taler-rust

commit 9fd9f8217e102c24ca980ec92f689403a64f3c2a
parent 77e9bb891753ecc6ef06660b7a339c9e07675ff4
Author: Antoine A <>
Date:   Sat, 11 Jan 2025 16:39:27 +0100

common: optimize subject parsing

Diffstat:
M
common/taler-api/src/subject.rs
 | 
40
++++++++++++----------------------------

1 file changed, 12 insertions(+), 28 deletions(-)
diff --git a/common/taler-api/src/subject.rs b/common/taler-api/src/subject.rs
@@ -163,27 +163,13 @@ pub fn parse_incoming_unstructured(subject: &str) -> Option<IncomingSubjectResul
 
     // Find and concatenate valid parts of a keys
     let (parts, concatenated) = {
-        let mut parts = Vec::new();
-        let mut concatenated = String::new();
-        let mut part = None;
-        for (i, b) in subject.as_bytes().iter().enumerate() {
-            if b.is_ascii_alphanumeric() {
-                if part.is_none() {
-                    part = Some(i);
-                }
-            } else if let Some(from) = part {
-                let start = concatenated.len() as u16;
-                concatenated.push_str(&subject[from..i]);
-                let end = concatenated.len() as u16;
-                parts.push(start..end);
-                part = None;
-            }
-        }
-        if let Some(from) = part {
-            let start = concatenated.len() as u16;
-            concatenated.push_str(&subject[from..]);
-            let end = concatenated.len() as u16;
-            parts.push(start..end);
+        let mut parts = Vec::with_capacity(4);
+        let mut concatenated = String::with_capacity(subject.len().min(KYC_SIZE + 10));
+        parts.push(0u16);
+        for part in subject.as_bytes().split(|b| !b.is_ascii_alphanumeric()) {
+            // SAFETY: part are all valid ASCII alphanumeric
+            concatenated.push_str(unsafe { std::str::from_utf8_unchecked(part) });
+            parts.push(concatenated.len() as u16);
         }
         (parts, concatenated)
     };
@@ -191,19 +177,17 @@ pub fn parse_incoming_unstructured(subject: &str) -> Option<IncomingSubjectResul
     // Find best candidates
     let mut best: Option<Candidate> = None;
     // For each part as a starting point
-    for (i, start) in parts.iter().enumerate() {
+    for (i, &start) in parts.iter().enumerate() {
         // Use progressively longer concatenation
-        for end in parts[i..].iter() {
-            let range = start.start..end.end;
+        for &end in &parts[i..] {
             // Until they are to long to be a key
-            if range.len() > KYC_SIZE {
+            if (end - start) as usize > KYC_SIZE {
                 break;
-            }
+            };
 
             // Parse the concatenated parts
             // SAFETY: we now end.end <= concatenated.len
-            let slice =
-                unsafe { &concatenated.get_unchecked(start.start as usize..end.end as usize) };
+            let slice = unsafe { &concatenated.get_unchecked(start as usize..end as usize) };
             if let Some(other) = parse_single(slice) {
                 // On success update best candidate
                 match &mut best {