Replace std::snprintf() with wpi::format_to_n_c_str() (#5645)

fmtlib uses consteval format string processing, which makes it more
efficient than std::snprintf().

snprintf()s in libuv, mpack, processstarter, and wpigui were left alone.
processstarter uses stdlib only, and wpigui only depends on imgui.

fmt::format_to_n() is analogous to std::format_to_n()
(https://en.cppreference.com/w/cpp/utility/format/format_to_n)

wpi::format_to_n_c_str() is a wrapper which adds the trailing NUL.

glass/src/lib/native/cpp/Context.cpp

@@ -6,7 +6,6 @@
 
 #include <algorithm>
 #include <cinttypes>
-#include <cstdio>
 #include <filesystem>
 
 #include <fmt/format.h>
@@ -533,7 +532,8 @@ void glass::PushID(const char* str_id_begin, const char* str_id_end) {
 
 void glass::PushID(int int_id) {
   char buf[16];
-  std::snprintf(buf, sizeof(buf), "%d", int_id);
+  wpi::format_to_n_c_str(buf, sizeof(buf), "{}", int_id);
+
   PushStorageStack(buf);
   ImGui::PushID(int_id);
 }

glass/src/lib/native/cpp/MainMenuBar.cpp

@@ -4,9 +4,8 @@
 
 #include "glass/MainMenuBar.h"
 
-#include <cstdio>
-
 #include <imgui.h>
+#include <wpi/StringExtras.h>
 #include <wpigui.h>
 
 #include "glass/Context.h"
@@ -52,11 +51,11 @@ void MainMenuBar::Display() {
 
 #if 0
   char str[64];
-  std::snprintf(str, sizeof(str), "%.3f ms/frame (%.1f FPS)",
-                1000.0f / ImGui::GetIO().Framerate,
-                ImGui::GetIO().Framerate);
-  ImGui::SameLine(ImGui::GetWindowWidth() - ImGui::CalcTextSize(str).x -
-                  10);
+  wpi::format_to_n_c_str(str, sizeof(str), "{:.3f} ms/frame ({:.1f} FPS)",
+                         1000.0f / ImGui::GetIO().Framerate,
+                         ImGui::GetIO().Framerate);
+
+  ImGui::SameLine(ImGui::GetWindowWidth() - ImGui::CalcTextSize(str).x - 10);
   ImGui::Text("%s", str);
 #endif
   ImGui::EndMainMenuBar();

glass/src/lib/native/cpp/Window.cpp

@@ -56,9 +56,12 @@ void Window::Display() {
   }
 
   char label[128];
-  std::snprintf(label, sizeof(label), "%s###%s",
-                m_name.empty() ? m_defaultName.c_str() : m_name.c_str(),
-                m_id.c_str());
+  if (m_name.empty()) {
+    wpi::format_to_n_c_str(label, sizeof(label), "{}###{}", m_defaultName,
+                           m_id);
+  } else {
+    wpi::format_to_n_c_str(label, sizeof(label), "{}###{}", m_name, m_id);
+  }
 
   if (Begin(label, &m_visible, m_flags)) {
     if (m_renamePopupEnabled || m_view->HasSettings()) {

glass/src/lib/native/cpp/hardware/AnalogGyro.cpp

@@ -4,6 +4,8 @@
 
 #include "glass/hardware/AnalogGyro.h"
 
+#include <wpi/StringExtras.h>
+
 #include "glass/DataSource.h"
 #include "glass/other/DeviceTree.h"
 
@@ -11,7 +13,8 @@ using namespace glass;
 
 void glass::DisplayAnalogGyroDevice(AnalogGyroModel* model, int index) {
   char name[32];
-  std::snprintf(name, sizeof(name), "AnalogGyro[%d]", index);
+  wpi::format_to_n_c_str(name, sizeof(name), "AnalogGyro[{}]", index);
+
   if (BeginDevice(name)) {
     // angle
     if (auto angleData = model->GetAngleData()) {

glass/src/lib/native/cpp/hardware/AnalogInput.cpp

@@ -5,6 +5,7 @@
 #include "glass/hardware/AnalogInput.h"
 
 #include <imgui.h>
+#include <wpi/StringExtras.h>
 
 #include "glass/Context.h"
 #include "glass/DataSource.h"
@@ -22,9 +23,9 @@ void glass::DisplayAnalogInput(AnalogInputModel* model, int index) {
   std::string& name = GetStorage().GetString("name");
   char label[128];
   if (!name.empty()) {
-    std::snprintf(label, sizeof(label), "%s [%d]###name", name.c_str(), index);
+    wpi::format_to_n_c_str(label, sizeof(label), "{} [{}]###name", name, index);
   } else {
-    std::snprintf(label, sizeof(label), "In[%d]###name", index);
+    wpi::format_to_n_c_str(label, sizeof(label), "In[{}]###name", index);
   }
 
   if (model->IsGyro()) {

glass/src/lib/native/cpp/hardware/AnalogOutput.cpp

@@ -4,6 +4,8 @@
 
 #include "glass/hardware/AnalogOutput.h"
 
+#include <wpi/StringExtras.h>
+
 #include "glass/Context.h"
 #include "glass/DataSource.h"
 #include "glass/Storage.h"
@@ -30,9 +32,9 @@ void glass::DisplayAnalogOutputsDevice(AnalogOutputsModel* model) {
       std::string& name = GetStorage().GetString("name");
       char label[128];
       if (!name.empty()) {
-        std::snprintf(label, sizeof(label), "%s [%d]###name", name.c_str(), i);
+        wpi::format_to_n_c_str(label, sizeof(label), "{} [{}]###name", name, i);
       } else {
-        std::snprintf(label, sizeof(label), "Out[%d]###name", i);
+        wpi::format_to_n_c_str(label, sizeof(label), "Out[{}]###name", i);
       }
 
       double value = analogOutData->GetValue();

glass/src/lib/native/cpp/hardware/Encoder.cpp

@@ -6,6 +6,7 @@
 
 #include <fmt/format.h>
 #include <imgui.h>
+#include <wpi/StringExtras.h>
 
 #include "glass/Context.h"
 #include "glass/DataSource.h"
@@ -70,10 +71,11 @@ void glass::DisplayEncoder(EncoderModel* model) {
   std::string& name = GetStorage().GetString("name");
   char label[128];
   if (!name.empty()) {
-    std::snprintf(label, sizeof(label), "%s [%d,%d]###header", name.c_str(),
-                  chA, chB);
+    wpi::format_to_n_c_str(label, sizeof(label), "{} [{},{}]###header", name,
+                           chA, chB);
   } else {
-    std::snprintf(label, sizeof(label), "Encoder[%d,%d]###header", chA, chB);
+    wpi::format_to_n_c_str(label, sizeof(label), "Encoder[{},{}]###header", chA,
+                           chB);
   }
 
   // header

glass/src/lib/native/cpp/hardware/Gyro.cpp

@@ -5,12 +5,13 @@
 #include "glass/hardware/Gyro.h"
 
 #include <cmath>
+#include <numbers>
 
 #define IMGUI_DEFINE_MATH_OPERATORS
 
 #include <imgui.h>
 #include <imgui_internal.h>
-#include <numbers>
+#include <wpi/StringExtras.h>
 
 #include "glass/Context.h"
 #include "glass/DataSource.h"
@@ -65,7 +66,8 @@ void glass::DisplayGyro(GyroModel* m) {
                   color, 1.2f);
     if (major) {
       char txt[16];
-      std::snprintf(txt, sizeof(txt), "%d°", i);
+      wpi::format_to_n_c_str(txt, sizeof(txt), "{}°", i);
+
       draw->AddText(
           center + (direction * radius * 1.25) - ImGui::CalcTextSize(txt) * 0.5,
           primaryColor, txt, nullptr);

glass/src/lib/native/cpp/hardware/PCM.cpp

@@ -9,6 +9,7 @@
 
 #include <imgui.h>
 #include <wpi/SmallVector.h>
+#include <wpi/StringExtras.h>
 
 #include "glass/Context.h"
 #include "glass/DataSource.h"
@@ -46,10 +47,10 @@ bool glass::DisplayPCMSolenoids(PCMModel* model, int index,
   std::string& name = GetStorage().GetString("name");
   char label[128];
   if (!name.empty()) {
-    std::snprintf(label, sizeof(label), "%s [%d]###header", name.c_str(),
-                  index);
+    wpi::format_to_n_c_str(label, sizeof(label), "{} [{}]###header", name,
+                           index);
   } else {
-    std::snprintf(label, sizeof(label), "PCM[%d]###header", index);
+    wpi::format_to_n_c_str(label, sizeof(label), "PCM[{}]###header", index);
   }
 
   // header
@@ -111,7 +112,8 @@ void glass::DisplayCompressorDevice(PCMModel* model, int index,
 void glass::DisplayCompressorDevice(CompressorModel* model, int index,
                                     bool outputsEnabled) {
   char name[32];
-  std::snprintf(name, sizeof(name), "Compressor[%d]", index);
+  wpi::format_to_n_c_str(name, sizeof(name), "Compressor[{}]", index);
+
   if (BeginDevice(name)) {
     // output enabled
     if (auto runningData = model->GetRunningData()) {

glass/src/lib/native/cpp/hardware/PWM.cpp

@@ -5,6 +5,7 @@
 #include "glass/hardware/PWM.h"
 
 #include <imgui.h>
+#include <wpi/StringExtras.h>
 
 #include "glass/Context.h"
 #include "glass/DataSource.h"
@@ -22,9 +23,9 @@ void glass::DisplayPWM(PWMModel* model, int index, bool outputsEnabled) {
   std::string& name = GetStorage().GetString("name");
   char label[128];
   if (!name.empty()) {
-    std::snprintf(label, sizeof(label), "%s [%d]###name", name.c_str(), index);
+    wpi::format_to_n_c_str(label, sizeof(label), "{} [{}]###name", name, index);
   } else {
-    std::snprintf(label, sizeof(label), "PWM[%d]###name", index);
+    wpi::format_to_n_c_str(label, sizeof(label), "PWM[{}]###name", index);
   }
 
   int led = model->GetAddressableLED();

glass/src/lib/native/cpp/hardware/PowerDistribution.cpp

@@ -5,9 +5,9 @@
 #include "glass/hardware/PowerDistribution.h"
 
 #include <algorithm>
-#include <cstdio>
 
 #include <imgui.h>
+#include <wpi/StringExtras.h>
 
 #include "glass/Context.h"
 #include "glass/DataSource.h"
@@ -36,7 +36,8 @@ static float DisplayChannel(PowerDistributionModel& pdp, int channel) {
 
 void glass::DisplayPowerDistribution(PowerDistributionModel* model, int index) {
   char name[128];
-  std::snprintf(name, sizeof(name), "PowerDistribution[%d]", index);
+  wpi::format_to_n_c_str(name, sizeof(name), "PowerDistribution[{}]", index);
+
   if (CollapsingHeader(name)) {
     // temperature
     if (auto tempData = model->GetTemperatureData()) {

glass/src/lib/native/cpp/other/DeviceTree.cpp

@@ -7,6 +7,7 @@
 #include <cinttypes>
 
 #include <imgui.h>
+#include <wpi/StringExtras.h>
 
 #include "glass/Context.h"
 #include "glass/ContextInternal.h"
@@ -53,8 +54,11 @@ bool glass::BeginDevice(const char* id, ImGuiTreeNodeFlags flags) {
   // build label
   std::string& name = GetStorage().GetString("name");
   char label[128];
-  std::snprintf(label, sizeof(label), "%s###header",
-                name.empty() ? id : name.c_str());
+  if (name.empty()) {
+    wpi::format_to_n_c_str(label, sizeof(label), "{}###header", id);
+  } else {
+    wpi::format_to_n_c_str(label, sizeof(label), "{}###header", name);
+  }
 
   bool open = CollapsingHeader(label, flags);
   PopupEditName("header", &name);

glass/src/lib/native/cpp/other/Plot.cpp

@@ -8,7 +8,6 @@
 
 #include <algorithm>
 #include <atomic>
-#include <cstdio>
 #include <cstring>
 #include <memory>
 #include <string>
@@ -16,6 +15,7 @@
 #include <vector>
 
 #include <fmt/format.h>
+#include <wpi/StringExtras.h>
 
 #if defined(__GNUC__)
 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
@@ -321,8 +321,8 @@ PlotSeries::Action PlotSeries::EmitPlot(PlotView& view, double now, size_t i,
   CheckSource();
 
   char label[128];
-  std::snprintf(label, sizeof(label), "%s###name%d_%d", GetName(),
-                static_cast<int>(i), static_cast<int>(plotIndex));
+  wpi::format_to_n_c_str(label, sizeof(label), "{}###name{}_{}", GetName(),
+                         static_cast<int>(i), static_cast<int>(plotIndex));
 
   int size = m_size;
   int offset = m_offset;
@@ -580,8 +580,9 @@ void Plot::EmitPlot(PlotView& view, double now, bool paused, size_t i) {
   }
 
   char label[128];
-  std::snprintf(label, sizeof(label), "%s###plot%d", m_name.c_str(),
-                static_cast<int>(i));
+  wpi::format_to_n_c_str(label, sizeof(label), "{}###plot{}", m_name,
+                         static_cast<int>(i));
+
   ImPlotFlags plotFlags = (m_legend ? 0 : ImPlotFlags_NoLegend) |
                           (m_crosshairs ? ImPlotFlags_Crosshairs : 0) |
                           (m_mousePosition ? 0 : ImPlotFlags_NoMouseText);
@@ -937,14 +938,15 @@ void PlotView::Settings() {
 
     char name[64];
     if (!plot->GetName().empty()) {
-      std::snprintf(name, sizeof(name), "%s", plot->GetName().c_str());
+      wpi::format_to_n_c_str(name, sizeof(name), "{}", plot->GetName().c_str());
     } else {
-      std::snprintf(name, sizeof(name), "Plot %d", static_cast<int>(i));
+      wpi::format_to_n_c_str(name, sizeof(name), "Plot {}",
+                             static_cast<int>(i));
     }
 
     char label[90];
-    std::snprintf(label, sizeof(label), "%s###header%d", name,
-                  static_cast<int>(i));
+    wpi::format_to_n_c_str(label, sizeof(label), "{}###header{}", name,
+                           static_cast<int>(i));
 
     bool open = ImGui::CollapsingHeader(label);
 
@@ -1013,7 +1015,8 @@ void PlotProvider::DisplayMenu() {
     char id[32];
     size_t numWindows = m_windows.size();
     for (size_t i = 0; i <= numWindows; ++i) {
-      std::snprintf(id, sizeof(id), "Plot <%d>", static_cast<int>(i));
+      wpi::format_to_n_c_str(id, sizeof(id), "Plot <{}>", static_cast<int>(i));
+
       bool match = false;
       for (size_t j = 0; j < numWindows; ++j) {
         if (m_windows[j]->GetId() == id) {

glass/src/lib/native/cpp/support/NameSetting.cpp

@@ -4,9 +4,6 @@
 
 #include "glass/support/NameSetting.h"
 
-#include <cstdio>
-#include <cstring>
-
 #include <imgui_internal.h>
 #include <imgui_stdlib.h>
 #include <wpi/StringExtras.h>
@@ -16,75 +13,80 @@ using namespace glass;
 void NameSetting::GetName(char* buf, size_t size,
                           const char* defaultName) const {
   if (!m_name.empty()) {
-    std::snprintf(buf, size, "%s", m_name.c_str());
+    wpi::format_to_n_c_str(buf, size, "{}", m_name);
   } else {
-    std::snprintf(buf, size, "%s", defaultName);
+    wpi::format_to_n_c_str(buf, size, "{}", defaultName);
   }
 }
 
 void NameSetting::GetName(char* buf, size_t size, const char* defaultName,
                           int index) const {
   if (!m_name.empty()) {
-    std::snprintf(buf, size, "%s [%d]", m_name.c_str(), index);
+    wpi::format_to_n_c_str(buf, size, "{} [{}]", m_name, index);
   } else {
-    std::snprintf(buf, size, "%s[%d]", defaultName, index);
+    wpi::format_to_n_c_str(buf, size, "{}[{}]", defaultName, index);
   }
 }
 
 void NameSetting::GetName(char* buf, size_t size, const char* defaultName,
                           int index, int index2) const {
   if (!m_name.empty()) {
-    std::snprintf(buf, size, "%s [%d,%d]", m_name.c_str(), index, index2);
+    wpi::format_to_n_c_str(buf, size, "{} [{},{}]", m_name, index, index2);
   } else {
-    std::snprintf(buf, size, "%s[%d,%d]", defaultName, index, index2);
+    wpi::format_to_n_c_str(buf, size, "{}[{},{}]", defaultName, index, index2);
   }
 }
 
 void NameSetting::GetLabel(char* buf, size_t size,
                            const char* defaultName) const {
   if (!m_name.empty()) {
-    std::snprintf(buf, size, "%s###Name%s", m_name.c_str(), defaultName);
+    wpi::format_to_n_c_str(buf, size, "{}###Name{}", m_name, defaultName);
   } else {
-    std::snprintf(buf, size, "%s###Name%s", defaultName, defaultName);
+    wpi::format_to_n_c_str(buf, size, "{}###Name{}", defaultName, defaultName);
   }
 }
 
 void NameSetting::GetLabel(char* buf, size_t size, const char* defaultName,
                            int index) const {
   if (!m_name.empty()) {
-    std::snprintf(buf, size, "%s [%d]###Name%d", m_name.c_str(), index, index);
+    wpi::format_to_n_c_str(buf, size, "{} [{}]###Name{}", m_name, index, index);
   } else {
-    std::snprintf(buf, size, "%s[%d]###Name%d", defaultName, index, index);
+    wpi::format_to_n_c_str(buf, size, "{}[{}]###Name{}", defaultName, index,
+                           index);
   }
 }
 
 void NameSetting::GetLabel(char* buf, size_t size, const char* defaultName,
                            int index, int index2) const {
   if (!m_name.empty()) {
-    std::snprintf(buf, size, "%s [%d,%d]###Name%d", m_name.c_str(), index,
-                  index2, index);
+    wpi::format_to_n_c_str(buf, size, "{} [{},{}]###Name{}", m_name, index,
+                           index2, index);
   } else {
-    std::snprintf(buf, size, "%s[%d,%d]###Name%d", defaultName, index, index2,
-                  index);
+    wpi::format_to_n_c_str(buf, size, "{}[{},{}]###Name{}", defaultName, index,
+                           index2, index);
   }
 }
 
 void NameSetting::PushEditNameId(int index) {
   char id[64];
-  std::snprintf(id, sizeof(id), "Name%d", index);
+  wpi::format_to_n_c_str(id, sizeof(id), "Name{}", index);
+
   ImGui::PushID(id);
 }
 
 void NameSetting::PushEditNameId(const char* name) {
   char id[128];
-  std::snprintf(id, sizeof(id), "Name%s", name);
+  wpi::format_to_n_c_str(id, sizeof(id), "Name{}", name);
+
   ImGui::PushID(id);
 }
 
 bool NameSetting::PopupEditName(int index) {
   bool rv = false;
+
   char id[64];
-  std::snprintf(id, sizeof(id), "Name%d", index);
+  wpi::format_to_n_c_str(id, sizeof(id), "Name{}", index);
+
   if (ImGui::BeginPopupContextItem(id)) {
     ImGui::Text("Edit name:");
     if (InputTextName("##edit")) {
@@ -101,8 +103,10 @@ bool NameSetting::PopupEditName(int index) {
 
 bool NameSetting::PopupEditName(const char* name) {
   bool rv = false;
+
   char id[128];
-  std::snprintf(id, sizeof(id), "Name%s", name);
+  wpi::format_to_n_c_str(id, sizeof(id), "Name{}", name);
+
   if (ImGui::BeginPopupContextItem(id)) {
     ImGui::Text("Edit name:");
     if (InputTextName("##edit")) {