From 00e30bfcaab982c0f0a4193f13f280d035bfa151 Mon Sep 17 00:00:00 2001
From: Alex Shinn <ashinn@users.noreply.github.com>
Date: Tue, 22 Jun 2010 22:58:26 +0900
Subject: [PATCH] packing string data into symbol instead of consing an extra
 string object

---
 include/chibi/sexp.h | 5 +++--
 sexp.c               | 6 +++---
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/include/chibi/sexp.h b/include/chibi/sexp.h
index 69684c3b..a9c642e5 100644
--- a/include/chibi/sexp.h
+++ b/include/chibi/sexp.h
@@ -206,7 +206,8 @@ struct sexp_struct {
       char data[];
     } string;
     struct {
-      sexp string;
+      sexp_uint_t length;
+      char data[];
     } symbol;
     struct {
       FILE *stream;
@@ -569,7 +570,7 @@ SEXP_API sexp sexp_make_unsigned_integer(sexp ctx, sexp_luint_t x);
 #define sexp_string_ref(x, i) (sexp_make_character((unsigned char)sexp_string_data(x)[sexp_unbox_fixnum(i)]))
 #define sexp_string_set(x, i, v) (sexp_string_data(x)[sexp_unbox_fixnum(i)] = sexp_unbox_character(v))
 
-#define sexp_symbol_string(x)  ((x)->value.symbol.string)
+#define sexp_symbol_string(x)  (x)
 
 #define sexp_port_stream(p)    ((p)->value.port.stream)
 #define sexp_port_name(p)      ((p)->value.port.name)
diff --git a/sexp.c b/sexp.c
index 75333dab..075553a1 100644
--- a/sexp.c
+++ b/sexp.c
@@ -87,7 +87,7 @@ static struct sexp_struct _sexp_type_specs[] = {
   _DEF_TYPE(SEXP_CHAR, 0, 0, 0, 0, 0, 0, 0, 0, "char", NULL),
   _DEF_TYPE(SEXP_BOOLEAN, 0, 0, 0, 0, 0, 0, 0, 0, "boolean", NULL),
   _DEF_TYPE(SEXP_PAIR, sexp_offsetof(pair, car), 2, 3, 0, 0, sexp_sizeof(pair), 0, 0, "pair", NULL),
-  _DEF_TYPE(SEXP_SYMBOL, sexp_offsetof(symbol, string), 1, 1, 0, 0, sexp_sizeof(symbol), 0, 0, "symbol", NULL),
+  _DEF_TYPE(SEXP_SYMBOL, 0, 0, 0, 0, 0, sexp_sizeof(symbol)+1, sexp_offsetof(symbol, length), 1, "symbol", NULL),
   _DEF_TYPE(SEXP_STRING, 0, 0, 0, 0, 0, sexp_sizeof(string)+1, sexp_offsetof(string, length), 1, "string", NULL),
   _DEF_TYPE(SEXP_VECTOR, sexp_offsetof(vector, data), 0, 0, sexp_offsetof(vector, length), 1, sexp_sizeof(vector), sexp_offsetof(vector, length), sizeof(sexp), "vector", NULL),
   _DEF_TYPE(SEXP_FLONUM, 0, 0, 0, 0, 0, sexp_sizeof(flonum), 0, 0, "real", NULL),
@@ -790,9 +790,9 @@ sexp sexp_intern(sexp ctx, const char *str, sexp_sint_t len) {
 
   /* not found, make a new symbol */
   sexp_gc_preserve1(ctx, sym);
-  sym = sexp_alloc_type(ctx, symbol, SEXP_SYMBOL);
+  sym = sexp_c_string(ctx, str, len);
   if (sexp_exceptionp(sym)) return sym;
-  sexp_symbol_string(sym) = sexp_c_string(ctx, str, len);
+  sexp_pointer_tag(sym) = SEXP_SYMBOL;
   sexp_push(ctx, sexp_context_symbols(ctx)[bucket], sym);
   sexp_gc_release1(ctx);
   return sym;