libbase/IOChannel.cpp

   1 // IOChannel.cpp - a virtual IO channel, for Gnash
   2 //
   3 //   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Free Software
   4 //   Foundation, Inc
   5 //
   6 // This program is free software; you can redistribute it and/or modify
   7 // it under the terms of the GNU General Public License as published by
   8 // the Free Software Foundation; either version 3 of the License, or
   9 // (at your option) any later version.
  10 //
  11 // This program is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15 //
  16 // You should have received a copy of the GNU General Public License
  17 // along with this program; if not, write to the Free Software
  18 // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19 //
  20
  21
  22 #include "IOChannel.h"
  23
  24 #include <boost/static_assert.hpp>
  25
  26 namespace gnash
  27 {
  28
  29 boost::uint32_t
  30 IOChannel::read_le32()
  31 {
  32     // read_byte() is boost::uint8_t, so no masks with 0xff are required.
  33     boost::uint32_t result = static_cast<boost::uint32_t>(read_byte());
  34     result |= static_cast<boost::uint32_t>(read_byte()) << 8;
  35     result |= static_cast<boost::uint32_t>(read_byte()) << 16;
  36     result |= static_cast<boost::uint32_t>(read_byte()) << 24;
  37     return(result);
  38 }
  39
  40 boost::uint16_t
  41 IOChannel::read_le16()
  42 {
  43     boost::uint16_t result = static_cast<boost::uint16_t>(read_byte());
  44     result |= static_cast<boost::uint16_t>(read_byte()) << 8;
  45     return(result);
  46 }
  47
  48 int
  49 IOChannel::read_string(char* dst, int max_length)
  50 {
  51     int i = 0;
  52     while (i<max_length)
  53     {
  54         dst[i] = read_byte();
  55         if (dst[i]=='\0') return i;
  56         i++;
  57     }
  58
  59     dst[max_length - 1] = '\0';    // force termination.
  60
  61     return -1;
  62 }
  63
  64 float
  65 IOChannel::read_float32()
  66 {
  67     union {
  68         float    f;
  69         boost::uint32_t    i;
  70     } u;
  71
  72     BOOST_STATIC_ASSERT(sizeof(u) == sizeof(u.i));
  73
  74     u.i = read_le32();
  75     return u.f;
  76 }
  77
  78 boost::uint8_t
  79 IOChannel::read_byte()
  80 {
  81     boost::uint8_t u;
  82     if ( read(&u, 1) == -1 )
  83     {
  84         throw IOException("Could not read a single byte from input");
  85     }
  86     return u;
  87 }
  88
  89 std::streamsize
  90 IOChannel::write(const void* /*src*/, std::streamsize /*num*/)
  91 {
  92     throw IOException("This IOChannel implementation doesn't support output");
  93 }
  94
  95 } // namespace gnash