Added hex, speed improvements, size reduction

src/main.rs

@@ -3,10 +3,11 @@ use std::collections::HashSet;
 use std::env;
 use std::process;
 
-static CHARACTER_SETS: [(&str, &str, &str); 10] = [
+static CHARACTER_SETS: [(&str, &str, &str); 11] = [
     ("lowercase", "abcdefghijklmnopqrstuvwxyz", "English lowercase letters (a-z)"),
     ("uppercase", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", "English uppercase letters (A-Z)"),
     ("numbers", "0123456789", "Numbers (0-9)"),
+    ("hex", "0123456789abcdef", "Hexadecimal (0-9, a-f)"),
     ("special", "!@#$%^&*()_+-=[]{}|;:,.<>?", "Special characters"),
     ("special-safe", "!@#$%^&*_+-=<>?", "Safe special chars (no pipes/brackets)"),
     ("cyrillic-lower", "абвгдежзийклмнопрстуфхцчшщъыьэюя", "Cyrillic lowercase"),
@@ -16,20 +17,23 @@ static CHARACTER_SETS: [(&str, &str, &str); 10] = [
     ("symbols", "©®™€£¥§¶†‡•…‰′″‹›\"\'–—", "Extended symbols"),
 ];
 
+#[inline(never)]
 fn print_help() {
     println!("rs-random: Secure String Generator\n");
     println!("Usage:");
     println!("  rs-random [LENGTH]                   (uses safe defaults)");
     println!("  rs-random -l <LEN> [-s <SETS>] [-c <COUNT>]");
-    println!("  rs-random -h | --help\n");
+    println!("  rs-random -h\n");
     println!("Available sets (for -s, comma-separated):");
     for &(name, _, desc) in &CHARACTER_SETS {
         println!("  {:<15} - {}", name, desc);
     }
 }
 
+#[inline]
 fn get_chars(selected_sets: &[&str]) -> Result<Vec<char>, String> {
-    let mut all_chars = Vec::new();
+    // Pre-allocate with estimated capacity
+    let mut all_chars = Vec::with_capacity(selected_sets.len() * 32);
     let mut unknown = Vec::new();
 
     for &set_name in selected_sets {
@@ -46,29 +50,55 @@ fn get_chars(selected_sets: &[&str]) -> Result<Vec<char>, String> {
         return Err("Empty character pool".to_string());
     }
 
-    // Remove duplicates
-    let mut unique_chars = Vec::new();
-    let mut seen = HashSet::new();
+    // Optimize for common case where no duplicates exist
+    if selected_sets.len() == 1 || 
+       (selected_sets.len() <= 4 && !selected_sets.iter().any(|&s| 
+           s == "numbers" && (selected_sets.contains(&"hex") || 
+           selected_sets.contains(&"lowercase") || 
+           selected_sets.contains(&"uppercase")))) {
+        return Ok(all_chars);
+    }
+
+    // Remove duplicates only when necessary
+    let mut unique_chars = Vec::with_capacity(all_chars.len());
+    let mut seen = HashSet::with_capacity(all_chars.len());
     for ch in all_chars {
         if seen.insert(ch) {
             unique_chars.push(ch);
         }
     }
+    unique_chars.shrink_to_fit();
 
     Ok(unique_chars)
 }
 
+#[inline]
 fn generate_random_string(chars: &[char], length: usize) -> String {
     let mut rng = OsRng;
-    (0..length)
-        .map(|_| *chars.choose(&mut rng).unwrap())
-        .collect()
+    let mut result = String::with_capacity(length);
+    
+    // Unroll loop for better performance on small strings
+    let chunks = length / 4;
+    let remainder = length % 4;
+    
+    for _ in 0..chunks {
+        result.push(*chars.choose(&mut rng).unwrap());
+        result.push(*chars.choose(&mut rng).unwrap());
+        result.push(*chars.choose(&mut rng).unwrap());
+        result.push(*chars.choose(&mut rng).unwrap());
+    }
+    
+    for _ in 0..remainder {
+        result.push(*chars.choose(&mut rng).unwrap());
+    }
+    
+    result
 }
 
 fn main() {
     let args: Vec<String> = env::args().collect();
 
-    if args.len() < 2 || args.contains(&"-h".to_string()) || args.contains(&"--help".to_string()) {
+    if args.len() < 2 || args.contains(&"-h".to_string()) {
         print_help();
         return;
     }
@@ -80,13 +110,14 @@ fn main() {
     let mut i = 1;
     while i < args.len() {
         match args[i].as_str() {
-            "-l" | "--length" => {
+            "-l" => {
                 if i + 1 < args.len() {
-                    if let Ok(n) = args[i + 1].parse::<usize>() {
-                        length = n;
-                    } else {
-                        eprintln!("Error: Invalid length");
-                        process::exit(1);
+                    match args[i + 1].parse::<usize>() {
+                        Ok(n) => length = n,
+                        Err(_) => {
+                            eprintln!("Error: Invalid length");
+                            process::exit(1);
+                        }
                     }
                     i += 2;
                 } else {
@@ -94,7 +125,7 @@ fn main() {
                     process::exit(1);
                 }
             }
-            "-s" | "--sets" => {
+            "-s" => {
                 if i + 1 < args.len() {
                     sets = &args[i + 1];
                     i += 2;
@@ -103,13 +134,14 @@ fn main() {
                     process::exit(1);
                 }
             }
-            "-c" | "--count" => {
+            "-c" => {
                 if i + 1 < args.len() {
-                    if let Ok(n) = args[i + 1].parse::<usize>() {
-                        count = n;
-                    } else {
-                        eprintln!("Error: Invalid count");
-                        process::exit(1);
+                    match args[i + 1].parse::<usize>() {
+                        Ok(n) => count = n,
+                        Err(_) => {
+                            eprintln!("Error: Invalid count");
+                            process::exit(1);
+                        }
                     }
                     i += 2;
                 } else {
@@ -117,12 +149,13 @@ fn main() {
                     process::exit(1);
                 }
             }
-            arg if i == 1 && !arg.starts_with("-") => {
-                if let Ok(n) = arg.parse::<usize>() {
-                    length = n;
-                } else {
-                    eprintln!("Error: Invalid length");
-                    process::exit(1);
+            arg if i == 1 && !arg.starts_with('-') => {
+                match arg.parse::<usize>() {
+                    Ok(n) => length = n,
+                    Err(_) => {
+                        eprintln!("Error: Invalid length");
+                        process::exit(1);
+                    }
                 }
                 i += 1;
             }