chore(code): split much of the efi support code to crates/eficore

crates/eficore/src/strings.rs

@@ -0,0 +1,22 @@
+use alloc::vec::Vec;
+use anyhow::{Context, Result, bail};
+use uefi::CString16;
+
+/// Convert a byte slice into a CString16.
+pub fn utf16_bytes_to_cstring16(bytes: &[u8]) -> Result<CString16> {
+    // Validate the input bytes are the right length.
+    if !bytes.len().is_multiple_of(2) {
+        bail!("utf16 bytes must be a multiple of 2");
+    }
+
+    // Convert the bytes to UTF-16 data.
+    let data = bytes
+        // Chunk everything into two bytes.
+        .chunks_exact(2)
+        // Reinterpret the bytes as u16 little-endian.
+        .map(|chunk| u16::from_le_bytes([chunk[0], chunk[1]]))
+        // Collect the result into a vector.
+        .collect::<Vec<_>>();
+
+    CString16::try_from(data).context("unable to convert utf16 bytes to CString16")
+}