feat(read_header): add core_file read header

Author: chyyran

chd-rs-capi/chd.h

@@ -166,6 +166,31 @@ chd_error chd_codec_config(const struct chd_file *_chd, int32_t _param, void *_c
 chd_error chd_read_header(const char *filename,
                           struct chd_header *header);
 
+/**
+ * Read CHD header data from the file into the pointed struct.
+ *
+ * Ownership of the core_file is retained by the caller when calling this function.
+ *
+ * # Safety
+ * * `filename` is a valid, null-terminated **UTF-8** string.
+ * * `header` is either `NULL`, or an aligned pointer to a possibly uninitialized `chd_header` struct.
+ * * If `header` is `NULL`, returns `CHDERR_INVALID_PARAMETER`
+ */
+chd_error chd_read_header_file(core_file *file,
+                               struct chd_header *header);
+
+/**
+ * Read CHD header data from the file into the pointed struct.
+ *
+ * Ownership is retained by the caller when calling this function.
+ *
+ * # Safety
+ * * `file` is a valid pointer to a `core_file` with respect to the implementation of libchdcorefile that was linked.
+ * * `header` is either `NULL`, or an aligned pointer to a possibly uninitialized `chd_header` struct.
+ */
+chd_error chd_read_header_core_file(core_file *file,
+                                    struct chd_header *header);
+
 /**
  * Returns the associated `core_file*`.
  *

chd-rs-capi/src/lib.rs

@@ -358,6 +358,63 @@ pub unsafe extern "C" fn chd_read_header(
     }
 }
 
+#[no_mangle]
+#[cfg(feature = "chd_core_file")]
+#[cfg_attr(docsrs, doc(cfg(chd_core_file)))]
+/// Read CHD header data from the file into the pointed struct.
+///
+/// Ownership of the core_file is retained by the caller when calling this function.
+///
+/// # Safety
+/// * `filename` is a valid, null-terminated **UTF-8** string.
+/// * `header` is either `NULL`, or an aligned pointer to a possibly uninitialized `chd_header` struct.
+/// * If `header` is `NULL`, returns `CHDERR_INVALID_PARAMETER`
+pub unsafe extern "C" fn chd_read_header_file(
+    file: *mut chdcorefile_sys::core_file,
+    header: *mut MaybeUninit<chd_header>,
+) -> chd_error {
+    let core_file = Box::new(crate::chdcorefile::CoreFile { file }) as Box<dyn SeekRead>;
+    let chd = match Chd::open(core_file, None) {
+        Ok(chd) => chd,
+        Err(e) => return e,
+    };
+
+    let result = match chd {
+        Ok(chd) => {
+            let chd_header = ffi_chd_get_header(&chd);
+            match unsafe { header.as_mut() } {
+                None => Error::InvalidParameter,
+                Some(header) => {
+                    header.write(chd_header);
+                    Error::None
+                }
+            }
+        }
+        Err(e) => e,
+    };
+
+    let (_file, _) = chd.into_inner();
+
+    result
+}
+
+#[no_mangle]
+#[cfg(feature = "chd_virtio")]
+#[cfg_attr(docsrs, doc(cfg(chd_virtio)))]
+/// Read CHD header data from the file into the pointed struct.
+///
+/// Ownership is retained by the caller when calling this function.
+///
+/// # Safety
+/// * `file` is a valid pointer to a `core_file` with respect to the implementation of libchdcorefile that was linked.
+/// * `header` is either `NULL`, or an aligned pointer to a possibly uninitialized `chd_header` struct.
+pub unsafe extern "C" fn chd_read_header_core_file(
+    file: *mut chdcorefile_sys::core_file,
+    header: *mut MaybeUninit<chd_header>,
+) -> chd_error {
+    unsafe { chd_read_header_core_file(file, header) }
+}
+
 #[no_mangle]
 #[cfg(feature = "chd_core_file")]
 #[cfg_attr(docsrs, doc(cfg(chd_core_file)))]
@@ -431,7 +488,7 @@ pub unsafe extern "C" fn chd_open_file(
         Some(ffi_takeown_chd(parent))
     };
 
-    let core_file = Box::new(crate::chdcorefile::CoreFile { file: file }) as Box<dyn SeekRead>;
+    let core_file = Box::new(crate::chdcorefile::CoreFile { file }) as Box<dyn SeekRead>;
     let chd = match Chd::open(core_file, parent) {
         Ok(chd) => chd,
         Err(e) => return e,