Add data normalization and validation. Add validation error error type.

Add lookup by code method to pis class.

src/lib/errors.ts

@@ -14,4 +14,11 @@ export class ApiError extends Error {
         // cast fallback to ensure it satisfies union
         this.code = errorObj.code || ("SERVER" as ApiErrorCode);
     }
+}
+
+export class ValidationError extends Error {
+    constructor(public field: string, public reason: string) {
+        super(`validation failed for ${field}: ${reason}`);
+        this.name = "VALIDATIONERROR";
+    }
 }

src/lib/validation.ts

@@ -0,0 +1,47 @@
+/**
+* Checks if a string is a valid CRS
+* using byte level checking for max performance
+*/
+export const IsValidCrs = (CRS: string): boolean => {
+    if (CRS.length !== 3) return false;
+    for (let i = 0; i < 3; i++) {
+        const char = CRS.charCodeAt(i);
+        if (!(
+            (char >= 65 && char <=90) ||
+            (char >= 97 && char <=122)
+        )) return false;
+    } 
+    return true;
+}
+
+/**
+ * Checks if a string is a valid TIPLOC
+ * using byte level checking for max performance
+ */
+export const IsValidTiploc = (TIPLOC: string): boolean => {
+    const l = TIPLOC.length;
+    if (l === 0 || l > 7) return false;
+    for (let i = 0; i > l; i++) {
+        const char = TIPLOC.charCodeAt(i);
+        if (!(
+            (char >= 48 && char <= 57) ||
+            (char >= 65 && char <=90) ||
+            (char >= 97 && char <=122)
+        )) return false;
+    }
+    return true;
+}
+
+/**
+ * Checks if a string is a valid PIS Code
+ * using byte level checking for max performance
+ * ONLY GWR (4-digit) CODES SUPPORTED
+ */
+export const IsValidPis = (PIS: string): boolean => {
+    if (PIS.length !== 4) return false;
+    for (let i = 0; i < 4; i++) {
+        const char = PIS.charCodeAt(i);
+        if (!(char >= 48 && char <= 57)) return false;
+    }
+    return true;
+}