Help/guide/tutorial: Adopt tutorial code

6 files changed, 176 insertions, 0 deletions

diff --git a/Help/guide/tutorial/Complete/MathFunctions/CMakeLists.txt b/Help/guide/tutorial/Complete/MathFunctions/CMakeLists.txt
new file mode 100644
index 0000000..161ad64
--- /dev/null
+++ b/Help/guide/tutorial/Complete/MathFunctions/CMakeLists.txt
@@ -0,0 +1,68 @@
+
+# add the library that runs
+add_library(MathFunctions MathFunctions.cxx)
+
+# state that anybody linking to us needs to include the current source dir
+# to find MathFunctions.h, while we don't.
+target_include_directories(MathFunctions
+                           INTERFACE
+                            $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
+                            $<INSTALL_INTERFACE:include>
+                           )
+
+# should we use our own math functions
+option(USE_MYMATH "Use tutorial provided math implementation" ON)
+if(USE_MYMATH)
+
+  # does this system provide the log and exp functions?
+  include(CheckSymbolExists)
+  set(CMAKE_REQUIRED_LIBRARIES "m")
+  check_symbol_exists(log "math.h" HAVE_LOG)
+  check_symbol_exists(exp "math.h" HAVE_EXP)
+
+  # first we add the executable that generates the table
+  add_executable(MakeTable MakeTable.cxx)
+
+  # add the command to generate the source code
+  add_custom_command(
+    OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/Table.h
+    COMMAND MakeTable ${CMAKE_CURRENT_BINARY_DIR}/Table.h
+    DEPENDS MakeTable
+    )
+
+  # library that just does sqrt
+  add_library(SqrtLibrary STATIC
+              mysqrt.cxx
+              ${CMAKE_CURRENT_BINARY_DIR}/Table.h
+              )
+
+  # state that we depend on our binary dir to find Table.h
+  target_include_directories(SqrtLibrary PRIVATE
+                             ${CMAKE_CURRENT_BINARY_DIR}
+                             )
+
+  set_target_properties(SqrtLibrary PROPERTIES
+                        POSITION_INDEPENDENT_CODE ${BUILD_SHARED_LIBS}
+                        )
+
+  target_compile_definitions(SqrtLibrary PRIVATE
+                             "$<$<BOOL:${HAVE_LOG}>:HAVE_LOG>"
+                             "$<$<BOOL:${HAVE_EXP}>:HAVE_EXP>"
+                             )
+  target_link_libraries(MathFunctions PRIVATE SqrtLibrary)
+endif()
+
+target_compile_definitions(MathFunctions PRIVATE "$<$<BOOL:${USE_MYMATH}>:USE_MYMATH>")
+
+# define the symbol stating we are using the declspec(dllexport) when
+# building on windows
+target_compile_definitions(MathFunctions PRIVATE "EXPORTING_MYMATH")
+
+# setup the version numbering
+set_property(TARGET MathFunctions PROPERTY VERSION "1.0.0")
+set_property(TARGET MathFunctions PROPERTY SOVERSION "1")
+
+install(TARGETS MathFunctions
+        DESTINATION lib
+        EXPORT MathFunctionsTargets)
+install(FILES MathFunctions.h DESTINATION include)
diff --git a/Help/guide/tutorial/Complete/MathFunctions/MakeTable.cxx b/Help/guide/tutorial/Complete/MathFunctions/MakeTable.cxx
new file mode 100644
index 0000000..ee58556
--- /dev/null
+++ b/Help/guide/tutorial/Complete/MathFunctions/MakeTable.cxx
@@ -0,0 +1,25 @@
+// A simple program that builds a sqrt table
+#include <cmath>
+#include <fstream>
+#include <iostream>
+
+int main(int argc, char* argv[])
+{
+  // make sure we have enough arguments
+  if (argc < 2) {
+    return 1;
+  }
+
+  std::ofstream fout(argv[1], std::ios_base::out);
+  const bool fileOpen = fout.is_open();
+  if (fileOpen) {
+    fout << "double sqrtTable[] = {" << std::endl;
+    for (int i = 0; i < 10; ++i) {
+      fout << sqrt(static_cast<double>(i)) << "," << std::endl;
+    }
+    // close the table with a zero
+    fout << "0};" << std::endl;
+    fout.close();
+  }
+  return fileOpen ? 0 : 1; // return 0 if wrote the file
+}
diff --git a/Help/guide/tutorial/Complete/MathFunctions/MathFunctions.cxx b/Help/guide/tutorial/Complete/MathFunctions/MathFunctions.cxx
new file mode 100644
index 0000000..5351184
--- /dev/null
+++ b/Help/guide/tutorial/Complete/MathFunctions/MathFunctions.cxx
@@ -0,0 +1,18 @@
+
+#include "MathFunctions.h"
+#include <cmath>
+
+#ifdef USE_MYMATH
+#  include "mysqrt.h"
+#endif
+
+namespace mathfunctions {
+double sqrt(double x)
+{
+#ifdef USE_MYMATH
+  return detail::mysqrt(x);
+#else
+  return std::sqrt(x);
+#endif
+}
+}
diff --git a/Help/guide/tutorial/Complete/MathFunctions/MathFunctions.h b/Help/guide/tutorial/Complete/MathFunctions/MathFunctions.h
new file mode 100644
index 0000000..3fb547b
--- /dev/null
+++ b/Help/guide/tutorial/Complete/MathFunctions/MathFunctions.h
@@ -0,0 +1,14 @@
+
+#if defined(_WIN32)
+#  if defined(EXPORTING_MYMATH)
+#    define DECLSPEC __declspec(dllexport)
+#  else
+#    define DECLSPEC __declspec(dllimport)
+#  endif
+#else // non windows
+#  define DECLSPEC
+#endif
+
+namespace mathfunctions {
+double DECLSPEC sqrt(double x);
+}
diff --git a/Help/guide/tutorial/Complete/MathFunctions/mysqrt.cxx b/Help/guide/tutorial/Complete/MathFunctions/mysqrt.cxx
new file mode 100644
index 0000000..96d9421
--- /dev/null
+++ b/Help/guide/tutorial/Complete/MathFunctions/mysqrt.cxx
@@ -0,0 +1,45 @@
+#include "MathFunctions.h"
+#include <iostream>
+
+// include the generated table
+#include "Table.h"
+
+#include <cmath>
+
+namespace mathfunctions {
+namespace detail {
+// a hack square root calculation using simple operations
+double mysqrt(double x)
+{
+  if (x <= 0) {
+    return 0;
+  }
+
+  // if we have both log and exp then use them
+#if defined(HAVE_LOG) && defined(HAVE_EXP)
+  double result = exp(log(x) * 0.5);
+  std::cout << "Computing sqrt of " << x << " to be " << result << " using log"
+            << std::endl;
+#else
+  // use the table to help find an initial value
+  double result = x;
+  if (x >= 1 && x < 10) {
+    result = sqrtTable[static_cast<int>(x)];
+  }
+
+  // if we have both log and exp then use them
+
+  // do ten iterations
+  for (int i = 0; i < 10; ++i) {
+    if (result <= 0) {
+      result = 0.1;
+    }
+    double delta = x - (result * result);
+    result = result + 0.5 * delta / result;
+    std::cout << "Computing sqrt of " << x << " to be " << result << std::endl;
+  }
+#endif
+  return result;
+}
+}
+}
diff --git a/Help/guide/tutorial/Complete/MathFunctions/mysqrt.h b/Help/guide/tutorial/Complete/MathFunctions/mysqrt.h
new file mode 100644
index 0000000..e1c42ef
--- /dev/null
+++ b/Help/guide/tutorial/Complete/MathFunctions/mysqrt.h
@@ -0,0 +1,6 @@
+
+namespace mathfunctions {
+namespace detail {
+double mysqrt(double x);
+}
+}