query: add count param

crates/brk_query/src/params.rs

@@ -23,8 +23,11 @@ pub struct Params {
     pub from: Option<i64>,
     #[clap(short, long, allow_hyphen_values = true)]
     #[serde(default, alias = "t")]
-    /// Inclusive ending index, if negative will be from the end
+    /// Exclusive ending index, if negative will be from the end, overrides 'count'
     pub to: Option<i64>,
+    #[serde(default, alias = "c")]
+    /// Number of values
+    pub count: Option<usize>,
     #[clap(short = 'F', long)]
     /// Format of the output
     pub format: Option<Format>,

crates/brk_server/src/api/query/mod.rs

@@ -40,13 +40,27 @@ fn req_to_response_res(
         format,
         from,
         index,
-        to,
+        mut to,
+        count,
         values,
     }): AxumQuery<Params>,
     AppState { query, .. }: AppState,
 ) -> color_eyre::Result<Response> {
     let index = Index::try_from(index.as_str())?;
 
+    if to.is_none() {
+        if let Some(c) = count {
+            let c = c as i64;
+            if let Some(f) = from {
+                if f.is_positive() || f.abs() > c {
+                    to.replace(f + c);
+                }
+            } else {
+                to.replace(c);
+            }
+        }
+    }
+
     let vecs = query.search(
         index,
         &values.iter().map(|v| v.as_str()).collect::<Vec<_>>(),

crates/brk_vec/src/traits/collectable.rs

@@ -27,7 +27,7 @@ where
     #[inline]
     fn i64_to_usize(i: i64, len: usize) -> usize {
         if i >= 0 {
-            i as usize
+            (i as usize).min(len)
         } else {
             let v = len as i64 + i;
             if v < 0 { 0 } else { v as usize }