--- JSON-XS/XS.xs	2007/06/25 04:08:17	1.44
+++ JSON-XS/XS.xs	2007/06/25 22:11:39	1.46
@@ -30,8 +30,11 @@
 #define F_CONV_BLESSED   0x00000800UL // NYI
 #define F_MAXDEPTH       0xf8000000UL
 #define S_MAXDEPTH       27
+#define F_MAXSIZE        0x01f00000UL
+#define S_MAXSIZE        20
 
 #define DEC_DEPTH(flags) (1UL << ((flags & F_MAXDEPTH) >> S_MAXDEPTH))
+#define DEC_SIZE(flags)  (1UL << ((flags & F_MAXSIZE ) >> S_MAXSIZE ))
 
 #define F_PRETTY    F_INDENT | F_SPACE_BEFORE | F_SPACE_AFTER
 #define F_DEFAULT   (9UL << S_MAXDEPTH)
@@ -1022,25 +1025,62 @@
   else
     for (;;)
       {
-        SV *key, *value;
-
         decode_ws (dec); EXPECT_CH ('"');
 
-        key = decode_str (dec);
-        if (!key)
-          goto fail;
+        // heuristic: assume that
+        // a) decode_str + hv_store_ent are abysmally slow
+        // b) most hash keys are short, simple ascii text
+        // so try to "fast-match" such strings to avoid
+        // the overhead of hv_store_ent.
+        {
+          SV *value;
+          char *p = dec->cur;
+          char *e = p + 24; // only try up to 24 bytes
 
-        decode_ws (dec); EXPECT_CH (':');
+          for (;;)
+            {
+              if (p == e || *p < 0x20 || *p >= 0x80 || *p == '\\')
+                {
+                  // slow path, back up and use decode_str
+                  SV *key = decode_str (dec);
+                  if (!key)
+                    goto fail;
 
-        value = decode_sv (dec);
-        if (!value)
-          {
-            SvREFCNT_dec (key);
-            goto fail;
-          }
+                  decode_ws (dec); EXPECT_CH (':');
 
-        hv_store_ent (hv, key, value, 0);
-        SvREFCNT_dec (key);
+                  value = decode_sv (dec);
+                  if (!value)
+                    {
+                      SvREFCNT_dec (key);
+                      goto fail;
+                    }
+
+                  hv_store_ent (hv, key, value, 0);
+                  SvREFCNT_dec (key);
+
+                  break;
+                }
+              else if (*p == '"')
+                {
+                  // fast path, got a simple key
+                  char *key = dec->cur;
+                  int len = p - key;
+                  dec->cur = p + 1;
+
+                  decode_ws (dec); EXPECT_CH (':');
+
+                  value = decode_sv (dec);
+                  if (!value)
+                    goto fail;
+
+                  hv_store (hv, key, len, value, 0);
+
+                  break;
+                }
+
+              ++p;
+            }
+        }
 
         decode_ws (dec);
 
@@ -1135,6 +1175,10 @@
   SvGETMAGIC (string);
   SvUPGRADE (string, SVt_PV);
 
+  if (flags & F_MAXSIZE && SvCUR (string) > DEC_SIZE (flags))
+    croak ("attempted decode of JSON text of %lu bytes size, but max_size is set to %lu",
+           (unsigned long)SvCUR (string), (unsigned long)DEC_SIZE (flags));
+
   if (flags & F_UTF8)
     sv_utf8_downgrade (string, 0);
   else
@@ -1275,6 +1319,25 @@
 
         RETVAL = newSVsv (self);
 }
+	OUTPUT:
+        RETVAL
+
+SV *max_size (SV *self, UV max_size = 0)
+	CODE:
+{
+  	UV *uv = SvJSON (self);
+        UV log2 = 0;
+
+        if (max_size > 0x80000000UL) max_size = 0x80000000UL;
+        if (max_size == 1)           max_size = 2;
+
+        while ((1UL << log2) < max_size)
+          ++log2;
+
+        *uv = *uv & ~F_MAXSIZE | (log2 << S_MAXSIZE);
+
+        RETVAL = newSVsv (self);
+}
 	OUTPUT:
         RETVAL