From 670a4ae67b83af151c373e9dba7febc660ccf48e Mon Sep 17 00:00:00 2001
From: Alex Shinn <ashinn@users.noreply.github.com>
Date: Thu, 25 Feb 2010 23:58:57 +0900
Subject: [PATCH] adding option to mmap heaps instead of mallocing them

---
 gc.c                     | 14 ++++++++++++--
 include/chibi/features.h |  7 +++++++
 sexp.c                   | 16 ++++++++++++----
 3 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/gc.c b/gc.c
index 5e2a4d23..455b1a85 100644
--- a/gc.c
+++ b/gc.c
@@ -4,6 +4,10 @@
 
 #include "chibi/sexp.h"
 
+#if SEXP_USE_MMAP_GC
+#include <sys/mman.h>
+#endif
+
 /* These settings are configurable but only recommended for */
 /* experienced users, so they're not in config.h.  */
 
@@ -171,8 +175,14 @@ sexp sexp_gc (sexp ctx, size_t *sum_freed) {
 
 sexp_heap sexp_make_heap (size_t size) {
   sexp_free_list free, next;
-  sexp_heap h
-    = (sexp_heap) malloc(sizeof(struct sexp_heap) + size + sexp_heap_align(1));
+  sexp_heap h;
+#if SEXP_USE_MMAP_GC
+  h =  mmap(NULL, sizeof(struct sexp_heap) + size + sexp_heap_align(1),
+            PROT_READ|PROT_WRITE|PROT_EXEC,
+            MAP_ANON|MAP_PRIVATE, 0, 0);
+#else
+  h =  malloc(sizeof(struct sexp_heap) + size + sexp_heap_align(1));
+#endif
   if (! h) return NULL;
   h->size = size;
   h->data = (char*) sexp_heap_align((sexp_uint_t)&(h->data));
diff --git a/include/chibi/features.h b/include/chibi/features.h
index 1a6caed2..d93f5b5c 100644
--- a/include/chibi/features.h
+++ b/include/chibi/features.h
@@ -57,6 +57,9 @@
 /*   explicitly free sexps, though. */
 /* #define SEXP_USE_MALLOC 1 */
 
+/* uncomment this to allocate heaps with mmap instead of malloc */
+/* #define SEXP_USE_MMAP_GC 1 */
+
 /* uncomment this to add conservative checks to the native GC */
 /*   Please mail the author if enabling this makes a bug */
 /*   go away and you're not working on your own C extension. */
@@ -205,6 +208,10 @@
 #define SEXP_USE_MALLOC 0
 #endif
 
+#ifndef SEXP_USE_MMAP_GC
+#define SEXP_USE_MMAP_GC 0
+#endif
+
 #ifndef SEXP_USE_DEBUG_GC
 #define SEXP_USE_DEBUG_GC 0
 #endif
diff --git a/sexp.c b/sexp.c
index d0c41eaf..dd32415d 100644
--- a/sexp.c
+++ b/sexp.c
@@ -290,13 +290,20 @@ sexp sexp_make_context (sexp ctx, sexp_uint_t size) {
 
 #if ! SEXP_USE_GLOBAL_HEAP
 void sexp_destroy_context (sexp ctx) {
-  sexp_heap heap;
+  sexp_heap heap, tmp;
   size_t sum_freed;
   if (sexp_context_heap(ctx)) {
     sexp_sweep(ctx, &sum_freed); /* sweep w/o mark to run finalizers */
     heap = sexp_context_heap(ctx);
     sexp_context_heap(ctx) = NULL;
-    free(heap);
+    for ( ; heap; heap=tmp) {
+      tmp = heap->next;
+#if SEXP_USE_MMAP_GC
+      munmap(heap, heap->size);
+#else
+      free(heap);
+#endif
+    }
   }
 }
 #endif
@@ -702,11 +709,12 @@ sexp sexp_intern(sexp ctx, char *str) {
 #if SEXP_USE_HUFF_SYMS
   res = 0;
   for ( ; (c=*p); p++) {
+    if ((c < 0) || (c > 127))
+      goto normal_intern;
     he = huff_table[(unsigned char)c];
     newbits = he.len;
-    if ((space+newbits) > (sizeof(sexp)*8)) {
+    if ((space+newbits) > (sizeof(sexp)*8))
       goto normal_intern;
-    }
     res |= (((sexp_uint_t) he.bits) << space);
     space += newbits;
   }