read(2, false, &g)
+              .Read(2, false, &h)
+              .Read(2, false, &i));
+  EXPECT_EQ(0,      a);
+  EXPECT_EQ(0x80,   b);
+  EXPECT_EQ(0x7fff, c);
+  EXPECT_EQ(0x8000, d);
+  EXPECT_EQ(0x8080, e);
+  EXPECT_EQ(0xffff, f);
+  EXPECT_EQ(0x39f1, g);
+  EXPECT_EQ(0x8abc, h);
+  EXPECT_EQ(0x5aec, i);
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(2, false, &j));
+}
+
+TEST(BigEndian, Unsigned4) {
+  uint8_t data[] = { 0x00, 0x00, 0x00, 0x00,
+                     0x7f, 0xff, 0xff, 0xff,
+                     0x80, 0x00, 0x00, 0x00,
+                     0xff, 0xff, 0xff, 0xff,
+                     0xb6, 0xb1, 0xff, 0xef,
+                     0x19, 0x6a, 0xca, 0x46 };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  cursor.set_big_endian(true);
+  int64_t a, b, c, d, e, f, g;
+  ASSERT_TRUE(cursor
+              .Read(4, false, &a)
+              .Read(4, false, &b)
+              .Read(4, false, &c)
+              .Read(4, false, &d)
+              .Read(4, false, &e)
+              .Read(4, false, &f));
+  EXPECT_EQ(0,          a);
+  EXPECT_EQ(0x7fffffff, b);
+  EXPECT_EQ(0x80000000, c);
+  EXPECT_EQ(0xffffffff, d);
+  EXPECT_EQ(0xb6b1ffef, e);
+  EXPECT_EQ(0x196aca46, f);
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(4, false, &g));
+}
+
+TEST(BigEndian, Unsigned8) {
+  uint8_t data[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+                     0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+                     0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+                     0x93, 0x20, 0xd5, 0xe9, 0xd2, 0xd5, 0x87, 0x9c,
+                     0x4e, 0x42, 0x49, 0xd2, 0x7f, 0x84, 0x14, 0xa4 };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer, true);
+  uint64_t a, b, c, d, e, f, g;
+  ASSERT_TRUE(cursor
+              .Read(8, false, &a)
+              .Read(8, false, &b)
+              .Read(8, false, &c)
+              .Read(8, false, &d)
+              .Read(8, false, &e)
+              .Read(8, false, &f));
+  EXPECT_EQ(0U,                    a);
+  EXPECT_EQ(0x7fffffffffffffffULL, b);
+  EXPECT_EQ(0x8000000000000000ULL, c);
+  EXPECT_EQ(0xffffffffffffffffULL, d);
+  EXPECT_EQ(0x9320d5e9d2d5879cULL, e);
+  EXPECT_EQ(0x4e4249d27f8414a4ULL, f);  
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(8, false, &g));
+}
+
+TEST(LittleEndian, Signed1) {
+  uint8_t data[] = { 0x00, 0x7f, 0x80, 0xff };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  int32_t a, b, c, d, e;
+  ASSERT_TRUE(cursor
+              .Read(1, true, &a)
+              .Read(1, true, &b)
+              .Read(1, true, &c)
+              .Read(1, true, &d));
+  EXPECT_EQ(0,     a);
+  EXPECT_EQ(0x7f,  b);
+  EXPECT_EQ(-0x80, c);
+  EXPECT_EQ(-1,    d);
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(1, true, &e));
+}
+
+TEST(LittleEndian, Signed2) {
+  uint8_t data[] = { 0x00, 0x00,   0x80, 0x00,   0xff, 0x7f,
+                     0x00, 0x80,   0x80, 0x80,   0xff, 0xff,
+                     0xf1, 0x39,   0xbc, 0x8a,   0xec, 0x5a };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer, false);
+  int32_t a, b, c, d, e, f, g, h, i, j;
+  ASSERT_TRUE(cursor
+              .Read(2, true, &a)
+              .Read(2, true, &b)
+              .Read(2, true, &c)
+              .Read(2, true, &d)
+              .Read(2, true, &e)
+              .Read(2, true, &f)
+              .Read(2, true, &g)
+              .Read(2, true, &h)
+              .Read(2, true, &i));
+  EXPECT_EQ(0,       a);
+  EXPECT_EQ(0x80,    b);
+  EXPECT_EQ(0x7fff,  c);
+  EXPECT_EQ(-0x8000, d);
+  EXPECT_EQ(-0x7f80, e);
+  EXPECT_EQ(-1,      f);
+  EXPECT_EQ(0x39f1,  g);
+  EXPECT_EQ(-0x7544, h);
+  EXPECT_EQ(0x5aec,  i);
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(2, true, &j));
+}
+
+TEST(LittleEndian, Signed4) {
+  uint8_t data[] = { 0x00, 0x00, 0x00, 0x00,
+                     0xff, 0xff, 0xff, 0x7f,
+                     0x00, 0x00, 0x00, 0x80,
+                     0xff, 0xff, 0xff, 0xff,
+                     0xef, 0xff, 0xb1, 0xb6, 
+                     0x46, 0xca, 0x6a, 0x19 };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  int64_t a, b, c, d, e, f, g;
+  ASSERT_TRUE(cursor
+              .Read(4, true, &a)
+              .Read(4, true, &b)
+              .Read(4, true, &c)
+              .Read(4, true, &d)
+              .Read(4, true, &e)
+              .Read(4, true, &f));
+  EXPECT_EQ(0,                    a);
+  EXPECT_EQ(0x7fffffff,           b);
+  EXPECT_EQ(-0x80000000LL,        c);
+  EXPECT_EQ(-1,                   d);
+  EXPECT_EQ((int32_t) 0xb6b1ffef, e);
+  EXPECT_EQ(0x196aca46,           f);
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(4, true, &g));
+}
+
+TEST(LittleEndian, Signed8) {
+  uint8_t data[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+                     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f,
+                     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80,
+                     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+                     0x9c, 0x87, 0xd5, 0xd2, 0xe9, 0xd5, 0x20, 0x93,
+                     0xa4, 0x14, 0x84, 0x7f, 0xd2, 0x49, 0x42, 0x4e };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer, false);
+  int64_t a, b, c, d, e, f, g;
+  ASSERT_TRUE(cursor
+              .Read(8, true, &a)
+              .Read(8, true, &b)
+              .Read(8, true, &c)
+              .Read(8, true, &d)
+              .Read(8, true, &e)
+              .Read(8, true, &f));
+  EXPECT_EQ(0,                               a);
+  EXPECT_EQ(0x7fffffffffffffffLL,            b);
+  EXPECT_EQ(-0x7fffffffffffffffLL - 1,       c);
+  EXPECT_EQ(-1,                              d);
+  EXPECT_EQ((int64_t) 0x9320d5e9d2d5879cULL, e);
+  EXPECT_EQ(0x4e4249d27f8414a4LL,            f);  
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(8, true, &g));
+}
+
+TEST(LittleEndian, Unsigned1) {
+  uint8_t data[] = { 0x00, 0x7f, 0x80, 0xff };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  int32_t a, b, c, d, e;
+  ASSERT_TRUE(cursor
+              .Read(1, false, &a)
+              .Read(1, false, &b)
+              .Read(1, false, &c)
+              .Read(1, false, &d));
+  EXPECT_EQ(0,    a);
+  EXPECT_EQ(0x7f, b);
+  EXPECT_EQ(0x80, c);
+  EXPECT_EQ(0xff, d);
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(1, false, &e));
+}
+
+TEST(LittleEndian, Unsigned2) {
+  uint8_t data[] = { 0x00, 0x00,   0x80, 0x00,   0xff, 0x7f,
+                     0x00, 0x80,   0x80, 0x80,   0xff, 0xff,
+                     0xf1, 0x39,   0xbc, 0x8a,   0xec, 0x5a };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  int32_t a, b, c, d, e, f, g, h, i, j;
+  ASSERT_TRUE(cursor
+              .Read(2, false, &a)
+              .Read(2, false, &b)
+              .Read(2, false, &c)
+              .Read(2, false, &d)
+              .Read(2, false, &e)
+              .Read(2, false, &f)
+              .Read(2, false, &g)
+              .Read(2, false, &h)
+              .Read(2, false, &i));
+  EXPECT_EQ(0,      a);
+  EXPECT_EQ(0x80,   b);
+  EXPECT_EQ(0x7fff, c);
+  EXPECT_EQ(0x8000, d);
+  EXPECT_EQ(0x8080, e);
+  EXPECT_EQ(0xffff, f);
+  EXPECT_EQ(0x39f1, g);
+  EXPECT_EQ(0x8abc, h);
+  EXPECT_EQ(0x5aec, i);
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(2, false, &j));
+}
+
+TEST(LittleEndian, Unsigned4) {
+  uint8_t data[] = { 0x00, 0x00, 0x00, 0x00,
+                     0xff, 0xff, 0xff, 0x7f,
+                     0x00, 0x00, 0x00, 0x80,
+                     0xff, 0xff, 0xff, 0xff,
+                     0xef, 0xff, 0xb1, 0xb6,
+                     0x46, 0xca, 0x6a, 0x19 };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  int64_t a, b, c, d, e, f, g;
+  ASSERT_TRUE(cursor
+              .Read(4, false, &a)
+              .Read(4, false, &b)
+              .Read(4, false, &c)
+              .Read(4, false, &d)
+              .Read(4, false, &e)
+              .Read(4, false, &f));
+  EXPECT_EQ(0,          a);
+  EXPECT_EQ(0x7fffffff, b);
+  EXPECT_EQ(0x80000000, c);
+  EXPECT_EQ(0xffffffff, d);
+  EXPECT_EQ(0xb6b1ffef, e);
+  EXPECT_EQ(0x196aca46, f);
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(4, false, &g));
+}
+
+TEST(LittleEndian, Unsigned8) {
+  uint8_t data[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+                     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f,
+                     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80,
+                     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+                     0x9c, 0x87, 0xd5, 0xd2, 0xe9, 0xd5, 0x20, 0x93,
+                     0xa4, 0x14, 0x84, 0x7f, 0xd2, 0x49, 0x42, 0x4e };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  uint64_t a, b, c, d, e, f, g;
+  ASSERT_TRUE(cursor
+              .Read(8, false, &a)
+              .Read(8, false, &b)
+              .Read(8, false, &c)
+              .Read(8, false, &d)
+              .Read(8, false, &e)
+              .Read(8, false, &f));
+  EXPECT_EQ(0U,                    a);
+  EXPECT_EQ(0x7fffffffffffffffULL, b);
+  EXPECT_EQ(0x8000000000000000ULL, c);
+  EXPECT_EQ(0xffffffffffffffffULL, d);
+  EXPECT_EQ(0x9320d5e9d2d5879cULL, e);
+  EXPECT_EQ(0x4e4249d27f8414a4ULL, f);  
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor.Read(8, false, &g));
+}
+
+TEST(Extractor, Signed1) {
+  uint8_t data[] = { 0xfd };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  int8_t a;
+  EXPECT_TRUE(cursor >> a);
+  EXPECT_EQ(-3, a);
+  EXPECT_FALSE(cursor >> a);
+}
+
+TEST(Extractor, Signed2) {
+  uint8_t data[] = { 0x13, 0xcd };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  int16_t a;
+  EXPECT_TRUE(cursor >> a);
+  EXPECT_EQ(-13037, a);
+  EXPECT_FALSE(cursor >> a);
+}
+
+TEST(Extractor, Signed4) {
+  uint8_t data[] = { 0xd2, 0xe4, 0x53, 0xe9 };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  int32_t a;
+  // For some reason, G++ 4.4.1 complains:
+  //   warning: array subscript is above array bounds
+  // in ByteCursor::Read(size_t, bool, T *) as it inlines this call, but
+  // I'm not able to see how such a reference would occur.
+  EXPECT_TRUE(cursor >> a);
+  EXPECT_EQ(-380377902, a);
+  EXPECT_FALSE(cursor >> a);
+}
+
+TEST(Extractor, Unsigned1) {
+  uint8_t data[] = { 0xfd };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  uint8_t a;
+  EXPECT_TRUE(cursor >> a);
+  EXPECT_EQ(0xfd, a);
+  EXPECT_FALSE(cursor >> a);
+}
+
+TEST(Extractor, Unsigned2) {
+  uint8_t data[] = { 0x13, 0xcd };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  uint16_t a;
+  EXPECT_TRUE(cursor >> a);
+  EXPECT_EQ(0xcd13, a);
+  EXPECT_FALSE(cursor >> a);
+}
+
+TEST(Extractor, Unsigned4) {
+  uint8_t data[] = { 0xd2, 0xe4, 0x53, 0xe9 };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  uint32_t a;
+  // For some reason, G++ 4.4.1 complains:
+  //   warning: array subscript is above array bounds
+  // in ByteCursor::Read(size_t, bool, T *) as it inlines this call, but
+  // I'm not able to see how such a reference would occur.
+  EXPECT_TRUE(cursor >> a);
+  EXPECT_EQ(0xe953e4d2, a);
+  EXPECT_FALSE(cursor >> a);
+  EXPECT_FALSE(cursor >> a);
+}
+
+TEST(Extractor, Mixed) {
+  uint8_t data[] = { 0x42,
+                     0x25, 0x0b,
+                     0x3d, 0x25, 0xed, 0x2a,
+                     0xec, 0x16, 0x9e, 0x14, 0x61, 0x5b, 0x2c, 0xcf,
+                     0xd8,
+                     0x22, 0xa5,
+                     0x3a, 0x02, 0x6a, 0xd7,
+                     0x93, 0x2a, 0x2d, 0x8d, 0xb4, 0x95, 0xe0, 0xc6 };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+  cursor.set_big_endian(true);
+
+  uint8_t a;
+  uint16_t b;
+  uint32_t c;
+  uint64_t d;
+  int8_t e;
+  int16_t f;
+  int32_t g;
+  int64_t h;
+  int z;
+  EXPECT_FALSE(cursor.AtEnd());
+  EXPECT_TRUE(cursor >> a >> b >> c >> d >> e >> f >> g >> h);
+  EXPECT_EQ(0x42U, a);
+  EXPECT_EQ(0x250bU, b);
+  EXPECT_EQ(0x3d25ed2aU, c);
+  EXPECT_EQ(0xec169e14615b2ccfULL, d);
+  EXPECT_EQ(-40, e);
+  EXPECT_EQ(0x22a5, f);
+  EXPECT_EQ(0x3a026ad7, g);
+  EXPECT_EQ(-7842405714468937530LL, h);
+
+  EXPECT_TRUE(cursor.AtEnd());
+  EXPECT_FALSE(cursor >> z);
+}
+
+TEST(Strings, Zero) {
+  uint8_t data[] = { 0xa6 };
+  ByteBuffer buffer(data, 0);
+  ByteCursor cursor(&buffer);
+
+  uint8_t received[1];
+  received[0] = 0xc2;
+  EXPECT_TRUE(cursor.Read(received, 0));
+  EXPECT_EQ(0xc2U, received[0]);
+}
+
+TEST(Strings, Some) {
+  uint8_t data[] = { 0x5d, 0x31, 0x09, 0xa6, 0x2e, 0x2c, 0x83, 0xbb };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+
+  uint8_t received[7] = { 0xa7, 0xf7, 0x43, 0x0c, 0x27, 0xea, 0xed };
+  EXPECT_TRUE(cursor.Skip(2).Read(received, 5));
+  uint8_t expected[7] = { 0x09, 0xa6, 0x2e, 0x2c, 0x83, 0xea, 0xed };
+  EXPECT_TRUE(memcmp(received, expected, 7) == 0);
+}
+
+TEST(Strings, TooMuch) {
+  uint8_t data[] = { 0x5d, 0x31, 0x09, 0xa6, 0x2e, 0x2c, 0x83, 0xbb };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+
+  uint8_t received1[3];
+  uint8_t received2[3];
+  uint8_t received3[3];
+  EXPECT_FALSE(cursor
+               .Read(received1, 3)
+               .Read(received2, 3)
+               .Read(received3, 3));
+  uint8_t expected1[3] = { 0x5d, 0x31, 0x09 };
+  uint8_t expected2[3] = { 0xa6, 0x2e, 0x2c };
+
+  EXPECT_TRUE(memcmp(received1, expected1, 3) == 0);
+  EXPECT_TRUE(memcmp(received2, expected2, 3) == 0);
+}
+
+TEST(Strings, PointTo) {
+  uint8_t data[] = { 0x83, 0x80, 0xb4, 0x38, 0x00, 0x2c, 0x0a, 0x27 };
+  ByteBuffer buffer(data, sizeof(data));
+  ByteCursor cursor(&buffer);
+
+  const uint8_t *received1;
+  const uint8_t *received2;
+  const uint8_t *received3;
+  const uint8_t *received4;
+  EXPECT_FALSE(cursor
+               .PointTo(&received1, 3)
+               .PointTo(&received2, 3)
+               .PointTo(&received3)
+               .PointTo(&received4, 3));
+  EXPECT_EQ(data + 0, received1);
+  EXPECT_EQ(data + 3, received2);
+  EXPECT_EQ(data + 6, received3);
+  EXPECT_EQ(NULL, received4);
+}
+
+TEST(Strings, CString) {
+  uint8_t data[] = "abc\0\0foo";
+  ByteBuffer buffer(data, sizeof(data) - 1);  // don't include terminating '\0'
+  ByteCursor cursor(&buffer);
+
+  string a, b, c;
+  EXPECT_TRUE(cursor.CString(&a).CString(&b));
+  EXPECT_EQ("abc", a);
+  EXPECT_EQ("", b);
+  EXPECT_FALSE(cursor.CString(&c));
+  EXPECT_EQ("", c);
+  EXPECT_TRUE(cursor.AtEnd());
+}
+
+TEST(Strings, CStringLimit) {
+  uint8_t data[] = "abcdef\0\0foobar";
+  ByteBuffer buffer(data, sizeof(data) - 1);  // don't include terminating '\0'
+  ByteCursor cursor(&buffer);
+
+  string a, b, c, d, e;
+
+  EXPECT_TRUE(cursor.CString(&a, 3));
+  EXPECT_EQ("abc", a);
+
+  EXPECT_TRUE(cursor.CString(&b, 0));
+  EXPECT_EQ("", b);
+
+  EXPECT_TRUE(cursor.CString(&c, 6));
+  EXPECT_EQ("def", c);
+
+  EXPECT_TRUE(cursor.CString(&d, 4));
+  EXPECT_EQ("ooba", d);
+
+  EXPECT_FALSE(cursor.CString(&e, 4));
+  EXPECT_EQ("", e);
+
+  EXPECT_TRUE(cursor.AtEnd());
+}
+
+//  uint8_t data[] = { 0xa6, 0x54, 0xdf, 0x67, 0x51, 0x43, 0xac, 0xf1 };
+//  ByteBuffer buffer(data, sizeof(data));
diff --git a/src/tools/linux/dump_syms/Makefile b/src/tools/linux/dump_syms/Makefile
index 3f8684d2..4d50c3aa 100644
--- a/src/tools/linux/dump_syms/Makefile
+++ b/src/tools/linux/dump_syms/Makefile
@@ -333,6 +333,25 @@ clean::
 
 
 
+### Unit tests for google_breakpad::ByteBuffer and google_breakpad::ByteCursor.
+check: check-byte_cursor_unittest
+check-byte_cursor_unittest: byte_cursor_unittest
+byte_cursor_unittest:				\
+	gmock-all.o				\
+	gtest-all.o				\
+	gtest_main.o				\
+	$(empty)
+CPP_EXECUTABLES += byte_cursor_unittest
+VPATH += $(SRC)/common
+byte_cursor_unittest.o: byte_cursor_unittest.cc
+byte_cursor_unittest.o: override CPPFLAGS += $(GTEST_CPPFLAGS) \
+					     $(GMOCK_CPPFLAGS)
+COVERAGE_SOURCES += byte_cursor_unittest.cc
+clean::
+	rm -f byte_cursor_unittest
+
+
+
 ### Generic compilation rules.
 
 # Link C++ executables using the C++ compiler; see CPP_EXECUTABLES above.