From 187e6bab242ddc839af2e3a99a40272249d26527 Mon Sep 17 00:00:00 2001
From: Zachary Hall <catmeow72@proton.me>
Date: Tue, 15 Oct 2024 13:01:07 -0700
Subject: [PATCH] Prefer previous position used when loop position is not
 exactly at a command

---
 backends/playback/zsm/zsm_backend.cpp | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/backends/playback/zsm/zsm_backend.cpp b/backends/playback/zsm/zsm_backend.cpp
index 3fd16c4..a1ab804 100644
--- a/backends/playback/zsm/zsm_backend.cpp
+++ b/backends/playback/zsm/zsm_backend.cpp
@@ -49,23 +49,33 @@ void ZsmBackend::load(const char *filename) {
     pcm_data_offs = (loop_point[0] * 16) + pcm_offset;
     file->seek(music_data_start, SeekType::SET);
     this->loop_point = std::max(this->loop_point, (uint32_t)music_data_start);
+    double prev_time = 0.0;
     double time = 0.0;
     double tmpDelayTicks = 0.0;
     loop_pos = -1.0;
+    uint32_t prev_pos = music_data_start;
     while (true) {
         tmpDelayTicks -= get_delay_per_frame();
         if (tmpDelayTicks < 0.0) {
-            if (file->get_pos() >= this->loop_point && this->loop_pos < 0) {
-            	loop_pos = time;
-            	this->loop_point = file->get_pos();
-            }
             ZsmCommand cmd = get_command();
+            size_t cur_pos = file->get_pos();
+            if (cur_pos >= this->loop_point && this->loop_pos < 0) {
+            	if (cur_pos > this->loop_point) {
+             		this->loop_point = prev_pos;
+               		loop_pos = prev_time;
+	            } else {
+	               	loop_pos = time;
+	               	this->loop_point = cur_pos;
+	            }
+            }
             if (cmd.id == ZsmEOF) {
                 break;
             } else if (cmd.id == Delay) {
                 time += ((double)cmd.delay) / ((double)(tick_rate));
                 tmpDelayTicks += cmd.delay;
             }
+            prev_pos = file->get_pos();
+            prev_time = time;
         }
     }
     if (this->loop_pos < 0.0) {