improve chunker speed (avoid modulo)

src/bin/test_chunk_speed.rs

@@ -6,29 +6,34 @@ fn main() {
 
     let mut buffer = Vec::new();
 
-    for i in 0..1024*1024 {
+    for i in 0..20*1024*1024 {
         for j in 0..4 {
             let byte = ((i >> (j<<3))&0xff) as u8;
             //println!("BYTE {}", byte);
             buffer.push(byte);
         }
     }
-    let mut chunker = Chunker::new(512*1024);
+    let mut chunker = Chunker::new(64*1024);
 
-    let count = 100;
+    let count = 5;
 
     let start = std::time::SystemTime::now();
+
+    let mut chunk_count = 0;
     
     for _i in 0..count {
         let mut pos = 0;
+        let mut last = 0;
         while pos < buffer.len() {
             let k = chunker.scan(&buffer[pos..]);
             if k == 0 {
                 //println!("LAST {}", pos);
                 break;
             } else {
+                last = pos;
                 pos += k;
-                //println!("CHUNK {}", pos);
+                chunk_count += 1;
+                //println!("CHUNK {} {}", pos, pos-last);
             }
         }
     }
@@ -38,6 +43,7 @@ fn main() {
         (elapsed.subsec_millis() as f64)/1000.0;
     
     let mbytecount = ((count*buffer.len()) as f64) / (1024.0*1024.0);
+    let avg_chunk_size = mbytecount/(chunk_count as f64);
     let mbytes_per_sec =  mbytecount/elapsed; 
-    println!("SPEED = {} MB/s", mbytes_per_sec); 
+    println!("SPEED = {} MB/s, avg chunk size = {} KB", mbytes_per_sec,  avg_chunk_size*1024.0);
 }