From c0b48dedf98adb7a518089638d4cc28fe1d2c4ac Mon Sep 17 00:00:00 2001
From: Andrew Duffy <andreweduffy@gmail.com>
Date: Wed, 21 Aug 2024 10:50:46 -0400
Subject: [PATCH] add single bytes as candidates

---
 src/builder.rs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/builder.rs b/src/builder.rs
index cc58190..84243df 100644
--- a/src/builder.rs
+++ b/src/builder.rs
@@ -252,6 +252,14 @@ impl Compressor {
             counter.record_count1(code);
             counter.record_count2(prev_code, code);
 
+            // Record the first byte of `code` as its own symbol so that it is a candidate for merging
+            // with `prev_code`. This allows us to grow the symbol table by one byte rather than
+            // concatenating a full symbol.
+            if code >= 256 {
+                let first_byte = self.symbols[code as usize].first_byte();
+                counter.record_count2(prev_code, first_byte as u16);
+            }
+
             prev_code = code;
         }
     }