support/zlib-helper.c

   1 /*
   2  * Used by System.IO.Compression.DeflateStream
   3  *
   4  * Author:
   5  *   Gonzalo Paniagua Javier (gonzalo@novell.com)
   6  *
   7  * (c) Copyright 2009 Novell, Inc.
   8  */
   9 #include <config.h>
  10 #if defined (HAVE_ZLIB)
  11 #include <zlib.h>
  12 #else
  13 #include "zlib.h"
  14 #endif
  15
  16 #include <glib.h>
  17 #include <string.h>
  18 #include <stdlib.h>
  19
  20 #ifndef TRUE
  21 #define FALSE 0
  22 #define TRUE 1
  23 #endif
  24
  25 #define BUFFER_SIZE 4096
  26 #define ARGUMENT_ERROR -10
  27 #define IO_ERROR -11
  28
  29 typedef gint (*read_write_func) (guchar *buffer, gint length, void *gchandle);
  30 struct _ZStream {
  31         z_stream *stream;
  32         guchar *buffer;
  33         read_write_func func;
  34         void *gchandle;
  35         guchar compress;
  36         guchar eof;
  37 };
  38 typedef struct _ZStream ZStream;
  39
  40 ZStream *CreateZStream (gint compress, guchar gzip, read_write_func func, void *gchandle);
  41 gint CloseZStream (ZStream *zstream);
  42 gint Flush (ZStream *stream);
  43 gint ReadZStream (ZStream *stream, guchar *buffer, gint length);
  44 gint WriteZStream (ZStream *stream, guchar *buffer, gint length);
  45
  46 static void *
  47 z_alloc (void *opaque, gsize nitems, gsize item_size)
  48 {
  49         return g_malloc0 (nitems * item_size);
  50 }
  51
  52 static void
  53 z_free (void *opaque, void *ptr)
  54 {
  55         g_free (ptr);
  56 }
  57
  58 ZStream *
  59 CreateZStream (gint compress, guchar gzip, read_write_func func, void *gchandle)
  60 {
  61         z_stream *z;
  62         gint retval;
  63         ZStream *result;
  64
  65         if (func == NULL)
  66                 return NULL;
  67
  68 #if !defined(ZLIB_VERNUM) || (ZLIB_VERNUM < 0x1204)
  69         /* Older versions of zlib do not support raw deflate or gzip */
  70         return NULL;
  71 #endif
  72
  73         z = g_new0 (z_stream, 1);
  74         if (compress) {
  75                 retval = deflateInit2 (z, Z_DEFAULT_COMPRESSION, Z_DEFLATED, gzip ? 31 : -15, 8, Z_DEFAULT_STRATEGY);
  76         } else {
  77                 retval = inflateInit2 (z, gzip ? 31 : -15);
  78         }
  79
  80         if (retval != Z_OK) {
  81                 g_free (z);
  82                 return NULL;
  83         }
  84         z->zalloc = z_alloc;
  85         z->zfree = z_free;
  86         result = g_new0 (ZStream, 1);
  87         result->stream = z;
  88         result->func = func;
  89         result->gchandle = gchandle;
  90         result->compress = compress;
  91         result->buffer = g_new (guchar, BUFFER_SIZE);
  92         return result;
  93 }
  94
  95 gint
  96 CloseZStream (ZStream *zstream)
  97 {
  98         gint status;
  99         gint flush_status;
 100
 101         if (zstream == NULL)
 102                 return ARGUMENT_ERROR;
 103
 104         status = 0;
 105         if (zstream->compress) {
 106                 if (zstream->stream->total_in > 0) {
 107                         do {
 108                                 status = deflate (zstream->stream, Z_FINISH);
 109                                 flush_status = Flush (zstream);
 110                         } while (status == Z_OK); /* We want Z_STREAM_END or error here here */
 111                         if (status == Z_STREAM_END)
 112                                 status = flush_status;
 113                 }
 114                 deflateEnd (zstream->stream);
 115         } else {
 116                 inflateEnd (zstream->stream);
 117         }
 118         g_free (zstream->buffer);
 119         g_free (zstream->stream);
 120         memset (zstream, 0, sizeof (ZStream));
 121         g_free (zstream);
 122         return status;
 123 }
 124
 125 static gint
 126 write_to_managed (ZStream *stream)
 127 {
 128         gint n;
 129         z_stream *zs;
 130
 131         zs = stream->stream;
 132         if (zs->avail_out != BUFFER_SIZE) {
 133                 n = stream->func (stream->buffer, BUFFER_SIZE - zs->avail_out, stream->gchandle);
 134                 zs->next_out = stream->buffer;
 135                 zs->avail_out =  BUFFER_SIZE;
 136                 if (n < 0)
 137                         return IO_ERROR;
 138         }
 139         return 0;
 140 }
 141
 142 gint
 143 Flush (ZStream *stream)
 144 {
 145         if (!stream->compress)
 146                 return 0;
 147
 148         return write_to_managed (stream);
 149 }
 150
 151 gint
 152 ReadZStream (ZStream *stream, guchar *buffer, gint length)
 153 {
 154         gint n;
 155         gint status;
 156         z_stream *zs;
 157
 158         if (stream == NULL || buffer == NULL || length < 0)
 159                 return ARGUMENT_ERROR;
 160
 161         if (stream->eof)
 162                 return 0;
 163
 164         zs = stream->stream;
 165         zs->next_out = buffer;
 166         zs->avail_out = length;
 167         while (zs->avail_out > 0) {
 168                 if (zs->avail_in == 0) {
 169                         n = stream->func (stream->buffer, BUFFER_SIZE, stream->gchandle);
 170                         if (n <= 0) {
 171                                 stream->eof = TRUE;
 172                                 break;
 173                         }
 174                         zs->next_in = stream->buffer;
 175                         zs->avail_in = n;
 176                 }
 177
 178                 status = inflate (stream->stream, Z_SYNC_FLUSH);
 179                 if (status == Z_STREAM_END) {
 180                         stream->eof = TRUE;
 181                         break;
 182                 } else if (status != Z_OK) {
 183                         return status;
 184                 }
 185         }
 186         return length - zs->avail_out;
 187 }
 188
 189 gint
 190 WriteZStream (ZStream *stream, guchar *buffer, gint length)
 191 {
 192         gint n;
 193         gint status;
 194         z_stream *zs;
 195
 196         if (stream == NULL || buffer == NULL || length < 0)
 197                 return ARGUMENT_ERROR;
 198
 199         if (stream->eof)
 200                 return IO_ERROR;
 201
 202         zs = stream->stream;
 203         zs->next_in = buffer;
 204         zs->avail_in = length;
 205         while (zs->avail_in > 0) {
 206                 if (zs->avail_out == 0) {
 207                         zs->next_out = stream->buffer;
 208                         zs->avail_out = BUFFER_SIZE;
 209                 }
 210                 status = deflate (stream->stream, Z_NO_FLUSH);
 211                 if (status != Z_OK && status != Z_STREAM_END)
 212                         return status;
 213
 214                 if (zs->avail_out == 0) {
 215                         n = write_to_managed (stream);
 216                         if (n < 0)
 217                                 return n;
 218                 }
 219         }
 220         return length;
 221 }
 222