From 8421f2c03d6f905b58b5447a6e0469519c7f8fa6 Mon Sep 17 00:00:00 2001
From: tomsmeding <tom.smeding@gmail.com>
Date: Sun, 5 Jan 2020 20:44:27 +0100
Subject: Initial

---
 src/encoding.rs | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 src/encoding.rs

(limited to 'src/encoding.rs')

diff --git a/src/encoding.rs b/src/encoding.rs
new file mode 100644
index 0000000..a3851aa
--- /dev/null
+++ b/src/encoding.rs
@@ -0,0 +1,51 @@
+use std::convert::TryFrom;
+use crate::util::read_big_endian;
+
+macro_rules! guard {
+    ($cond:expr) => {
+        if !$cond {
+            return None;
+        }
+    }
+}
+
+pub fn from_latin_1(bytes: &[u8]) -> Option<String> {
+    guard!(bytes.len() >= 1);
+
+    Some(bytes.iter().map(|&b| char::from(b)).collect())
+}
+
+pub fn from_ucs_2_bom(bytes: &[u8]) -> Option<String> {
+    let len = bytes.len();
+
+    guard!(len % 2 == 0);
+    guard!(len >= 2);
+
+    let bom = read_big_endian(&bytes[0..2], 8);
+    guard!(bom == 0xfeff || bom == 0xfffe);
+
+    let mut res = String::with_capacity(len/2 - 1);
+
+    for i in 1 .. len/2 {
+        let val = if bom == 0xfeff {
+            256 * bytes[2*i] as u16 + bytes[2*i+1] as u16
+        } else {
+            256 * bytes[2*i+1] as u16 + bytes[2*i] as u16
+        };
+
+        match char::try_from(val as u32) {
+            Ok(c) => res.push(c),
+            Err(_) => return None,
+        };
+    }
+
+    Some(res)
+}
+
+// pub fn from_utf8_mistaken_as_latin1(latin1: &str) -> Option<String> {
+//     guard!(latin1.chars().all(|c| (c as usize) < 256));
+//     match std::str::from_utf8(latin1.as_bytes()) {
+//         Ok(res) => Some(res.to_string()),
+//         Err(_) => None,
+//     }
+// }
-- 
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