geocode: implement US State & County FIPS code

partly implements #1352.

Now, we need to lookup FIPS code for US cities

src/cmd/geocode.rs

@@ -1532,25 +1532,25 @@ fn add_dyncols(
                 let admin1_code = cityrecord.admin_division.as_ref().map(|ad| ad.code.clone());
                 let us_state_code = match admin1_code {
                     Some(admin1_code) => {
-                        if admin1_code.starts_with("US.") {
+                        if let Some(state_fips_code) = admin1_code.strip_prefix("US.") {
                             // admin1 code is a US state code, the two-letter state code
                             // is the last two characters of the admin1 code
-                            admin1_code[3..].to_string()
+                            state_fips_code.to_string()
                         } else {
                             // admin1 code is not a US state code
                             // set to empty string
-                            "".to_string()
+                            String::new()
                         }
                     },
                     None => {
                         // no admin1 code
                         // set to empty string
-                        "".to_string()
+                        String::new()
                     },
                 };
                 // lookup US state FIPS code
                 let us_state_fips_code = lookup_fips_code(&us_state_code).unwrap_or_default();
-                record.push_field(&us_state_fips_code)
+                record.push_field(us_state_fips_code);
             },
             "us_county_fips_code" => {
                 let admin2_code = cityrecord
@@ -1564,20 +1564,20 @@ fn add_dyncols(
                             // is the last three characters of the admin2 code
                             // start at index 7 to skip the US. prefix
                             // e.g. US.NY.061 -> 061
-                            admin2_code[7..].to_string()
+                            format!("{:0>3}", admin2_code[7..].to_string())
                         } else {
                             // admin2 code is not a US county code
                             // set to empty string
-                            "".to_string()
+                            String::new()
                         }
                     },
                     None => {
                         // no admin2 code
                         // set to empty string
-                        "".to_string()
+                        String::new()
                     },
                 };
-                record.push_field(&us_county_fips_code)
+                record.push_field(&us_county_fips_code);
             },
 
             // CountryRecord fields
@@ -1700,39 +1700,55 @@ fn format_result(
         cityrecord_map.insert("population", cityrecord.population.to_string());
 
         // US FIPS fields
-        let admin1_code = cityrecord
-            .admin_division
-            .as_ref()
-            .map(|ad| ad.code.clone())
-            .unwrap_or_default();
-        let us_state_fips_code = lookup_fips_code(&admin1_code).unwrap_or_default();
+        // set US state FIPS code
+        let admin1_code = cityrecord.admin_division.as_ref().map(|ad| ad.code.clone());
+        let us_state_code = match admin1_code {
+            Some(admin1_code) => {
+                if let Some(state_fips_code) = admin1_code.strip_prefix("US.") {
+                    // admin1 code is a US state code, the two-letter state code
+                    // is the last two characters of the admin1 code
+                    state_fips_code.to_string()
+                } else {
+                    // admin1 code is not a US state code
+                    // set to empty string
+                    String::new()
+                }
+            },
+            None => {
+                // no admin1 code
+                // set to empty string
+                String::new()
+            },
+        };
+        let us_state_fips_code = lookup_fips_code(&us_state_code).unwrap_or_default();
         cityrecord_map.insert("us_state_fips_code", us_state_fips_code.to_string());
+
+        // set US county FIPS code
         cityrecord_map.insert("us_county_fips_code", {
             let admin2_code = cityrecord
                 .admin2_division
                 .as_ref()
                 .map(|ad| ad.code.clone());
-            let us_county_fips_code = match admin2_code {
+            match admin2_code {
                 Some(admin2_code) => {
                     if admin2_code.starts_with("US.") && admin2_code.len() == 9 {
                         // admin2 code is a US county code, the three-digit county code
                         // is the last three characters of the admin2 code
                         // start at index 7 to skip the US. prefix
                         // e.g. US.NY.061 -> 061
-                        admin2_code[7..].to_string()
+                        format!("{:0>3}", admin2_code[7..].to_string())
                     } else {
                         // admin2 code is not a US county code
                         // set to empty string
-                        "".to_string()
+                        String::new()
                     }
                 },
                 None => {
                     // no admin2 code
                     // set to empty string
-                    "".to_string()
+                    String::new()
                 },
-            };
-            us_county_fips_code
+            }
         });
 
         // countryrecord fields
@@ -1911,6 +1927,7 @@ fn get_cityrecord_name_in_lang(cityrecord: &CitiesRecord, lang_lookup: &str) ->
     }
 }
 
+#[inline]
 fn lookup_fips_code(state: &str) -> Option<&str> {
     US_STATES_FIPS_CODES_LOOKUP
         .iter()