Index: Doc/lib/libzlib.tex
===================================================================
RCS file: /cvsroot/python/python/dist/src/Doc/lib/libzlib.tex,v
retrieving revision 1.23
diff -c -2 -r1.23 libzlib.tex
*** Doc/lib/libzlib.tex	2000/10/18 17:43:06	1.23
--- Doc/lib/libzlib.tex	2001/02/22 12:05:44
***************
*** 117,121 ****
  \end{methoddesc}
  
! Decompression objects support the following methods, and a single attribute:
  
  \begin{memberdesc}{unused_data}
--- 117,121 ----
  \end{methoddesc}
  
! Decompression objects support the following methods, and two attributes:
  
  \begin{memberdesc}{unused_data}
***************
*** 132,136 ****
  \end{memberdesc}
  
! \begin{methoddesc}[Decompress]{decompress}{string}
  Decompress \var{string}, returning a string containing the
  uncompressed data corresponding to at least part of the data in
--- 132,136 ----
  \end{memberdesc}
  
! \begin{methoddesc}[Decompress]{decompress}{string}{\optional{max_length}}
  Decompress \var{string}, returning a string containing the
  uncompressed data corresponding to at least part of the data in
***************
*** 139,142 ****
--- 139,150 ----
  \method{decompress()} method.  Some of the input data may be preserved
  in internal buffers for later processing.
+ If the optional parameter max_length is supplied then the return value
+ will be no longer than max_length. This may mean that not all of the
+ compressed input can be processed; and unconsumed data will be stored
+ in the attribute \member{unconsumed_tail}. This string must be passed to
+ a subsequent call to \method{decompress()} if decompression is to
+ continue.
+ If max_length is not supplied then the whole input is decompressed, and
+ \member{unconsumed_tail} set to None.
  \end{methoddesc}
  
Index: Lib/test/test_zlib.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/test/test_zlib.py,v
retrieving revision 1.13
diff -c -2 -r1.13 test_zlib.py
*** Lib/test/test_zlib.py	2001/02/21 07:29:48	1.13
--- Lib/test/test_zlib.py	2001/02/22 12:06:43
***************
*** 77,80 ****
--- 77,100 ----
      print "decompressobj with init options succeeded"
  
+ print "should be None:",deco.unconsumed_tail
+ 
+ deco = zlib.decompressobj(-12)
+ cb = combuf[:]
+ bufs = []
+ while cb:
+     max_length = 1 + len(cb)/10
+     chunk = deco.decompress(cb,max_length)
+     if len(chunk)>max_length:
+         print 'chunk too big (%d>%d)' % (len(chunk),max_length)
+     bufs.append(chunk)
+     cb = deco.unconsumed_tail
+ bufs.append(deco.flush())
+ decomp2 = ''.join(buf)
+ if decomp2 != buf:
+     print "max_length decompressobj failed"
+ else:
+     print "max_length decompressobj succeeded"
+ 
+ 
  # Test flush() with the various options, using all the different levels
  # in order to provide more variations.
Index: Lib/test/output/test_zlib
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/test/output/test_zlib,v
retrieving revision 1.3
diff -c -2 -r1.3 test_zlib
*** Lib/test/output/test_zlib	1998/04/24 18:31:28	1.3
--- Lib/test/output/test_zlib	2001/02/22 12:06:56
***************
*** 9,10 ****
--- 9,12 ----
  decompress with init options succeeded
  decompressobj with init options succeeded
+ should be None: None
+ max_length decompressobj succeeded
Index: Modules/zlibmodule.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Modules/zlibmodule.c,v
retrieving revision 2.39
diff -c -2 -r2.39 zlibmodule.c
*** Modules/zlibmodule.c	2001/02/21 02:15:56	2.39
--- Modules/zlibmodule.c	2001/02/22 12:07:05
***************
*** 31,34 ****
--- 31,35 ----
    z_stream zst;
    PyObject *unused_data;
+   PyObject *unconsumed_tail;
    int is_initialised;
  } compobject;
***************
*** 53,56 ****
--- 54,58 ----
  	self->is_initialised = 0;
  	self->unused_data = PyString_FromString("");
+ 	self->unconsumed_tail = NULL;
          return self;
  }
***************
*** 376,379 ****
--- 378,382 ----
        deflateEnd(&self->zst);
      Py_XDECREF(self->unused_data);
+     Py_XDECREF(self->unconsumed_tail);
      PyObject_Del(self);
  }
***************
*** 385,388 ****
--- 388,392 ----
        inflateEnd(&self->zst);
      Py_XDECREF(self->unused_data);
+     Py_XDECREF(self->unconsumed_tail);
      PyObject_Del(self);
  }
***************
*** 447,454 ****
  
  static char decomp_decompress__doc__[] =
! "decompress(data) -- Return a string containing the decompressed version of the data.\n\n"
  "After calling this function, some of the input data may still\n"
  "be stored in internal buffers for later processing.\n"
! "Call the flush() method to clear these buffers."
  ;
  
--- 451,460 ----
  
  static char decomp_decompress__doc__[] =
! "decompress(data,max_length) -- Return a string containing the decompressed version of the data.\n\n"
  "After calling this function, some of the input data may still\n"
  "be stored in internal buffers for later processing.\n"
! "Call the flush() method to clear these buffers.\n"
! "If the max_length parameter is specified then the return value will be no longer than max_length.\n"
! "Unconsumed input data will stored in the unconsumed_tail attribute."
  ;
  
***************
*** 456,466 ****
  PyZlib_objdecompress(compobject *self, PyObject *args)
  {
!   int err, inplen, length = DEFAULTALLOC;
    PyObject *RetVal;
    Byte *input;
    unsigned long start_total_out;
  
!   if (!PyArg_ParseTuple(args, "s#:decompress", &input, &inplen))
      return NULL;
    if (!(RetVal = PyString_FromStringAndSize(NULL, length))) {
      PyErr_SetString(PyExc_MemoryError,
--- 462,482 ----
  PyZlib_objdecompress(compobject *self, PyObject *args)
  {
!   int err, inplen, old_length, length = DEFAULTALLOC;
!   int max_length = 0;
    PyObject *RetVal;
    Byte *input;
    unsigned long start_total_out;
  
!   Py_XDECREF(self->unconsumed_tail);
!   self->unconsumed_tail = NULL;
! 
!   if (!PyArg_ParseTuple(args, "s#|i:decompress", &input, &inplen, &max_length))
!     return NULL;
!   if (max_length<0) {
!     PyErr_SetString(PyExc_ValueError,
! 		    "max_length must be greater than zero");
      return NULL;
+   }
+   if(max_length && length>max_length) length = max_length;
    if (!(RetVal = PyString_FromStringAndSize(NULL, length))) {
      PyErr_SetString(PyExc_MemoryError,
***************
*** 476,490 ****
    /* while Z_OK and the output buffer is full, there might be more output,
      so extend the output buffer and try again */
!   while (err == Z_OK && self->zst.avail_out == 0) { 
!     if (_PyString_Resize(&RetVal, length << 1) == -1) {
        PyErr_SetString(PyExc_MemoryError,
                        "Can't allocate memory to compress data");
        return NULL;
      }
!     self->zst.next_out = (unsigned char *)PyString_AsString(RetVal) + length;
!     self->zst.avail_out = length;
!     length = length << 1;
      err = inflate(&(self->zst), Z_SYNC_FLUSH);
    }
    /* The end of the compressed data has been reached, so set the unused_data 
      attribute to a string containing the remainder of the data in the string. 
--- 492,518 ----
    /* while Z_OK and the output buffer is full, there might be more output,
      so extend the output buffer and try again */
!   while (err == Z_OK && self->zst.avail_out == 0 && (!max_length || length<max_length) ) { 
!     old_length = length;
!     length = length << 1;
!     if(max_length && length>max_length) length = max_length;
!     if (_PyString_Resize(&RetVal, length) == -1) {
        PyErr_SetString(PyExc_MemoryError,
                        "Can't allocate memory to compress data");
        return NULL;
      }
!     self->zst.next_out = (unsigned char *)PyString_AsString(RetVal) + old_length;
!     self->zst.avail_out = length-old_length;
      err = inflate(&(self->zst), Z_SYNC_FLUSH);
    }
+   /* Not all of the compressed data could be accomodated in the output buffer
+     of specified size. Return the unconsumed tail in an attribute.*/
+   if(max_length) {
+     if(!(self->unconsumed_tail=PyString_FromStringAndSize(self->zst.next_in, self->zst.avail_in))) {
+       PyErr_SetString(PyExc_MemoryError,
+                       "Can't allocate memory to unconsumed_tail");
+       return NULL;
+     }
+   }
+ 
    /* The end of the compressed data has been reached, so set the unused_data 
      attribute to a string containing the remainder of the data in the string. 
***************
*** 658,661 ****
--- 686,702 ----
  	    Py_INCREF(self->unused_data);
  	    return self->unused_data;
+ 	  }
+         if (strcmp(name, "unconsumed_tail") == 0) 
+ 	  {  
+ 	    if(self->unconsumed_tail) 
+ 	    {
+ 	      Py_INCREF(self->unused_data);
+ 	      return self->unused_data;
+ 	    }
+ 	    else
+ 	    {
+ 	      Py_INCREF(Py_None);
+ 	      return Py_None;
+ 	    }
  	  }
          return Py_FindMethod(Decomp_methods, (PyObject *)self, name);