Correctly write tags

It's now able to fix fake-utf8 v2.3 tags generated with the id3v2 tool!

1 files changed, 35 insertions, 2 deletions

diff --git a/src/encoding.rs b/src/encoding.rs
index fc0c335..9bc7290 100644
--- a/src/encoding.rs
+++ b/src/encoding.rs
@@ -1,7 +1,6 @@
 use std::convert::TryFrom;
-use std::io;
+use std::io::{self, Write};
 use crate::error::IntoIOError;
-use crate::util::read_big_endian;
 
 macro_rules! guard {
     ($cond:expr) => {
@@ -54,3 +53,37 @@ pub fn from_utf8_mistaken_as_latin1(latin1: &str) -> io::Result<String> {
                         .map(|s| s.to_string())
                         .map_err(|e| e.ioerr()))
 }
+
+pub fn read_big_endian(bytes: &[u8], bits: usize) -> usize {
+    if bits > 8 {
+        panic!("Invalid number of bits in encoding::read_big_endian()");
+    }
+
+    bytes
+        .iter()
+        .enumerate()
+        .map(|(i, &b)| (b as usize) << (bits * (bytes.len() - 1 - i)))
+        .sum()
+}
+
+pub fn write_big_endian<W: Write>(mut stream: W, mut value: usize, num_bytes: usize, bits: usize) -> io::Result<()> {
+    if num_bytes > 8 {
+        panic!("Invalid number of bytes in encoding::write_big_endian()");
+    }
+    if bits > 8 || bits == 0 {
+        panic!("Invalid number of bits in encoding::write_big_endian()");
+    }
+
+    let mask = (1 << bits) - 1;
+    let mut bytes = [0u8; 8];
+    for i in (0..num_bytes).rev() {
+        bytes[i] = (value & mask) as u8;
+        value >>= bits;
+    }
+
+    if value != 0 {
+        panic!("Value doesn't fit in encoding::write_big_endian()");
+    }
+
+    stream.write_all(&bytes[0..num_bytes])
+}