diff --git a/Makefile b/Makefile
index 5652376..2904787 100644
--- a/Makefile
+++ b/Makefile
@@ -43,6 +43,7 @@ buffer_0small.o: buffer/buffer_0small.c buffer.h
 buffer_1.o: buffer/buffer_1.c buffer.h
 buffer_1small.o: buffer/buffer_1small.c buffer.h
 buffer_2.o: buffer/buffer_2.c buffer.h
+buffer_close.o: buffer/buffer_close.c buffer.h
 buffer_feed.o: buffer/buffer_feed.c buffer.h
 buffer_flush.o: buffer/buffer_flush.c buffer.h
 buffer_fromsa.o: buffer/buffer_fromsa.c stralloc.h buffer.h
@@ -66,6 +67,8 @@ buffer_getn.o: buffer/buffer_getn.c byte.h buffer.h
 buffer_getnewline_sa.o: buffer/buffer_getnewline_sa.c stralloc.h \
   buffer.h
 buffer_init.o: buffer/buffer_init.c buffer.h
+buffer_init_free.o: buffer/buffer_init_free.c buffer.h
+buffer_mmapread.o: buffer/buffer_mmapread.c buffer.h mmap.h
 buffer_peek.o: buffer/buffer_peek.c buffer.h
 buffer_put.o: buffer/buffer_put.c byte.h buffer.h
 buffer_put8long.o: buffer/buffer_put8long.c buffer.h fmt.h
@@ -560,7 +563,7 @@ OPEN_OBJS=open_append.o open_excl.o open_read.o open_rw.o open_trunc.o open_writ
 STRALLOC_OBJS=stralloc_append.o stralloc_cat.o stralloc_catb.o stralloc_catlong0.o stralloc_catm_internal.o stralloc_cats.o stralloc_catulong0.o stralloc_chomp.o stralloc_chop.o stralloc_copy.o stralloc_copyb.o stralloc_copys.o stralloc_diff.o stralloc_diffs.o stralloc_free.o stralloc_init.o stralloc_ready.o stralloc_readyplus.o stralloc_starts.o stralloc_zero.o 
 UNIX_OBJS=iopause.o ndelay_off.o ndelay_on.o winsock2errno.o 
 SOCKET_OBJS=fmt_ip4.o fmt_ip6.o fmt_ip6_flat.o fmt_ip6c.o fmt_ip6if.o fmt_ip6ifc.o init.o scan_ip4.o scan_ip6.o scan_ip6_flat.o scan_ip6if.o socket_accept4.o socket_accept6.o socket_bind4.o socket_bind4_reuse.o socket_bind6.o socket_bind6_reuse.o socket_broadcast.o socket_connect4.o socket_connect6.o socket_connected.o socket_getifidx.o socket_getifname.o socket_ip4loopback.o socket_listen.o socket_local4.o socket_local6.o socket_mchopcount6.o socket_mcjoin4.o socket_mcjoin6.o socket_mcleave4.o socket_mcleave6.o socket_mcloop4.o socket_mcloop6.o socket_mcttl4.o socket_noipv6.o socket_recv4.o socket_recv6.o socket_remote4.o socket_remote6.o socket_send4.o socket_send6.o socket_tcp4.o socket_tcp6.o socket_tryreservein.o socket_udp4.o socket_udp6.o socket_v4mappedprefix.o socket_v6any.o socket_v6loopback.o 
-BUFFER_OBJS=buffer_0.o buffer_0small.o buffer_1.o buffer_1small.o buffer_2.o buffer_feed.o buffer_flush.o buffer_fromsa.o buffer_get.o buffer_get_new_token_sa.o buffer_get_new_token_sa_pred.o buffer_get_token.o buffer_get_token_pred.o buffer_get_token_sa.o buffer_get_token_sa_pred.o buffer_getc.o buffer_getline.o buffer_getline_sa.o buffer_getn.o buffer_getnewline_sa.o buffer_init.o buffer_peek.o buffer_put.o buffer_put8long.o buffer_putalign.o buffer_puterror.o buffer_puterror2.o buffer_putflush.o buffer_putlong.o buffer_putlonglong.o buffer_putm_internal.o buffer_putm_internal_flush.o buffer_putnlflush.o buffer_puts.o buffer_putsa.o buffer_putsaflush.o buffer_putsalign.o buffer_putsflush.o buffer_putspace.o buffer_putulong.o buffer_putulonglong.o buffer_putxlong.o buffer_seek.o buffer_stubborn.o buffer_stubborn2.o errmsg_cvt.o errmsg_iam.o errmsg_info.o errmsg_infosys.o errmsg_warn.o errmsg_warnsys.o errmsg_writesys.o 
+BUFFER_OBJS=buffer_0.o buffer_0small.o buffer_1.o buffer_1small.o buffer_2.o buffer_close.o buffer_feed.o buffer_flush.o buffer_fromsa.o buffer_get.o buffer_get_new_token_sa.o buffer_get_new_token_sa_pred.o buffer_get_token.o buffer_get_token_pred.o buffer_get_token_sa.o buffer_get_token_sa_pred.o buffer_getc.o buffer_getline.o buffer_getline_sa.o buffer_getn.o buffer_getnewline_sa.o buffer_init.o buffer_init_free.o buffer_mmapread.o buffer_peek.o buffer_put.o buffer_put8long.o buffer_putalign.o buffer_puterror.o buffer_puterror2.o buffer_putflush.o buffer_putlong.o buffer_putlonglong.o buffer_putm_internal.o buffer_putm_internal_flush.o buffer_putnlflush.o buffer_puts.o buffer_putsa.o buffer_putsaflush.o buffer_putsalign.o buffer_putsflush.o buffer_putspace.o buffer_putulong.o buffer_putulonglong.o buffer_putxlong.o buffer_seek.o buffer_stubborn.o buffer_stubborn2.o errmsg_cvt.o errmsg_iam.o errmsg_info.o errmsg_infosys.o errmsg_warn.o errmsg_warnsys.o errmsg_writesys.o 
 MMAP_OBJS=mmap_private.o mmap_read.o mmap_shared.o 
 TAIA_OBJS=taia_add.o taia_addsec.o taia_approx.o taia_frac.o taia_less.o taia_now.o taia_pack.o taia_sub.o taia_tai.o taia_uint.o taia_unpack.o 
 TAI_OBJS=tai_add.o tai_now.o tai_pack.o tai_sub.o tai_uint.o tai_unpack.o 
diff --git a/buffer.h b/buffer.h
index 2e31cd0..eb99429 100644
--- a/buffer.h
+++ b/buffer.h
@@ -8,14 +8,19 @@ typedef struct buffer {
   unsigned long int a;	/* allocated buffer size */
   int fd;		/* passed as first argument to op */
   int (*op)();		/* use read(2) or write(2) */
+  enum { NOTHING, FREE, MUNMAP } todo;
 } buffer;
 
-#define BUFFER_INIT(op,fd,buf,len) { (buf), 0, 0, (len), (fd), (op) }
+#define BUFFER_INIT(op,fd,buf,len) { (buf), 0, 0, (len), (fd), (op), NOTHING }
+#define BUFFER_INIT_FREE(op,fd,buf,len) { (buf), 0, 0, (len), (fd), (op), FREE }
 #define BUFFER_INIT_READ(op,fd,buf,len) BUFFER_INIT(op,fd,buf,len) /*obsolete*/
 #define BUFFER_INSIZE 8192
 #define BUFFER_OUTSIZE 8192
 
 void buffer_init(buffer* b,int (*op)(),int fd,unsigned char* y,unsigned long int ylen);
+void buffer_init_free(buffer* b,int (*op)(),int fd,unsigned char* y,unsigned long int ylen);
+int buffer_mmapread(buffer* b,const char* filename);
+void buffer_close(buffer* b);
 
 int buffer_flush(buffer* b);
 int buffer_put(buffer* b,const unsigned char* x,unsigned long int len);
diff --git a/buffer/buffer_close.3 b/buffer/buffer_close.3
new file mode 100644
index 0000000..aecae97
--- /dev/null
+++ b/buffer/buffer_close.3
@@ -0,0 +1,13 @@
+.TH buffer_close 3
+.SH NAME
+buffer_close \- close buffer
+.SH SYNTAX
+.B #include <buffer.h>
+
+void \fBbuffer_close\fP(buffer* \fIb\fR);
+.SH DESCRIPTION
+buffer_close close the file associated with the buffer and frees/unmaps
+the memory associated with the buffer if buffer_init_free or
+buffer_mmapread were used.
+.SH "SEE ALSO"
+buffer_init(3), buffer_init_free(3), buffer_mmapread(3)
diff --git a/buffer/buffer_close.c b/buffer/buffer_close.c
new file mode 100644
index 0000000..6d8127a
--- /dev/null
+++ b/buffer/buffer_close.c
@@ -0,0 +1,13 @@
+#include <buffer.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+void buffer_close(buffer* b) {
+  if (b->fd != -1) close(b->fd);
+  switch (b->todo) {
+  case FREE: free(b->x); break;
+  case MUNMAP: munmap(b->x,b->a); break;
+  default: ;
+  }
+}
diff --git a/buffer/buffer_init.c b/buffer/buffer_init.c
index 9644154..208b54b 100644
--- a/buffer/buffer_init.c
+++ b/buffer/buffer_init.c
@@ -8,4 +8,5 @@ void buffer_init(buffer* b,int (*op)(),int fd,
   b->a=ylen;
   b->p=0;
   b->n=0;
+  b->todo=NOTHING;
 }
diff --git a/buffer/buffer_init_free.3 b/buffer/buffer_init_free.3
new file mode 100644
index 0000000..e16eb83
--- /dev/null
+++ b/buffer/buffer_init_free.3
@@ -0,0 +1,14 @@
+.TH buffer_init_free 3
+.SH NAME
+buffer_init_free \- initialize buffer structure
+.SH SYNTAX
+.B #include <buffer.h>
+
+int \fBbuffer_init_free\fR(buffer &\fIb\fR,
+                int (*\fIop\fR)(int,char*,unsigned int),
+                int \fIfd\fR, unsigned char* \fIy\fR, unsigned long int \fIylen\fR);
+.SH DESCRIPTION
+buffer_init_free is like buffer_init except that the memory (\fIy\fR is
+marked to be freed by buffer_close().
+.SH "SEE ALSO"
+buffer_init(3), buffer_mmap_read(3), buffer(3)
diff --git a/buffer/buffer_init_free.c b/buffer/buffer_init_free.c
new file mode 100644
index 0000000..4fe851e
--- /dev/null
+++ b/buffer/buffer_init_free.c
@@ -0,0 +1,7 @@
+#include "buffer.h"
+
+void buffer_init_free(buffer* b,int (*op)(),int fd,
+		 unsigned char* y,unsigned long int ylen) {
+  buffer_init(b,op,fd,y,ylen);
+  b->todo=FREE;
+}
diff --git a/buffer/buffer_mmapread.3 b/buffer/buffer_mmapread.3
new file mode 100644
index 0000000..f6cdbbf
--- /dev/null
+++ b/buffer/buffer_mmapread.3
@@ -0,0 +1,29 @@
+.TH buffer_mmapread 3
+.SH NAME
+buffer_mmapread \- create read-only memory-mapped file buffer
+.SH SYNTAX
+.B #include <buffer.h>
+
+int \fBbuffer_mmapread\fR(buffer &\fIb\fR,const char* \fIfilename\fR);
+.SH DESCRIPTION
+buffer_mmapread opens \fIfilename\fR for reading and fills \fIb\fR so
+that the contents of the file can be read from it.  Using mmap is more
+efficient than reading through a real buffer, but you have to call
+buffer_close to unmap the memory in the end.
+.SH EXAMPLE
+  #include <buffer.h>
+  #include <open.h>
+
+  buffer input;
+  char x;
+
+  buffer_mmapread(&input,"/etc/passwd");
+  while (buffer_get(&input,&x,1)==1) {
+    buffer_put(buffer_1,&x,1);
+    if (x=='\\n') break;
+  }
+  buffer_flush(buffer_1);
+  buffer_close(&input);
+
+.SH "SEE ALSO"
+buffer_flush(3), buffer(3)
diff --git a/buffer/buffer_mmapread.c b/buffer/buffer_mmapread.c
new file mode 100644
index 0000000..858bf9b
--- /dev/null
+++ b/buffer/buffer_mmapread.c
@@ -0,0 +1,15 @@
+#include <buffer.h>
+#include <mmap.h>
+
+static int op() {
+  return 0;
+}
+
+int buffer_mmapread(buffer* b,const char* filename) {
+  if (!(b->x=mmap_read(filename,&b->n))) return -1;
+  b->p=0; b->a=b->n;
+  b->fd=-1;
+  b->op=op;
+  b->todo=MUNMAP;
+  return 0;
+}
diff --git a/test/buffer_mmap.c b/test/buffer_mmap.c
new file mode 100644
index 0000000..78fedf6
--- /dev/null
+++ b/test/buffer_mmap.c
@@ -0,0 +1,13 @@
+#include <buffer.h>
+
+int main() {
+  buffer input;
+  char x;
+  buffer_mmapread(&input,"/etc/passwd");
+  while (buffer_get(&input,&x,1)==1) {
+    buffer_put(buffer_1,&x,1);
+    if (x=='\n') break;
+  }
+  buffer_flush(buffer_1);
+  buffer_close(&input);
+}