src/cairo-deflate-stream.c

   1 /* -*- Mode: c; c-basic-offset: 4; indent-tabs-mode: t; tab-width: 8; -*- */
   2 /* cairo - a vector graphics library with display and print output
   3  *
   4  * Copyright © 2006 Adrian Johnson
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it either under the terms of the GNU Lesser General Public
   8  * License version 2.1 as published by the Free Software Foundation
   9  * (the "LGPL") or, at your option, under the terms of the Mozilla
  10  * Public License Version 1.1 (the "MPL"). If you do not alter this
  11  * notice, a recipient may use your version of this file under either
  12  * the MPL or the LGPL.
  13  *
  14  * You should have received a copy of the LGPL along with this library
  15  * in the file COPYING-LGPL-2.1; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  17  * You should have received a copy of the MPL along with this library
  18  * in the file COPYING-MPL-1.1
  19  *
  20  * The contents of this file are subject to the Mozilla Public License
  21  * Version 1.1 (the "License"); you may not use this file except in
  22  * compliance with the License. You may obtain a copy of the License at
  23  * http://www.mozilla.org/MPL/
  24  *
  25  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
  26  * OF ANY KIND, either express or implied. See the LGPL or the MPL for
  27  * the specific language governing rights and limitations.
  28  *
  29  * The Original Code is the cairo graphics library.
  30  *
  31  * The Initial Developer of the Original Code is Adrian Johnson.
  32  *
  33  * Author(s):
  34  *      Adrian Johnson <ajohnson@redneon.com>
  35  */
  36
  37 #include "cairoint.h"
  38 #include "cairo-output-stream-private.h"
  39 #include <zlib.h>
  40
  41 #define BUFFER_SIZE 16384
  42
  43 typedef struct _cairo_deflate_stream {
  44     cairo_output_stream_t  base;
  45     cairo_output_stream_t *output;
  46     z_stream               zlib_stream;
  47     unsigned char          input_buf[BUFFER_SIZE];
  48     unsigned char          output_buf[BUFFER_SIZE];
  49 } cairo_deflate_stream_t;
  50
  51 static void
  52 cairo_deflate_stream_deflate (cairo_deflate_stream_t *stream, cairo_bool_t flush)
  53 {
  54     int ret;
  55     cairo_bool_t finished;
  56
  57     do {
  58         ret = deflate (&stream->zlib_stream, flush ? Z_FINISH : Z_NO_FLUSH);
  59         if (flush || stream->zlib_stream.avail_out == 0)
  60         {
  61             _cairo_output_stream_write (stream->output,
  62                                         stream->output_buf,
  63                                         BUFFER_SIZE - stream->zlib_stream.avail_out);
  64             stream->zlib_stream.next_out = stream->output_buf;
  65             stream->zlib_stream.avail_out = BUFFER_SIZE;
  66         }
  67
  68         finished = TRUE;
  69         if (stream->zlib_stream.avail_in != 0)
  70             finished = FALSE;
  71         if (flush && ret != Z_STREAM_END)
  72             finished = FALSE;
  73
  74     } while (!finished);
  75
  76     stream->zlib_stream.next_in = stream->input_buf;
  77 }
  78
  79 static cairo_status_t
  80 _cairo_deflate_stream_write (cairo_output_stream_t *base,
  81                              const unsigned char   *data,
  82                              unsigned int           length)
  83 {
  84     cairo_deflate_stream_t *stream = (cairo_deflate_stream_t *) base;
  85     unsigned int count;
  86     const unsigned char *p = data;
  87
  88     while (length) {
  89         count = length;
  90         if (count > BUFFER_SIZE - stream->zlib_stream.avail_in)
  91             count = BUFFER_SIZE - stream->zlib_stream.avail_in;
  92         memcpy (stream->input_buf + stream->zlib_stream.avail_in, p, count);
  93         p += count;
  94         stream->zlib_stream.avail_in += count;
  95         length -= count;
  96
  97         if (stream->zlib_stream.avail_in == BUFFER_SIZE)
  98             cairo_deflate_stream_deflate (stream, FALSE);
  99     }
 100
 101     return _cairo_output_stream_get_status (stream->output);
 102 }
 103
 104 static cairo_status_t
 105 _cairo_deflate_stream_close (cairo_output_stream_t *base)
 106 {
 107     cairo_deflate_stream_t *stream = (cairo_deflate_stream_t *) base;
 108
 109     cairo_deflate_stream_deflate (stream, TRUE);
 110     deflateEnd (&stream->zlib_stream);
 111
 112     return _cairo_output_stream_get_status (stream->output);
 113 }
 114
 115 cairo_output_stream_t *
 116 _cairo_deflate_stream_create (cairo_output_stream_t *output)
 117 {
 118     cairo_deflate_stream_t *stream;
 119
 120     if (output->status)
 121         return _cairo_output_stream_create_in_error (output->status);
 122
 123     stream = malloc (sizeof (cairo_deflate_stream_t));
 124     if (unlikely (stream == NULL)) {
 125         _cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
 126         return (cairo_output_stream_t *) &_cairo_output_stream_nil;
 127     }
 128
 129     _cairo_output_stream_init (&stream->base,
 130                                _cairo_deflate_stream_write,
 131                                NULL,
 132                                _cairo_deflate_stream_close);
 133     stream->output = output;
 134
 135     stream->zlib_stream.zalloc = Z_NULL;
 136     stream->zlib_stream.zfree  = Z_NULL;
 137     stream->zlib_stream.opaque  = Z_NULL;
 138
 139     if (deflateInit (&stream->zlib_stream, Z_DEFAULT_COMPRESSION) != Z_OK) {
 140         free (stream);
 141         return (cairo_output_stream_t *) &_cairo_output_stream_nil;
 142     }
 143
 144     stream->zlib_stream.next_in = stream->input_buf;
 145     stream->zlib_stream.avail_in = 0;
 146     stream->zlib_stream.next_out = stream->output_buf;
 147     stream->zlib_stream.avail_out = BUFFER_SIZE;
 148
 149     return &stream->base;
 150 }