str: New function ds_steal_cstr.

[pspp-builds.git] / src / libpspp / str.c

diff --git a/src/libpspp/str.c b/src/libpspp/str.c
index afe32de9f2049bfcc5a80ac7a95b36b348be4cb7..79f3c912e9b649cf39d3ab9a0b37510e25867bf5 100644 (file)
--- a/src/libpspp/str.c
+++ b/src/libpspp/str.c
@@ -23,6 +23,7 @@
 #include <stdint.h>
 #include <stdlib.h>
 
+#include <libpspp/cast.h>
 #include <libpspp/message.h>
 #include <libpspp/pool.h>
 
@@ -1214,13 +1215,24 @@ ds_capacity (const struct string *st)
 char *
 ds_cstr (const struct string *st_)
 {
-  struct string *st = (struct string *) st_;
+  struct string *st = CONST_CAST (struct string *, st_);
   if (st->ss.string == NULL)
     ds_extend (st, 1);
   st->ss.string[st->ss.length] = '\0';
   return st->ss.string;
 }
 
+/* Returns the value of ST as a null-terminated string and then
+   reinitialized ST as an empty string.  The caller must free the
+   returned string with free(). */
+char *
+ds_steal_cstr (struct string *st)
+{
+  char *s = ds_cstr (st);
+  ds_init_empty (st);
+  return s;
+}
+
 /* Reads characters from STREAM and appends them to ST, stopping
    after MAX_LENGTH characters, after appending a newline, or
    after an I/O error or end of file was encountered, whichever