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 static gint flush_internal (ZStream *stream, gboolean is_final);
  46
  47 static void *
  48 z_alloc (void *opaque, gsize nitems, gsize item_size)
  49 {
  50         return g_malloc0 (nitems * item_size);
  51 }
  52
  53 static void
  54 z_free (void *opaque, void *ptr)
  55 {
  56         g_free (ptr);
  57 }
  58
  59 ZStream *
  60 CreateZStream (gint compress, guchar gzip, read_write_func func, void *gchandle)
  61 {
  62         z_stream *z;
  63         gint retval;
  64         ZStream *result;
  65
  66         if (func == NULL)
  67                 return NULL;
  68
  69 #if !defined(ZLIB_VERNUM) || (ZLIB_VERNUM < 0x1204)
  70         /* Older versions of zlib do not support raw deflate or gzip */
  71         return NULL;
  72 #endif
  73
  74         z = g_new0 (z_stream, 1);
  75         if (compress) {
  76                 retval = deflateInit2 (z, Z_DEFAULT_COMPRESSION, Z_DEFLATED, gzip ? 31 : -15, 8, Z_DEFAULT_STRATEGY);
  77         } else {
  78                 retval = inflateInit2 (z, gzip ? 31 : -15);
  79         }
  80
  81         if (retval != Z_OK) {
  82                 g_free (z);
  83                 return NULL;
  84         }
  85         z->zalloc = z_alloc;
  86         z->zfree = z_free;
  87         result = g_new0 (ZStream, 1);
  88         result->stream = z;
  89         result->func = func;
  90         result->gchandle = gchandle;
  91         result->compress = compress;
  92         result->buffer = g_new (guchar, BUFFER_SIZE);
  93         return result;
  94 }
  95
  96 gint
  97 CloseZStream (ZStream *zstream)
  98 {
  99         gint status;
 100         gint flush_status;
 101
 102         if (zstream == NULL)
 103                 return ARGUMENT_ERROR;
 104
 105         status = 0;
 106         if (zstream->compress) {
 107                 if (zstream->stream->total_in > 0) {
 108                         do {
 109                                 status = deflate (zstream->stream, Z_FINISH);
 110                                 flush_status = flush_internal (zstream, TRUE);
 111                         } while (status == Z_OK); /* We want Z_STREAM_END or error here here */
 112                         if (status == Z_STREAM_END)
 113                                 status = flush_status;
 114                 }
 115                 deflateEnd (zstream->stream);
 116         } else {
 117                 inflateEnd (zstream->stream);
 118         }
 119         g_free (zstream->buffer);
 120         g_free (zstream->stream);
 121         memset (zstream, 0, sizeof (ZStream));
 122         g_free (zstream);
 123         return status;
 124 }
 125
 126 static gint
 127 write_to_managed (ZStream *stream)
 128 {
 129         gint n;
 130         z_stream *zs;
 131
 132         zs = stream->stream;
 133         if (zs->avail_out != BUFFER_SIZE) {
 134                 n = stream->func (stream->buffer, BUFFER_SIZE - zs->avail_out, stream->gchandle);
 135                 zs->next_out = stream->buffer;
 136                 zs->avail_out = BUFFER_SIZE;
 137                 if (n < 0)
 138                         return IO_ERROR;
 139         }
 140         return 0;
 141 }
 142
 143 static gint
 144 flush_internal (ZStream *stream, gboolean is_final)
 145 {
 146         gint status;
 147
 148         if (!stream->compress)
 149                 return 0;
 150
 151         if (!is_final) {
 152                 status = deflate (stream->stream, Z_PARTIAL_FLUSH);
 153                 if (status != Z_OK && status != Z_STREAM_END)
 154                         return status;
 155         }
 156         return write_to_managed (stream);
 157 }
 158
 159 gint
 160 Flush (ZStream *stream)
 161 {
 162         return flush_internal (stream, FALSE);
 163 }
 164
 165 gint
 166 ReadZStream (ZStream *stream, guchar *buffer, gint length)
 167 {
 168         gint n;
 169         gint status;
 170         z_stream *zs;
 171
 172         if (stream == NULL || buffer == NULL || length < 0)
 173                 return ARGUMENT_ERROR;
 174
 175         if (stream->eof)
 176                 return 0;
 177
 178         zs = stream->stream;
 179         zs->next_out = buffer;
 180         zs->avail_out = length;
 181         while (zs->avail_out > 0) {
 182                 if (zs->avail_in == 0) {
 183                         n = stream->func (stream->buffer, BUFFER_SIZE, stream->gchandle);
 184                         if (n <= 0) {
 185                                 stream->eof = TRUE;
 186                                 break;
 187                         }
 188                         zs->next_in = stream->buffer;
 189                         zs->avail_in = n;
 190                 }
 191
 192                 status = inflate (stream->stream, Z_SYNC_FLUSH);
 193                 if (status == Z_STREAM_END) {
 194                         stream->eof = TRUE;
 195                         break;
 196                 } else if (status != Z_OK) {
 197                         return status;
 198                 }
 199         }
 200         return length - zs->avail_out;
 201 }
 202
 203 gint
 204 WriteZStream (ZStream *stream, guchar *buffer, gint length)
 205 {
 206         gint n;
 207         gint status;
 208         z_stream *zs;
 209
 210         if (stream == NULL || buffer == NULL || length < 0)
 211                 return ARGUMENT_ERROR;
 212
 213         if (stream->eof)
 214                 return IO_ERROR;
 215
 216         zs = stream->stream;
 217         zs->next_in = buffer;
 218         zs->avail_in = length;
 219         while (zs->avail_in > 0) {
 220                 if (zs->avail_out == 0) {
 221                         zs->next_out = stream->buffer;
 222                         zs->avail_out = BUFFER_SIZE;
 223                 }
 224                 status = deflate (stream->stream, Z_NO_FLUSH);
 225                 if (status != Z_OK && status != Z_STREAM_END)
 226                         return status;
 227
 228                 if (zs->avail_out == 0) {
 229                         n = write_to_managed (stream);
 230                         if (n < 0)
 231                                 return n;
 232                 }
 233         }
 234         return length;
 235 }
 236