diff --git a/src/libs.rs b/src/libs.rs
new file mode 100644
index 0000000..f914ac5
--- /dev/null
+++ b/src/libs.rs
@@ -0,0 +1,71 @@
+use chrono::prelude::*;
+use chrono::{Duration, TimeZone};
+use nom::bytes::complete::tag;
+use nom::number::complete::{u24, u8};
+use nom::number::Endianness::Little;
+use nom::sequence::{preceded, tuple};
+use nom::IResult;
+
+struct IS {
+    total_length: usize,
+    version_number: u8,
+}
+fn isParser(input: &[u8]) -> IResult<&[u8], IS> {
+    let grib = tag([]);
+    let total_length = u24(Little);
+    let editon = u8;
+
+    let (input, (len, edition_number)) = preceded(grib, tuple((total_length, editon)))(input)?;
+
+    Ok((
+        input,
+        IS {
+            total_length: len as usize,
+            version_number: edition_number,
+        },
+    ))
+}
+
+struct PDS {
+    length: usize,
+    center_identification: Center,
+    generating_process_id: u8,
+    grid_identification: GridID,
+    pub gds: bool,
+    pub bms: bool,
+    units: u8,
+    level_type_and_value: String,
+    datetime: DateTime<Utc>,
+    forecast_time_unit: Duration,
+    time_range: usize,
+    average_number: u16,
+    missing_number: u8,
+    decimal_scale: u16,
+}
+
+enum Center {
+    WMC(u8),
+    RSMC(u8),
+    RAFC(u8),
+    INPE(u8),
+    NMC(u8),
+    NCAR(u8),
+    Other(u8),
+}
+
+enum GridID {
+    Lambert,
+    Mocator,
+}
+
+fn pdsParser(input: &[u8]) -> IResult<&[u8], IS> {
+    let length = u24(Little);
+}
+
+struct GDS {
+    length: usize,
+    nv: u8,
+    pv_or_pl: u8,
+    r_type: u8,
+    description: u8,
+}