Abstract the CRC lookup map

Author: rovo89

boards/XCORE/board_utils.cpp

@@ -1,6 +1,6 @@
 #include "board_utils.hpp"
 
-#include <etl/crc16_genibus.h>
+#include <crc_lookup_map.hpp>
 
 #pragma pack(push, 1)
 struct LineParams {
@@ -10,10 +10,6 @@ struct LineParams {
 };
 #pragma pack(pop)
 
-constexpr uint16_t crc16(const char* str) {
-  return etl::crc16_genibus(str, str + strlen(str)).value();
-}
-
 constexpr uint32_t ports[] = {GPIOA_BASE, GPIOB_BASE, GPIOC_BASE, GPIOD_BASE,
                               GPIOE_BASE, GPIOF_BASE, GPIOG_BASE, GPIOH_BASE};
 
@@ -123,28 +119,11 @@ constexpr LineParams lines[] = {
     {crc16("OSC_OUT"), port_idx('H'), 1},
 };
 
-static_assert(
-    [] {
-      constexpr size_t count = sizeof(lines) / sizeof(LineParams);
-      for (size_t i = 0; i < count; i++) {
-        for (size_t j = i + 1; j < count; j++) {
-          if (lines[i].crc == lines[j].crc) {
-            return false;
-          }
-        }
-      }
-      return true;
-    }(),
-    "CRC16 values are not unique");
+static_assert(HasUniqueCrcs(lines), "CRC16 values are not unique");
 
 ioline_t GetIoLineByName(const char* name) {
-  uint16_t crc = crc16(name);
-  for (const auto& line : lines) {
-    if (line.crc == crc) {
-      return PAL_LINE(ports[line.port], line.pad);
-    }
-  }
-  return PAL_NOLINE;
+  auto* line = LookupByName(name, lines);
+  return line != nullptr ? PAL_LINE(ports[line->port], line->pad) : PAL_NOLINE;
 }
 
 UARTDriver* GetUARTDriverByIndex(uint8_t index) {

src/crc_lookup_map.hpp

@@ -0,0 +1,36 @@
+#ifndef LOOKUP_HPP
+#define LOOKUP_HPP
+
+#include <etl/crc16_genibus.h>
+
+#include <cstdint>
+#include <cstring>
+
+constexpr uint16_t crc16(const char* str) {
+  return etl::crc16_genibus(str, str + strlen(str)).value();
+}
+
+template <typename T, size_t N>
+constexpr bool HasUniqueCrcs(const T (&arr)[N]) {
+  for (size_t i = 0; i < N; i++) {
+    for (size_t j = i + 1; j < N; j++) {
+      if (arr[i].crc == arr[j].crc) {
+        return false;
+      }
+    }
+  }
+  return true;
+}
+
+template <typename T, size_t N>
+const T* LookupByName(const char* name, const T (&arr)[N]) {
+  uint16_t crc = crc16(name);
+  for (const auto& item : arr) {
+    if (item.crc == crc) {
+      return &item;
+    }
+  }
+  return nullptr;
+}
+
+#endif  // LOOKUP_HPP

src/drivers/input/worx_input_driver.cpp

@@ -1,42 +1,51 @@
 #include "worx_input_driver.hpp"
 
 #include <etl/crc16_genibus.h>
-#include <etl/flat_map.h>
-#include <etl/string.h>
 #include <ulog.h>
 
+#include <crc_lookup_map.hpp>
 #include <json_stream.hpp>
 
 #define IS_BIT_SET(x, bit) ((x & (1 << bit)) != 0)
 
 namespace xbot::driver::input {
 
-static const etl::flat_map<etl::string<13>, uint8_t, 8> INPUT_BITS = {
+#pragma pack(push, 1)
+namespace {
+struct InputParams {
+  uint16_t crc;
+  uint8_t bit;
+};
+}  // namespace
+#pragma pack(pop)
+
+static constexpr InputParams available_inputs[] = {
     // Keys
-    {"start", 1},
-    {"home", 2},
-    {"back", 3},
+    {crc16("start"), 1},
+    {crc16("home"), 2},
+    {crc16("back"), 3},
 
     // Halls
-    {"battery_cover", 9},
-    {"stop1", 10},
-    {"trapped1", 12},
-    {"trapped2", 13},
-    {"stop2", 15},
+    {crc16("battery_cover"), 9},
+    {crc16("stop1"), 10},
+    {crc16("trapped1"), 12},
+    {crc16("trapped2"), 13},
+    {crc16("stop2"), 15},
 };
 
+static_assert(HasUniqueCrcs(available_inputs), "CRC16 values are not unique");
+
 bool WorxInputDriver::OnInputConfigValue(lwjson_stream_parser_t* jsp, const char* key, lwjson_stream_type_t type,
                                          Input& input) {
   if (strcmp(key, "id") == 0) {
     JsonExpectType(STRING);
-    decltype(INPUT_BITS)::key_type input_id{jsp->data.str.buff};
-    auto bit_it = INPUT_BITS.find(input_id);
-    if (bit_it == INPUT_BITS.end()) {
-      ULOG_ERROR("Unknown Worx input ID \"%s\"", input_id.c_str());
-      return false;
+    const auto* id = jsp->data.str.buff;
+    if (auto* params = LookupByName(id, available_inputs)) {
+      input.worx.bit = params->bit;
+      return true;
     }
-    input.worx.bit = bit_it->second;
-    return true;
+    ULOG_ERROR("Unknown ID \"%s\"", id);
+    return false;
   }
   ULOG_ERROR("Unknown attribute \"%s\"", key);
   return false;