Increase chunk_size for faster password generation

src/pw

@@ -239,12 +239,15 @@ pw::gen() {
   local -i length=${1:-${PW_GEN_LENGTH}}
   local password="" class="${2:-"${PW_GEN_CLASS}"}"
 
+  local -i block_size=$(( length / 32 ))
+  (( block_size == 0 )) && block_size=1
+
   # Fix character classes for BusyBox tr
   [[ "${class}" == "[:graph:]" ]] && class="[:alnum:][:punct:]"
   [[ "${class}" == "[:print:]" ]] && class="[:alnum:][:punct:][:space:]"
 
   while (( "${#password}" != length )); do
-    password+=$(dd if=/dev/urandom bs=$(( length / 64 + 1 )) count=1 2>/dev/null | LC_CTYPE=C LC_ALL=C tr -dc "${class}" | head -c $(( length - ${#password} )))
+    password+=$(dd if=/dev/urandom bs=${block_size} count=1 2>/dev/null | LC_CTYPE=C LC_ALL=C tr -dc "${class}" | head -c $(( length - ${#password} )))
   done
   pw::output "${password}"
 }