2002-03-14 Marcus Brinkmann <marcus@gnu.org>

	* unzipstore.c (unzip_store): New variable IN_BUF_SIZE to hold
	allocated space for IN_BUF.  Use that instead IN_BUF_LEN for that
	purpose if appropriate.  Always update IN_BUF_LEN after a read.
2002-03-11  Roland McGrath  <roland@frob.com>

	* unzipstore.c: New file, broken out of bunzip2.c.
	* bunzip2.c: Most code moved to unzipstore.c, which we #include.
	(DO_UNZIP, UNZIP): New function, macro.
	* gunzip.c: Most code deleted, now in unzipstore.c, which we #include.
	(DO_UNZIP, UNZIP): New function, macro.
	* Makefile (DIST_FILES): New variable, list unzipstore.c here.

1 files changed, 267 insertions, 0 deletions

diff --git a/libstore/unzipstore.c b/libstore/unzipstore.c
new file mode 100644
index 00000000..35e9e7af
--- /dev/null
+++ b/libstore/unzipstore.c
@@ -0,0 +1,267 @@
+/* Decompressing store backend (common code for gunzip and bunzip2)
+
+   Copyright (C) 1998, 1999, 2002 Free Software Foundation, Inc.
+   Written by okuji@kuicr.kyoto-u.ac.jp <okuji@kuicr.kyoto-u.ac.jp>
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   The GNU Hurd is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */
+
+#include <stdio.h>
+#include <string.h>
+#include <setjmp.h>
+#include <cthreads.h>
+#include <sys/mman.h>
+
+#include "store.h"
+
+#define IN_BUFFERING  (256*1024)
+#define OUT_BUFFERING (512*1024)
+
+static struct mutex unzip_lock = MUTEX_INITIALIZER;
+
+#define STORE_UNZIP(name)		STORE_UNZIP_1 (UNZIP, name)
+#define STORE_UNZIP_1(unzip,name)	STORE_UNZIP_2 (unzip, name)
+#define STORE_UNZIP_2(unzip,name)	store_##unzip##_##name
+#define STORE_STD_CLASS_1(name) STORE_STD_CLASS(name)
+#define STRINGIFY(name) STRINGIFY_1(name)
+#define STRINGIFY_1(name) #name
+
+
+/* Uncompress the contents of FROM, which should contain a valid bzip2 file,
+   into memory, returning the result buffer in BUF & BUF_LEN.  */
+static error_t
+unzip_store (struct store *from, void **buf, size_t *buf_len)
+{
+  /* Callbacks from decompression engine for I/O and error interface.  */
+  extern int (*unzip_read) (char *buf, size_t maxread);
+  extern void (*unzip_write) (const char *buf, size_t nwrite);
+  extern void (*unzip_read_error) (void);
+  extern void (*unzip_error) (const char *msg);
+
+  /* How we return errors from our hook functions.  */
+  jmp_buf zerr_jmp_buf;
+  error_t zerr;
+
+  /* vm_alloced buffer for the input store.  */
+  void *in_buf = 0;
+  size_t in_buf_len = 0;	/* Amount of valid data in IN_BUF.  */
+  size_t in_buf_size = 0;	/* Allocated space for IN_BUF.  */
+  size_t in_buf_offs = 0;	/* Offset of read point in IN_BUF.  */
+  off_t in_buf_addr = 0;	/* Address in FROM of *next* IN_BUF.  */
+
+  /* Buffer input in units that are least IN_BUFFERING bytes, but are also a
+     multiple of FROM's block size.  */
+  size_t in_addr_mask = ((1 << from->log2_block_size) - 1);
+  size_t in_buffering = ((IN_BUFFERING + in_addr_mask) & ~in_addr_mask);
+
+  /* Read at most MAXREAD (or 0 if eof) bytes into BUF from our current
+     position in FROM.  */
+  int zread (char *buf, size_t maxread)
+    {
+      size_t did_read = 0;
+
+      while (maxread > 0)
+	{
+	  size_t left = in_buf_len - in_buf_offs;
+
+	  if (left > 0)
+	    /* Fill BUF with what we can from IN_BUF.  */
+	    {
+	      if (left > maxread)
+		left = maxread;
+	      bcopy (in_buf + in_buf_offs, buf, left);
+	      in_buf_offs += left;
+	      buf += left;
+	      maxread -= left;
+	      did_read += left;
+	    }
+
+	  /* Limit MAXREAD to the number of bytes left in the input.  */
+	  if (maxread > (from->size - (in_buf_addr << from->log2_block_size)))
+	    maxread = from->size - (in_buf_addr << from->log2_block_size);
+
+	  if (maxread > 0)
+	    /* Have to fill IN_BUF again.  */
+	    {
+	      void *new_in_buf = in_buf;
+	      size_t new_in_buf_len = in_buf_len;
+
+	      zerr = store_read (from, in_buf_addr, in_buffering,
+				 &new_in_buf, &new_in_buf_len);
+	      if (zerr)
+		longjmp (zerr_jmp_buf, 1);
+
+	      in_buf_addr += (new_in_buf_len >> from->log2_block_size);
+
+	      if (new_in_buf != in_buf)
+		{
+		  if (in_buf_size > 0)
+		    munmap (in_buf, in_buf_size);
+		  in_buf = new_in_buf;
+		  in_buf_size = new_in_buf_len;
+		}
+
+	      in_buf_len = new_in_buf_len;
+	      in_buf_offs = 0;
+	    }
+	}
+      return did_read;
+    }
+
+  size_t out_buf_offs = 0;	/* Position in the output buffer.  */
+
+  /* Write compress data to our output buffer.  */
+  void zwrite (const char *wbuf, size_t nwrite)
+    {
+      size_t old_buf_len = *buf_len;
+
+      if (out_buf_offs + nwrite > old_buf_len)
+	/* Have to grow the output buffer.  */
+	{
+	  void *old_buf = *buf;
+	  void *new_buf = old_buf + old_buf_len; /* First try.  */
+	  size_t new_buf_len = round_page (old_buf_len + old_buf_len + nwrite);
+
+	  /* Try to grow the buffer.  */
+	  zerr =
+	    vm_allocate (mach_task_self (),
+			 (vm_address_t *)&new_buf, new_buf_len - old_buf_len,
+			 0);
+	  if (zerr)
+	    /* Can't do that, try to make a bigger buffer elsewhere.  */
+	    {
+	      new_buf = mmap (0, new_buf_len, PROT_READ|PROT_WRITE,
+			      MAP_ANON, 0, 0);
+	      zerr = (new_buf == (void *) -1) ? errno : 0;
+	      if (zerr)
+		longjmp (zerr_jmp_buf, 1);
+
+	      if (out_buf_offs > 0)
+		/* Copy the old buffer into the start of the new & free it. */
+		bcopy (old_buf, new_buf, out_buf_offs);
+
+	      munmap (old_buf, old_buf_len);
+
+	      *buf = new_buf;
+	    }
+
+	  *buf_len = new_buf_len;
+	}
+
+      bcopy (wbuf, *buf + out_buf_offs, nwrite);
+      out_buf_offs += nwrite;
+    }
+
+  void zreaderr (void)
+    {
+      zerr = EIO;
+      longjmp (zerr_jmp_buf, 1);
+    }
+  void zerror (const char *msg)
+    {
+      zerr = EINVAL;
+      longjmp (zerr_jmp_buf, 2);
+    }
+
+  /* Try to guess a reasonable output buffer size.  */
+  *buf_len = round_page (from->size * 2);
+  *buf = mmap (0, *buf_len, PROT_READ|PROT_WRITE, MAP_ANON, 0, 0);
+  zerr = (*buf == (void *) -1) ? errno : 0;
+  if (zerr)
+    return zerr;
+
+  mutex_lock (&unzip_lock);
+
+  unzip_read = zread;
+  unzip_write = zwrite;
+  unzip_read_error = zreaderr;
+  unzip_error = zerror;
+
+  if (! setjmp (zerr_jmp_buf))
+    {
+      /* Call the decompression engine.  */
+      zerr = DO_UNZIP ();
+    }
+
+  mutex_unlock (&unzip_lock);
+
+  if (in_buf_size > 0)
+    munmap (in_buf, in_buf_size);
+
+  if (zerr)
+    {
+      if (*buf_len > 0)
+	munmap (*buf, *buf_len);
+    }
+  else if (out_buf_offs < *buf_len)
+    /* Trim the output buffer to be the right length.  */
+    {
+      size_t end = round_page (out_buf_offs);
+      if (end < *buf_len)
+	munmap (*buf + end, *buf_len - end);
+      *buf_len = out_buf_offs;
+    }
+
+  return zerr;
+}
+
+
+/* Return a new store in STORE which contains a snapshot of the uncompressed
+   contents of the store FROM; FROM is consumed.  */
+error_t
+STORE_UNZIP(create) (struct store *from, int flags, struct store **store)
+{
+  void *buf;
+  size_t buf_len;
+  error_t err = unzip_store (from, &buf, &buf_len);
+
+  if (! err)
+    {
+      err = store_buffer_create (buf, buf_len, flags, store);
+      if (err)
+	munmap (buf, buf_len);
+      else
+	store_free (from);
+    }
+
+  return err;
+}
+
+/* Open the compressed store NAME -- which consists of another store-class
+   name, a ':', and a name for that store class to open -- and return the
+   corresponding store in STORE.  CLASSES is used to select classes
+   specified by the type name; if it is 0, STORE_STD_CLASSES is used.  */
+error_t
+STORE_UNZIP(open) (const char *name, int flags,
+		    const struct store_class *const *classes,
+		    struct store **store)
+{
+  struct store *from;
+  error_t err =
+    store_typed_open (name, flags | STORE_HARD_READONLY, classes, &from);
+
+  if (! err)
+    {
+      err = STORE_UNZIP(create) (from, flags, store);
+      if (err)
+	store_free (from);
+    }
+
+  return err;
+}
+
+const struct store_class STORE_UNZIP(class) =
+{ -1, STRINGIFY(UNZIP), open: STORE_UNZIP(open) };
+STORE_STD_CLASS_1 (UNZIP);