Avoid rounding 99.995% matches up to 100.00% in the function diff view (#427)

* Avoid rounding 99.995% matches up to 100% in the function diff view

* Fix objdiff-wasm build

Author: LagoLunatic

objdiff-cli/src/views/function_diff.rs

@@ -10,6 +10,7 @@ use objdiff_core::{
         display::{DiffText, DiffTextColor, HighlightKind, display_row},
     },
     obj::Object,
+    util::format_percent,
 };
 use ratatui::{
     Frame,
@@ -88,7 +89,7 @@ impl UiView for FunctionDiffUi {
             .and_then(|(_, _, d)| d.match_percent)
         {
             line_r.spans.push(Span::styled(
-                format!("{percent:.2}% "),
+                format!("{} ", format_percent(percent)),
                 Style::new().fg(match_percent_color(percent)),
             ));
         }

objdiff-core/src/util.rs

@@ -1,4 +1,4 @@
-use alloc::{format, vec::Vec};
+use alloc::{format, string::String, vec::Vec};
 use core::fmt;
 
 use anyhow::{Result, ensure};
@@ -26,6 +26,15 @@ impl<N: PrimInt> fmt::UpperHex for ReallySigned<N> {
     }
 }
 
+/// Formats a progress percentage as a string, and prevents partial matches from being rounded to 0.00% or 100.00%.
+pub fn format_percent(value: f32) -> String {
+    let mut value = value;
+    if value > 0.0 && value < 100.0 {
+        value = value.clamp(0.01, 99.99);
+    }
+    format!("{value:.2}%")
+}
+
 pub fn read_u32(obj_file: &object::File, reader: &mut &[u8]) -> Result<u32> {
     ensure!(reader.len() >= 4, "Not enough bytes to read u32");
     let value = reader[..4].try_into()?;

objdiff-gui/src/views/diff.rs

@@ -12,7 +12,7 @@ use objdiff_core::{
         },
     },
     obj::{InstructionArgValue, Object, Symbol},
-    util::ReallySigned,
+    util::{ReallySigned, format_percent},
 };
 use time::format_description;
 
@@ -535,7 +535,7 @@ pub fn diff_view_ui(
                     let mut needs_separator = false;
                     if let Some(match_percent) = symbol_diff.match_percent {
                         let response = ui.label(
-                            RichText::new(format!("{match_percent:.2}%"))
+                            RichText::new(format_percent(match_percent))
                                 .font(appearance.code_font.clone())
                                 .color(match_color_for_symbol(match_percent, appearance)),
                         );