From de232d2a33b711524d4af9ce7747d86b19bc10e1 Mon Sep 17 00:00:00 2001
From: CDrummond <craig.p.drummond@gmail.com>
Date: Mon, 19 May 2025 12:07:28 +0100
Subject: [PATCH] Use max of 16 significant digits (traling zeros stripped)
 when writing analysis results to file tags.

Issue #26
---
 ChangeLog   |  2 ++
 src/tags.rs | 14 +++++++++-----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 7a65012..d64c2c7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -8,6 +8,8 @@
    list to DB.
 6. Multi-thread DB export.
 7. Add --read-tags and --write-tags commandline options.
+8. Use max of 16 significant digits (traling zeros stripped) when writing
+   analysis results to file tags.
 
 0.3.0
 -----
diff --git a/src/tags.rs b/src/tags.rs
index 1eeafe8..3a0dfa6 100644
--- a/src/tags.rs
+++ b/src/tags.rs
@@ -24,12 +24,16 @@ const NUM_ANALYSIS_VALS: usize = 20;
 const ANALYSIS_TAG: &str = "BLISS_ANALYSIS";
 const ANALYSIS_TAG_FORMAT_VER: u16 = 1;
 
+fn fmt(val: f32) -> String {
+    format!("{:.16}", val).trim_end_matches("0").to_string()
+}
+
 pub fn write_analysis(track: &String, analysis: &Analysis, preserve_mod_times: bool) -> bool {
-    let value = format!("{},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24},{:.24}", ANALYSIS_TAG_FORMAT_VER,
-                        analysis[AnalysisIndex::Tempo], analysis[AnalysisIndex::Zcr], analysis[AnalysisIndex::MeanSpectralCentroid], analysis[AnalysisIndex::StdDeviationSpectralCentroid], analysis[AnalysisIndex::MeanSpectralRolloff],
-                        analysis[AnalysisIndex::StdDeviationSpectralRolloff], analysis[AnalysisIndex::MeanSpectralFlatness], analysis[AnalysisIndex::StdDeviationSpectralFlatness], analysis[AnalysisIndex::MeanLoudness], analysis[AnalysisIndex::StdDeviationLoudness],
-                        analysis[AnalysisIndex::Chroma1], analysis[AnalysisIndex::Chroma2], analysis[AnalysisIndex::Chroma3], analysis[AnalysisIndex::Chroma4], analysis[AnalysisIndex::Chroma5],
-                        analysis[AnalysisIndex::Chroma6], analysis[AnalysisIndex::Chroma7], analysis[AnalysisIndex::Chroma8], analysis[AnalysisIndex::Chroma9], analysis[AnalysisIndex::Chroma10]);
+    let value = format!("{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{}", ANALYSIS_TAG_FORMAT_VER,
+                        fmt(analysis[AnalysisIndex::Tempo]), fmt(analysis[AnalysisIndex::Zcr]), fmt(analysis[AnalysisIndex::MeanSpectralCentroid]), fmt(analysis[AnalysisIndex::StdDeviationSpectralCentroid]), fmt(analysis[AnalysisIndex::MeanSpectralRolloff]),
+                        fmt(analysis[AnalysisIndex::StdDeviationSpectralRolloff]), fmt(analysis[AnalysisIndex::MeanSpectralFlatness]), fmt(analysis[AnalysisIndex::StdDeviationSpectralFlatness]), fmt(analysis[AnalysisIndex::MeanLoudness]), fmt(analysis[AnalysisIndex::StdDeviationLoudness]),
+                        fmt(analysis[AnalysisIndex::Chroma1]), fmt(analysis[AnalysisIndex::Chroma2]), fmt(analysis[AnalysisIndex::Chroma3]), fmt(analysis[AnalysisIndex::Chroma4]), fmt(analysis[AnalysisIndex::Chroma5]),
+                        fmt(analysis[AnalysisIndex::Chroma6]), fmt(analysis[AnalysisIndex::Chroma7]), fmt(analysis[AnalysisIndex::Chroma8]), fmt(analysis[AnalysisIndex::Chroma9]), fmt(analysis[AnalysisIndex::Chroma10]));
 
     let mut written = false;
     if let Ok(mut file) = lofty::read_from_path(Path::new(track)) {