diff options
| author | Andy Wingo <wingo@pobox.com> | 2017-02-17 11:29:31 +0100 |
|---|---|---|
| committer | Andy Wingo <wingo@pobox.com> | 2017-02-17 11:29:31 +0100 |
| commit | 9ee21f3e97ae65b79a861d076e3ea8f73508bda8 (patch) | |
| tree | 556c718871541bbcec54e7773eff2efd22088fbc /libguile | |
| parent | 2864f11d3415c650d9e80f8e7787e4df81dcc7e9 (diff) | |
Minor make-string optimization
* libguile/strings.c (STRINGBUF_SET_MUTABLE): New helper.
(scm_i_string_ensure_mutable_x): Use new helper.
(scm_make_string): Mark stringbuf as mutable.
Diffstat (limited to 'libguile')
| -rw-r--r-- | libguile/strings.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/libguile/strings.c b/libguile/strings.c index e460a938d..8d0aa453f 100644 --- a/libguile/strings.c +++ b/libguile/strings.c @@ -83,6 +83,10 @@ SCM_SYMBOL (sym_error, "error"); #define STRINGBUF_WIDE(buf) (SCM_CELL_WORD_0(buf) & STRINGBUF_F_WIDE) #define STRINGBUF_MUTABLE(buf) (SCM_CELL_WORD_0(buf) & STRINGBUF_F_MUTABLE) + +#define STRINGBUF_SET_MUTABLE(buf) \ + SCM_SET_CELL_WORD_0 (buf, SCM_CELL_WORD_0 (buf) | STRINGBUF_F_MUTABLE) + #define STRINGBUF_CONTENTS(buf) ((void *) \ SCM_CELL_OBJECT_LOC (buf, \ STRINGBUF_HEADER_SIZE)) @@ -433,8 +437,7 @@ scm_i_string_ensure_mutable_x (SCM str) memcpy (STRINGBUF_CHARS (new_buf), STRINGBUF_CHARS (buf), len); } - SCM_SET_CELL_WORD_0 (new_buf, - SCM_CELL_WORD_0 (new_buf) | STRINGBUF_F_MUTABLE); + STRINGBUF_SET_MUTABLE (new_buf); SET_STRING_STRINGBUF (str, new_buf); } } @@ -1119,7 +1122,12 @@ SCM_DEFINE (scm_make_string, "make-string", 1, 1, 0, "of the string are all set to @code{#\nul}.") #define FUNC_NAME s_scm_make_string { - return scm_c_make_string (scm_to_size_t (k), chr); + SCM ret = scm_c_make_string (scm_to_size_t (k), chr); + /* Given that make-string is mostly used by Scheme to prepare a + mutable string buffer, let's go ahead and mark this as mutable to + avoid a copy when this buffer is next written to. */ + STRINGBUF_SET_MUTABLE (STRING_STRINGBUF (ret)); + return ret; } #undef FUNC_NAME |