There is a pretty common pattern in the code for testing for internal

errors of the form

  if(some_expr_indicating_failure)
     throw Internal_Error("Some mildly informative message");

Make this simpiler with the addition of a BOTAN_ASSERT macro which will
throw an exception upon failure.

3 files changed, 86 insertions, 0 deletions

diff --git a/src/utils/assert.cpp b/src/utils/assert.cpp
new file mode 100644
index 000000000..29af831d8
--- /dev/null
+++ b/src/utils/assert.cpp
@@ -0,0 +1,35 @@
+/*
+* Runtime assertion checking
+* (C) 2010 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/internal/assert.h>
+#include <botan/exceptn.h>
+#include <sstream>
+
+namespace Botan {
+
+void assertion_failure(const char* expr_str,
+                       const char* msg,
+                       const char* func,
+                       const char* file,
+                       int line)
+   {
+   std::ostringstream format;
+
+   format << "Assertion " << expr_str << " failed ";
+
+   if(msg)
+      format << "(" << msg << ") ";
+
+   if(func)
+      format << "in " << func << " ";
+
+   format << "@" << file << ":" << line;
+
+   throw Internal_Error(format.str());
+   }
+
+}
diff --git a/src/utils/assert.h b/src/utils/assert.h
new file mode 100644
index 000000000..d84f5c7ad
--- /dev/null
+++ b/src/utils/assert.h
@@ -0,0 +1,49 @@
+/*
+* Runtime assertion checking
+* (C) 2010 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_ASSERTION_CHECKING_H__
+#define BOTAN_ASSERTION_CHECKING_H__
+
+namespace Botan {
+
+void assertion_failure(const char* expr_str,
+                       const char* msg,
+                       const char* func,
+                       const char* file,
+                       int line);
+
+#define BOTAN_ASSERT(expr, msg)                          \
+   do {                                                  \
+      if(!(expr))                                        \
+         Botan::assertion_failure(#expr,                 \
+                                  msg,                   \
+                                  BOTAN_ASSERT_FUNCTION, \
+                                  __FILE__,              \
+                                  __LINE__);             \
+   } while(0)
+
+/*
+* Unfortunately getting the function name from the preprocessor
+* isn't standard in C++98 (C++0x uses C99's __func__)
+*/
+#if defined(BOTAN_BUILD_COMPILER_IS_GCC) || \
+    defined(BOTAN_BUILD_COMPILER_IS_CLANG) || \
+    defined(BOTAN_BUILD_COMPILER_IS_INTEL)
+
+  #define BOTAN_ASSERT_FUNCTION __PRETTY_FUNCTION__
+
+#elif defined(BOTAN_BUILD_COMPILER_IS_MSVC)
+
+  #define BOTAN_ASSERT_FUNCTION __FUNCTION__
+
+#else
+  #define BOTAN_ASSERT_FUNCTION ((const char*)0)
+#endif
+
+}
+
+#endif
diff --git a/src/utils/info.txt b/src/utils/info.txt
index 2fb3e79a5..9d8e6173c 100644
--- a/src/utils/info.txt
+++ b/src/utils/info.txt
@@ -3,6 +3,7 @@ define UTIL_FUNCTIONS
 load_on always
 
 <source>
+assert.cpp
 charset.cpp
 cpuid.cpp
 mlock.cpp
@@ -13,6 +14,7 @@ version.cpp
 </source>
 
 <header:internal>
+assert.h
 bit_ops.h
 debug.h
 mlock.h