Filter the entries directly without collecting twice

Signed-off-by: Constantin Nickel <constantin.nickel@gmail.com>

Cargo.toml

@@ -15,7 +15,7 @@ license       = "MIT"
 name="tar"
 
 [dependencies]
-nom = { default-features = false, features = ["alloc"], git = "https://github.com/Geal/nom.git", rev = "ef5e0bbc" }
+nom = { default-features = false, git = "https://github.com/Geal/nom.git", rev = "ef5e0bbc" }
 
 [badges]
 travis-ci = { repository = "Keruspe/tar-parser.rs" }

src/parser.rs

@@ -4,7 +4,7 @@ use nom::bytes::complete::{tag, take, take_until};
 use nom::character::complete::{oct_digit0, space0};
 use nom::combinator::{all_consuming, map, map_parser, map_res, opt};
 use nom::error::ErrorKind;
-use nom::multi::many0;
+use nom::multi::fold_many0;
 use nom::sequence::{pair, terminated};
 
 /*
@@ -375,13 +375,14 @@ fn parse_entry(i: &[u8]) -> IResult<&[u8], TarEntry<'_>> {
  * Tar archive parsing
  */
 
-fn filter_entries(entries: Vec<TarEntry<'_>>) -> Vec<TarEntry<'_>> {
-    /* Filter out empty entries */
-    entries.into_iter().filter(|e| !e.header.name.is_empty()).collect()
-}
-
 pub fn parse_tar(i: &[u8]) -> IResult<&[u8], Vec<TarEntry<'_>>> {
-    all_consuming(map(many0(parse_entry), filter_entries))(i)
+    let entries = fold_many0(parse_entry, Vec::new, |mut vec, e| {
+        if !e.header.name.is_empty() {
+            vec.push(e)
+        }
+        vec
+    });
+    all_consuming(entries)(i)
 }
 
 /*