simplify readFile, use std::array instead of c-style bufs

include/utils.hpp

@@ -1,6 +1,8 @@
 #ifndef UTILS_HPP
 #define UTILS_HPP
 
+#include <fcntl.h>
+#include <unistd.h>
 #include <array>
 #include <charconv>
 #include <cstdint>
@@ -10,27 +12,38 @@
 namespace utils {
 
 constexpr char fill_char = ' ';
+enum just { right, left };
 
-enum just { right,
-            left };
-
-std::string pad(std::string s, uint8_t len, just j = just::right);
+std::string pad(std::string s, uint8_t len, just j = right);
 std::string center(std::string str, uint8_t len);
 std::string pBytes(double bytes, bool isKbytes = false);
-ssize_t readFile(const std::string& path, char* buffer, size_t maxlen);
-ssize_t readFile(const char* path, char* buffer, size_t maxlen);
 std::string getFirstDir(const std::string_view& path);
 
+/* reads file into a std::array buffer */
+template <size_t N>
+inline ssize_t readFile(const std::string& path, std::array<char, N>& buffer) {
+    const int fd = open(path.c_str(), O_RDONLY | O_CLOEXEC);
+    if (fd < 0) {
+        applog(LOG::ERR, "Error reading {}", path);
+        return 0;
+    }
+    const ssize_t len = read(fd, buffer.data(), buffer.size());
+    if (len >= 0) buffer[len] = '\0';
+    close(fd);
+    return len;
+}
+
+
 /* reads a number fast and divides it if needed */
 template <uint32_t Divider = 1, typename T, size_t N>
-inline void fastReadNum(const std::string& path, char (&buf)[N], T& result) {
-    readFile(path, buf, N);
+inline void fastReadNum(const std::string& path, std::array<char, N>& buf, T& result) {
+    readFile(path, buf);
     if constexpr (Divider == 1) {
-        std::from_chars(buf, buf + N, result);
+        std::from_chars(buf.data(), buf.data() + N, result);
         return;
     }
     uint64_t temp{};
-    std::from_chars(buf, buf + N, temp);
+    std::from_chars(buf.data(), buf.data() + N, temp);
     if constexpr (std::is_floating_point_v<T>)
         result = temp / static_cast<T>(Divider);
     else