bulk upload of source

1 files changed, 51 insertions, 0 deletions

diff --git a/mmap_alloca.h b/mmap_alloca.h
new file mode 100644
index 0000000..20b9d89
--- /dev/null
+++ b/mmap_alloca.h
@@ -0,0 +1,51 @@
+#ifndef INIT_MMAP
+
+#define depends_alloca(N)	alloca(N)
+#define read_alloca(N)		alloca(N)
+#define INIT_FREE_MEMBLOCKS(X)	X
+#define free_execve(...)	execve(__VA_ARGS__)
+
+
+#else
+#include <sys/mman.h>
+#include <sys/shm.h>	/* for PAGE_SIZE */
+#ifndef PAGE_SIZE
+#define PAGE_SIZE 4096
+#endif
+
+#define depends_alloca(N)	mmap_alloca(N)
+#define read_alloca(N) \
+  ((read_buf) ? read_buf : (read_buf=mmap_alloca(N)))
+
+#define INIT_FREE_MEMBLOCKS(X)	read_buf=0; mmap_free(); X
+#define free_execve(...)	mmap_free(); execve(__VA_ARGS__)
+
+#define mem_x_size ((sizeof(struct memalloc) + 16) & ~15)
+static struct memalloc *mroot;
+static void *read_buf;
+
+static void *mmap_alloca(uint32t n) {
+  n = (n + 16) & ~15;
+  if (mroot == 0 || n + mem_x_size >= mroot->r) {
+    struct memalloc *m;
+    uint32t len = (n + (PAGE_SIZE + mem_x_size)) & ~(PAGE_SIZE-1);
+    m = mmap(0,len,PROT_READ|PROT_WRITE,MAP_ANONYMOUS|MAP_PRIVATE,-1,0);
+    if (m == (struct memalloc *)-1) return 0;
+    m->x = mroot;	/* previous block */
+    m->a = len;
+    m->r = len;
+    mroot = m;
+  }
+  mroot->r -= n;
+  return (void *)mroot + mroot->r;
+}
+#undef mem_x_size
+
+static void mmap_free() {
+  while (mroot) {
+    void *x = mroot->x;
+    munmap(mroot,mroot->a);
+    mroot = x;
+  }
+}
+#endif