Use bc in backround for multiple bc's running much faster

Use bc in backround for multiple bc's running much faster

gaboshlib/g_calc.sh

@@ -1,3 +1,34 @@
 function g_calc {
- echo "scale=8; $@" | bc | sed 's/^\./0./; s/^-\./-0./'
-}
+
+  # Use bc in backround for multiple bc's running much faster
+  if [ -z "${g_bc_running}" ]
+  then
+    [ -p ${g_tmp}/bc-in ] || mkfifo ${g_tmp}/bc-in
+    [ -p ${g_tmp}/bc-out ] || mkfifo ${g_tmp}/bc-out
+    [ -p ${g_tmp}/bc-sed-in ] || mkfifo ${g_tmp}/bc-sed-in
+    [ -p ${g_tmp}/bc-sed-out ] || mkfifo ${g_tmp}/bc-sed-out
+    
+    # bc stream channel
+    bc -ql <${g_tmp}/bc-in >${g_tmp}/bc-out &
+    exec 3>${g_tmp}/bc-in 4<${g_tmp}/bc-out
+    
+    # sed stream channel
+    sed -su 's/^\./0./; s/^-\./-0./' <${g_tmp}/bc-sed-in >${g_tmp}/bc-sed-out &
+    exec 5>${g_tmp}/bc-sed-in 6<${g_tmp}/bc-sed-out
+    
+    g_bc_running="true"
+  fi 2>/dev/null
+  
+  # do bc
+  echo "scale=8; $@" >&3
+  local g_bc_out
+  read g_bc_out <&4
+  
+  # do sed
+  echo ${g_bc_out} >&5
+  local g_sed_out
+  read g_sed_out <&6
+  
+  # echo result
+  echo ${g_sed_out}
+}