From 634add9d10a9460fd1c33c8b0e49a96bc99f76fa Mon Sep 17 00:00:00 2001
From: Kai Zhao <zhaokaijia@gmail.com>
Date: Tue, 10 Dec 2024 08:49:38 -0500
Subject: [PATCH] update logic for dispatcher

---
 include/SZ3/api/impl/SZDispatcher.hpp | 34 ++++++++++++---------------
 1 file changed, 15 insertions(+), 19 deletions(-)

diff --git a/include/SZ3/api/impl/SZDispatcher.hpp b/include/SZ3/api/impl/SZDispatcher.hpp
index 87b4d1ff..4b52fbc4 100644
--- a/include/SZ3/api/impl/SZDispatcher.hpp
+++ b/include/SZ3/api/impl/SZDispatcher.hpp
@@ -51,26 +51,22 @@ size_t SZ_compress_dispatcher(Config &conf, const T *data, uchar *cmpData, size_
     if (conf.cmprAlgo == ALGO_LOSSLESS || !isCmpCapSufficient) {
         conf.cmprAlgo = ALGO_LOSSLESS;
         auto zstd = Lossless_zstd();
-        cmpSize = zstd.compress(reinterpret_cast<const uchar *>(data), conf.num * sizeof(T), cmpData, cmpCap);
-    } else {
-        // if lossy compression ratio < 3, test if lossless only mode has a better ratio than lossy
-        if (conf.num * sizeof(T) / 1.0 / cmpSize < 3) {
-            auto zstd = Lossless_zstd();
-            auto zstdCmpCap = ZSTD_compressBound(conf.num * sizeof(T));
-            auto zstdCmpData = static_cast<uchar *>(malloc(cmpCap));
-            size_t zstdCmpSize =
-                zstd.compress(reinterpret_cast<const uchar *>(data), conf.num * sizeof(T), zstdCmpData, zstdCmpCap);
-            if (zstdCmpSize < cmpSize) {
-                conf.cmprAlgo = ALGO_LOSSLESS;
-                if (zstdCmpSize > cmpCap) {
-                    fprintf(stderr, "%s\n", SZ_ERROR_COMP_BUFFER_NOT_LARGE_ENOUGH);
-                    throw std::length_error(SZ_ERROR_COMP_BUFFER_NOT_LARGE_ENOUGH);
-                }
-                memcpy(cmpData, zstdCmpData, zstdCmpSize);
-                cmpSize = zstdCmpSize;
-            }
-            free(zstdCmpData);
+        return zstd.compress(reinterpret_cast<const uchar *>(data), conf.num * sizeof(T), cmpData, cmpCap);
+    }
+    
+    // if lossy compression ratio < 3, test if lossless only mode has a better ratio than lossy
+    if (conf.num * sizeof(T) / 1.0 / cmpSize < 3) {
+        auto zstd = Lossless_zstd();
+        auto zstdCmpCap = ZSTD_compressBound(conf.num * sizeof(T));
+        auto zstdCmpData = static_cast<uchar *>(malloc(zstdCmpCap));
+        size_t zstdCmpSize =
+            zstd.compress(reinterpret_cast<const uchar *>(data), conf.num * sizeof(T), zstdCmpData, zstdCmpCap);
+        if (zstdCmpSize < cmpSize && zstdCmpSize <= cmpCap) {
+            conf.cmprAlgo = ALGO_LOSSLESS;
+            memcpy(cmpData, zstdCmpData, zstdCmpSize);
+            cmpSize = zstdCmpSize;
         }
+        free(zstdCmpData);
     }
     return cmpSize;
 }