1 files changed, 39 insertions, 0 deletions
diff --git a/sys/base/mmap/mmap.c b/sys/base/mmap/mmap.c
new file mode 100644
index 0000000..ce3011c
--- /dev/null
+++ b/sys/base/mmap/mmap.c
@@ -0,0 +1,39 @@
+#include "internal.h"
+
+mmap·Reader
+mmap·open(byte *filename)
+{
+    int     fd;
+    int    err;
+    void  *buf;
+    io·Stream  *s;
+    io·Stat     st;
+
+    s   = io·open(filename, "r");
+    fd  = io·fd(s);
+    err = io·stat(s, &st);
+    if(err){
+        errorf("file stat: error code %d", err);
+        goto ERROR;
+    }
+
+    buf = mmap(nil, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
+    if(!buf){
+        errorf("mmap: failed");
+        goto ERROR;
+    }
+    // NOTE: posix systems require that reference kept to mmap file after fd is closed
+    io·close(s);
+    return (mmap·Reader){.len=st.st_size, .b=buf};
+
+ERROR:
+    io·close(s);
+    return (mmap·Reader){ 0 };
+}
+
+error
+mmap·close(mmap·Reader rdr)
+{
+    munmap(rdr.b, rdr.len);
+    return 0;
+}