source/libs/poppler/poppler-0.30.0/poppler/FlateStream.cc

   1 //========================================================================
   2 //
   3 // FlateStream.cc
   4 //
   5 // Copyright (C) 2005, Jeff Muizelaar <jeff@infidigm.net>
   6 // Copyright (C) 2010, Albert Astals Cid <aacid@kde.org>
   7 //
   8 // This file is under the GPLv2 or later license
   9 //
  10 //========================================================================
  11 #include "FlateStream.h"
  12 FlateStream::FlateStream(Stream *strA, int predictor, int columns, int colors, int bits) :
  13   FilterStream(strA)
  14 {
  15   if (predictor != 1) {
  16     pred = new StreamPredictor(this, predictor, columns, colors, bits);
  17   } else {
  18     pred = NULL;
  19   }
  20   out_pos = 0;
  21   memset(&d_stream, 0, sizeof(d_stream));
  22   inflateInit(&d_stream);
  23 }
  24
  25 FlateStream::~FlateStream() {
  26   inflateEnd(&d_stream);
  27   delete pred;
  28   delete str;
  29 }
  30
  31 void FlateStream::reset() {
  32   //FIXME: what are the semantics of reset?
  33   //i.e. how much intialization has to happen in the constructor?
  34
  35   /* reinitialize zlib */
  36   inflateEnd(&d_stream);
  37   memset(&d_stream, 0, sizeof(d_stream));
  38   inflateInit(&d_stream);
  39
  40   str->reset();
  41   d_stream.avail_in = 0;
  42   status = Z_OK;
  43   out_pos = 0;
  44   out_buf_len = 0;
  45 }
  46
  47 int FlateStream::getRawChar() {
  48   return doGetRawChar();
  49 }
  50
  51 void FlateStream::getRawChars(int nChars, int *buffer) {
  52   for (int i = 0; i < nChars; ++i)
  53     buffer[i] = doGetRawChar();
  54 }
  55
  56 int FlateStream::getChar() {
  57   if (pred)
  58     return pred->getChar();
  59   else
  60     return getRawChar();
  61 }
  62
  63 int FlateStream::lookChar() {
  64   if (pred)
  65     return pred->lookChar();
  66
  67   if (fill_buffer())
  68     return EOF;
  69
  70   return out_buf[out_pos];
  71 }
  72
  73 int FlateStream::fill_buffer() {
  74   /* only fill the buffer if it has all been used */
  75   if (out_pos >= out_buf_len) {
  76     /* check if the flatestream has been exhausted */
  77     if (status == Z_STREAM_END) {
  78       return -1;
  79     }
  80
  81     /* set to the begining of out_buf */
  82     d_stream.avail_out = sizeof(out_buf);
  83     d_stream.next_out = out_buf;
  84     out_pos = 0;
  85
  86     while (1) {
  87       /* buffer is empty so we need to fill it */
  88       if (d_stream.avail_in == 0) {
  89         int c;
  90         /* read from the source stream */
  91         while (d_stream.avail_in < sizeof(in_buf) && (c = str->getChar()) != EOF) {
  92           in_buf[d_stream.avail_in++] = c;
  93         }
  94         d_stream.next_in = in_buf;
  95       }
  96
  97       /* keep decompressing until we can't anymore */
  98       if (d_stream.avail_out == 0 || d_stream.avail_in == 0 || (status != Z_OK && status != Z_BUF_ERROR))
  99         break;
 100       status = inflate(&d_stream, Z_SYNC_FLUSH);
 101     }
 102
 103     out_buf_len = sizeof(out_buf) - d_stream.avail_out;
 104     if (status != Z_OK && status != Z_STREAM_END)
 105       return -1;
 106     if (!out_buf_len)
 107       return -1;
 108   }
 109
 110   return 0;
 111 }
 112
 113 GooString *FlateStream::getPSFilter(int psLevel, const char *indent) {
 114   GooString *s;
 115
 116   if (psLevel < 3 || pred) {
 117     return NULL;
 118   }
 119   if (!(s = str->getPSFilter(psLevel, indent))) {
 120     return NULL;
 121   }
 122   s->append(indent)->append("<< >> /FlateDecode filter\n");
 123   return s;
 124 }
 125
 126 GBool FlateStream::isBinary(GBool last) {
 127   return str->isBinary(gTrue);
 128 }