dep/libchdr: Add read_header variants for user-provided file

dep/libchdr/include/libchdr/chd.h

@@ -398,6 +398,8 @@ CHD_EXPORT const char *chd_error_string(chd_error err);
 CHD_EXPORT const chd_header *chd_get_header(chd_file *chd);
 
 /* read CHD header data from file into the pointed struct */
+CHD_EXPORT chd_error chd_read_header_core_file(core_file *file, chd_header *header);
+CHD_EXPORT chd_error chd_read_header_file(FILE *file, chd_header *header);
 CHD_EXPORT chd_error chd_read_header(const char *filename, chd_header *header);
 
 

dep/libchdr/src/libchdr_chd.c

@@ -2009,34 +2009,44 @@ CHD_EXPORT const chd_header *chd_get_header(chd_file *chd)
     chd_read_header - read CHD header data
 	from file into the pointed struct
 -------------------------------------------------*/
-CHD_EXPORT chd_error chd_read_header(const char *filename, chd_header *header)
+CHD_EXPORT chd_error chd_read_header_core_file(core_file* file, chd_header* header)
 {
-	chd_error err = CHDERR_NONE;
 	chd_file chd;
-
-	/* punt if NULL */
-	if (filename == NULL || header == NULL)
-		EARLY_EXIT(err = CHDERR_INVALID_PARAMETER);
-
-	/* open the file */
-	chd.file = core_stdio_fopen(filename);
-	if (chd.file == NULL)
-		EARLY_EXIT(err = CHDERR_FILE_NOT_FOUND);
+	chd.file = file;
 
 	/* attempt to read the header */
-	err = header_read(&chd, header);
+	const chd_error err = header_read(&chd, header);
 	if (err != CHDERR_NONE)
-		EARLY_EXIT(err);
+		return err;
 
 	/* validate the header */
-	err = header_validate(header);
-	if (err != CHDERR_NONE)
-		EARLY_EXIT(err);
+	return header_validate(header);
+}
 
-cleanup:
-	if (chd.file != NULL)
-		core_fclose(chd.file);
+CHD_EXPORT chd_error chd_read_header_file(FILE *file, chd_header *header)
+{
+  core_file stream;
+  stream.argp = file;
+  stream.fsize = core_stdio_fsize;
+  stream.fread = core_stdio_fread;
+  stream.fclose = core_stdio_fclose_nonowner;
+  stream.fseek = core_stdio_fseek;
+
+	return chd_read_header_core_file(&stream, header);
+}
+
+CHD_EXPORT chd_error chd_read_header(const char *filename, chd_header *header)
+{
+	if (filename == NULL)
+		return CHDERR_INVALID_PARAMETER;
+
+	core_file* file = core_stdio_fopen(filename);
+	if (file == NULL)
+		return CHDERR_FILE_NOT_FOUND;
 
+	chd_error err = chd_read_header_core_file(file, header);
+	
+	core_fclose(file);
 	return err;
 }