[wpiutil] Remove STLExtras.h

This is a very inefficient header, and it's good to remove to discourage
its use.  Only a handful of use cases remained, and of only array_lengthof.

cscore/src/main/native/cpp/CvSourceImpl.cpp

@@ -7,7 +7,6 @@
 #include <opencv2/core/core.hpp>
 #include <opencv2/highgui/highgui.hpp>
 #include <opencv2/imgproc/imgproc.hpp>
-#include <wpi/STLExtras.h>
 #include <wpi/timestamp.h>
 
 #include "Handle.h"

cscore/src/main/native/linux/UsbCameraImpl.cpp

@@ -41,6 +41,14 @@
 
 using namespace cs;
 
+namespace {
+// Find the length of an array.
+template <class T, size_t N>
+constexpr inline size_t array_lengthof(T (&)[N]) {
+  return N;
+}
+}  // namespace
+
 static constexpr char const* kPropWbAuto = "white_balance_temperature_auto";
 static constexpr char const* kPropWbValue = "white_balance_temperature";
 static constexpr char const* kPropExAuto = "exposure_auto";
@@ -124,7 +132,7 @@ int UsbCameraImpl::RawToPercentage(const UsbCameraProperty& rawProp,
   // LifeCam exposure setting quirk
   if (m_lifecam_exposure && rawProp.name == "raw_exposure_absolute" &&
       rawProp.minimum == 5 && rawProp.maximum == 20000) {
-    int nelems = wpi::array_lengthof(quirkLifeCamHd3000);
+    int nelems = array_lengthof(quirkLifeCamHd3000);
     for (int i = 0; i < nelems; ++i) {
       if (rawValue < quirkLifeCamHd3000[i]) {
         return 100.0 * i / nelems;
@@ -141,7 +149,7 @@ int UsbCameraImpl::PercentageToRaw(const UsbCameraProperty& rawProp,
   // LifeCam exposure setting quirk
   if (m_lifecam_exposure && rawProp.name == "raw_exposure_absolute" &&
       rawProp.minimum == 5 && rawProp.maximum == 20000) {
-    int nelems = wpi::array_lengthof(quirkLifeCamHd3000);
+    int nelems = array_lengthof(quirkLifeCamHd3000);
     int ndx = nelems * percentValue / 100.0;
     if (ndx < 0) {
       ndx = 0;

cscore/src/main/native/linux/UsbCameraImpl.h

@@ -15,7 +15,6 @@
 #include <utility>
 #include <vector>
 
-#include <wpi/STLExtras.h>
 #include <wpi/SmallVector.h>
 #include <wpi/condition_variable.h>
 #include <wpi/mutex.h>

cscore/src/main/native/windows/UsbCameraImpl.h

@@ -22,7 +22,6 @@
 #include <vector>
 
 #include <Dbt.h>
-#include <wpi/STLExtras.h>
 #include <wpi/SmallVector.h>
 #include <wpi/condition_variable.h>
 #include <wpi/mutex.h>

wpiutil/src/main/native/cpp/HttpUtil.cpp

@@ -8,7 +8,6 @@
 
 #include "fmt/format.h"
 #include "wpi/Base64.h"
-#include "wpi/STLExtras.h"
 #include "wpi/StringExtras.h"
 #include "wpi/TCPConnector.h"
 #include "wpi/raw_ostream.h"

wpiutil/src/main/native/cpp/llvm/raw_ostream.cpp

@@ -16,7 +16,6 @@
 #endif
 
 #include "wpi/raw_ostream.h"
-#include "wpi/STLExtras.h"
 #include "wpi/SmallString.h"
 #include "wpi/SmallVector.h"
 #include "wpi/StringExtras.h"
@@ -65,6 +64,14 @@
 
 using namespace wpi;
 
+namespace {
+// Find the length of an array.
+template <class T, std::size_t N>
+constexpr inline size_t array_lengthof(T (&)[N]) {
+  return N;
+}
+}  // namespace
+
 raw_ostream::~raw_ostream() {
   // raw_ostream's subclasses should take care to flush the buffer
   // in their destructors.