mngfile.cpp

   1 /*
   2  *  mngfile.cpp
   3  *  openc2e
   4  *
   5  *  Created by Alyssa Milburn on Tue 16 Nov 2004.
   6  *  Copyright (c) 2004-2006 Alyssa Milburn. All rights reserved.
   7  *
   8  *  This library is free software; you can redistribute it and/or
   9  *  modify it under the terms of the GNU Lesser General Public
  10  *  License as published by the Free Software Foundation; either
  11  *  version 2 of the License, or (at your option) any later version.
  12  *
  13  *  This library is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  *  Lesser General Public License for more details.
  17  *
  18  */
  19 #include <assert.h>
  20 #include "endianlove.h"
  21 #include "exceptions.h"
  22 #include <stdio.h>
  23 #include "mngfile.h"
  24 #include <sys/mman.h>
  25 #include <math.h>
  26 #include <unistd.h>
  27 #include <errno.h>
  28 #include "lex.mng.h"
  29
  30 mngFlexLexer *mnglexer = NULL;
  31 MNGFile *g_mngfile = NULL;
  32 extern int mngparse(); // parser
  33
  34 void decryptbuf(char * buf, int len) {
  35         int i;
  36         unsigned char pad = 5;
  37         for(i = 0; i < len; i++) {
  38                 buf[i] ^= pad;
  39                 pad += 0xC1;
  40         }
  41 }
  42
  43 MNGFile::MNGFile(std::string n) {
  44         sampleno = 0;
  45
  46         name = n;
  47
  48         f = fopen(name.c_str(), "r");
  49         if(!f) {
  50                 throw MNGFileException("Can't open file", errno);
  51         }
  52
  53         // Hack to obtain the filesize
  54         fseek(f, 0, SEEK_END);
  55         filesize = ftell(f);
  56
  57         // mmap the data file
  58         map = (char *) mmap(0, filesize, PROT_READ, MAP_PRIVATE, fileno(f), 0);
  59         if(map == (void *) -1) {
  60                 throw MNGFileException("Can't mmap", errno);
  61         }
  62
  63         // Read metavariables from beginning of file
  64         numsamples = swapEndianLong(*((int *) map));
  65         scriptoffset = swapEndianLong(*(((int *) map) + 1));
  66         scriptend = swapEndianLong(*(((int *) map) + 3));
  67         scriptlength = scriptend - scriptoffset;
  68
  69         // read the samples
  70         for(int i = 0; i < numsamples; i++) {
  71                 // Sample offsets and lengths are stored in pairs after the initial 16 bytes
  72                 int position = swapEndianLong(*((int *) map + 3 + (2 * i)));
  73
  74                 // skip four bytes of the WAVE header, four of the FMT header,
  75                 // the FMT chunk and four of the DATA header
  76                 position += swapEndianLong(*(int *)(map + position)) + 8;
  77
  78                 int size = swapEndianLong(*((int *) (map + position)));
  79                 position += 4; // Skip the size field
  80
  81                 samples.push_back(std::make_pair(map + position, size));
  82         }
  83
  84         // now we have the samples, read and decode the MNG script
  85         script = (char *) malloc(scriptlength + 1);
  86         script[scriptlength] = 0;
  87         if(! script) throw MNGFileException("malloc failed", errno);
  88         memcpy(script, map + scriptoffset, scriptlength);
  89         decryptbuf(script, scriptlength);
  90
  91         std::istringstream tehscript(script);
  92         mngrestart(&tehscript);
  93         g_mngfile = this;
  94         mngparse();
  95         g_mngfile = 0;
  96
  97         processState *p = new processState(this);
  98         for (std::map<std::string, MNGEffectDecNode *>::iterator i = effects.begin(); i != effects.end(); i++)
  99                 (*i).second->postProcess(p);
 100         for (std::map<std::string, MNGTrackDecNode *>::iterator i = tracks.begin(); i != tracks.end(); i++)
 101                 (*i).second->postProcess(p);
 102         // don't call postProcess on variabledec!
 103         delete p;
 104 }
 105
 106 void MNGFile::enumerateSamples() {
 107         std::vector< std::pair< char *, int > >::iterator i;
 108         for(i = samples.begin(); i != samples.end(); i++) {
 109                 printf("Position: \"%p\" Length: %i\n", (void *)(*i).first, (*i).second);
 110                 // PlaySound((*i).second.first, (*i).second.second);
 111         }
 112 }
 113
 114
 115 MNGFile::~MNGFile() {
 116         free(script);
 117         munmap(map, filesize);
 118         fclose(f);
 119 }
 120
 121 void mngrestart(std::istream *is) {
 122         if (mnglexer)
 123                 delete mnglexer;
 124         mnglexer = new mngFlexLexer();
 125         mnglexer->yyrestart(is);
 126 }
 127
 128 void mngerror(char const *s) {
 129         throw creaturesException(s);
 130 }
 131
 132 /* vim: set noet: */