From 61bccb9dccdee21b6c9af794eded885a5b59a954 Mon Sep 17 00:00:00 2001
From: Damien Collard <damien.collard@laposte.net>
Date: Sun, 10 Feb 2019 22:37:43 +0100
Subject: [PATCH 1/3] Avoid allocating a key at each conversion to lowercase.

---
 src/env.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/env.rs b/src/env.rs
index ce670695..6111e4a5 100644
--- a/src/env.rs
+++ b/src/env.rs
@@ -78,7 +78,7 @@ impl Source for Environment {
 
         // Define a prefix pattern to test and exclude from keys
         let prefix_pattern = match self.prefix {
-            Some(ref prefix) => Some(prefix.clone() + "_"),
+            Some(ref prefix) => Some((prefix.clone() + "_").to_lowercase()),
             _ => None,
         };
 
@@ -94,7 +94,7 @@ impl Source for Environment {
             if let Some(ref prefix_pattern) = prefix_pattern {
                 if key
                     .to_lowercase()
-                    .starts_with(&prefix_pattern.to_lowercase())
+                    .starts_with(prefix_pattern)
                 {
                     // Remove this prefix from the key
                     key = key[prefix_pattern.len()..].to_string();

From 8ad1ec1994f127eef7faf8049fa76af0f921d16e Mon Sep 17 00:00:00 2001
From: Damien Collard <damien.collard@laposte.net>
Date: Sun, 10 Feb 2019 22:38:51 +0100
Subject: [PATCH 2/3] Avoid converting twice to lowercase.

---
 src/env.rs | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/src/env.rs b/src/env.rs
index 6111e4a5..fbf12f44 100644
--- a/src/env.rs
+++ b/src/env.rs
@@ -88,14 +88,11 @@ impl Source for Environment {
                 continue;
             }
 
-            let mut key = key.to_string();
+            let mut key = key.to_lowercase();
 
             // Check for prefix
             if let Some(ref prefix_pattern) = prefix_pattern {
-                if key
-                    .to_lowercase()
-                    .starts_with(prefix_pattern)
-                {
+                if key.starts_with(prefix_pattern) {
                     // Remove this prefix from the key
                     key = key[prefix_pattern.len()..].to_string();
                 } else {
@@ -110,7 +107,7 @@ impl Source for Environment {
             }
 
             m.insert(
-                key.to_lowercase(),
+                key,
                 Value::new(Some(&uri), ValueKind::String(value)),
             );
         }

From ad43bb8b3f8ffc5b0a875cd5590c9ba426410442 Mon Sep 17 00:00:00 2001
From: Damien Collard <damien.collard@laposte.net>
Date: Sun, 10 Feb 2019 22:39:54 +0100
Subject: [PATCH 3/3] Simplify handling of separator in Source::collect().

---
 src/env.rs | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/src/env.rs b/src/env.rs
index fbf12f44..4e35c2b8 100644
--- a/src/env.rs
+++ b/src/env.rs
@@ -71,11 +71,6 @@ impl Source for Environment {
         let mut m = HashMap::new();
         let uri: String = "the environment".into();
 
-        let separator = match self.separator {
-            Some(ref separator) => separator,
-            _ => "",
-        };
-
         // Define a prefix pattern to test and exclude from keys
         let prefix_pattern = match self.prefix {
             Some(ref prefix) => Some((prefix.clone() + "_").to_lowercase()),
@@ -101,8 +96,7 @@ impl Source for Environment {
                 }
             }
 
-            // If separator is given replace with `.`
-            if !separator.is_empty() {
+            if let Some(ref separator) = self.separator {
                 key = key.replace(separator, ".");
             }