io: constify dcm_filehandle_create_from_memory() buffer pointer

Author: bgilbert

include/dicom/dicom.h

@@ -2423,8 +2423,9 @@ DcmFilehandle *dcm_filehandle_create_from_file(DcmError **error,
  * :return: filehandle
  */
 DCM_EXTERN
-DcmFilehandle *dcm_filehandle_create_from_memory(DcmError **error, 
-                                                 char *buffer, int64_t length);
+DcmFilehandle *dcm_filehandle_create_from_memory(DcmError **error,
+                                                 const char *buffer,
+                                                 int64_t length);
 
 /**
  * Read File Metainformation from a File.

src/dicom-io.c

@@ -267,7 +267,7 @@ DcmFilehandle *dcm_filehandle_create_from_file(DcmError **error,
 
 
 typedef struct _DcmIOMemory {
-    char *buffer;
+    const char *buffer;
     int64_t length;
     int64_t read_point;
 } DcmIOMemory;
@@ -351,8 +351,9 @@ static int64_t dcm_io_seek_memory(DcmError **error, void *data,
 }
 
 
-DcmFilehandle *dcm_filehandle_create_from_memory(DcmError **error, 
-                                                 char *buffer, int64_t length)
+DcmFilehandle *dcm_filehandle_create_from_memory(DcmError **error,
+                                                 const char *buffer,
+                                                 int64_t length)
 {
     static DcmIO io = {
         dcm_io_open_memory,