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, unsigned int nitems, unsigned int 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         result->stream->next_out = result->buffer;
  94         result->stream->avail_out = BUFFER_SIZE;
  95         return result;
  96 }
  97
  98 gint
  99 CloseZStream (ZStream *zstream)
 100 {
 101         gint status;
 102         gint flush_status;
 103
 104         if (zstream == NULL)
 105                 return ARGUMENT_ERROR;
 106
 107         status = 0;
 108         if (zstream->compress) {
 109                 if (zstream->stream->total_in > 0) {
 110                         do {
 111                                 status = deflate (zstream->stream, Z_FINISH);
 112                                 flush_status = flush_internal (zstream, TRUE);
 113                         } while (status == Z_OK); /* We want Z_STREAM_END or error here here */
 114                         if (status == Z_STREAM_END)
 115                                 status = flush_status;
 116                 }
 117                 deflateEnd (zstream->stream);
 118         } else {
 119                 inflateEnd (zstream->stream);
 120         }
 121         g_free (zstream->buffer);
 122         g_free (zstream->stream);
 123         memset (zstream, 0, sizeof (ZStream));
 124         g_free (zstream);
 125         return status;
 126 }
 127
 128 static gint
 129 write_to_managed (ZStream *stream)
 130 {
 131         gint n;
 132         z_stream *zs;
 133
 134         zs = stream->stream;
 135         if (zs->avail_out != BUFFER_SIZE) {
 136                 n = stream->func (stream->buffer, BUFFER_SIZE - zs->avail_out, stream->gchandle);
 137                 zs->next_out = stream->buffer;
 138                 zs->avail_out = BUFFER_SIZE;
 139                 if (n < 0)
 140                         return IO_ERROR;
 141         }
 142         return 0;
 143 }
 144
 145 static gint
 146 flush_internal (ZStream *stream, gboolean is_final)
 147 {
 148         gint status;
 149
 150         if (!stream->compress)
 151                 return 0;
 152
 153         if (!is_final && stream->stream->avail_in != 0) {
 154                 status = deflate (stream->stream, Z_PARTIAL_FLUSH);
 155                 if (status != Z_OK && status != Z_STREAM_END)
 156                         return status;
 157         }
 158         return write_to_managed (stream);
 159 }
 160
 161 gint
 162 Flush (ZStream *stream)
 163 {
 164         return flush_internal (stream, FALSE);
 165 }
 166
 167 gint
 168 ReadZStream (ZStream *stream, guchar *buffer, gint length)
 169 {
 170         gint n;
 171         gint status;
 172         z_stream *zs;
 173
 174         if (stream == NULL || buffer == NULL || length < 0)
 175                 return ARGUMENT_ERROR;
 176
 177         if (stream->eof)
 178                 return 0;
 179
 180         zs = stream->stream;
 181         zs->next_out = buffer;
 182         zs->avail_out = length;
 183         while (zs->avail_out > 0) {
 184                 if (zs->avail_in == 0) {
 185                         n = stream->func (stream->buffer, BUFFER_SIZE, stream->gchandle);
 186                         if (n <= 0) {
 187                                 stream->eof = TRUE;
 188                         }
 189                         zs->next_in = stream->buffer;
 190                         zs->avail_in = n;
 191                 }
 192
 193                 if (zs->avail_in == 0 && zs->total_in == 0)
 194                         return Z_STREAM_END;
 195
 196                 status = inflate (stream->stream, Z_SYNC_FLUSH);
 197                 if (status == Z_STREAM_END) {
 198                         stream->eof = TRUE;
 199                         break;
 200                 } else if (status != Z_OK) {
 201                         return status;
 202                 }
 203         }
 204         return length - zs->avail_out;
 205 }
 206
 207 gint
 208 WriteZStream (ZStream *stream, guchar *buffer, gint length)
 209 {
 210         gint n;
 211         gint status;
 212         z_stream *zs;
 213
 214         if (stream == NULL || buffer == NULL || length < 0)
 215                 return ARGUMENT_ERROR;
 216
 217         if (stream->eof)
 218                 return IO_ERROR;
 219
 220         zs = stream->stream;
 221         zs->next_in = buffer;
 222         zs->avail_in = length;
 223         while (zs->avail_in > 0) {
 224                 if (zs->avail_out == 0) {
 225                         zs->next_out = stream->buffer;
 226                         zs->avail_out = BUFFER_SIZE;
 227                 }
 228                 status = deflate (stream->stream, Z_NO_FLUSH);
 229                 if (status != Z_OK && status != Z_STREAM_END)
 230                         return status;
 231
 232                 if (zs->avail_out == 0) {
 233                         n = write_to_managed (stream);
 234                         if (n < 0)
 235                                 return n;
 236                 }
 237         }
 238         return length;
 239 }
 240