font2png, iffexplore: Misc. cleanup

font2png.cc

@@ -31,49 +31,28 @@ struct Font {
 struct FontHeader { // little endian
   uint32_t unknown1; // (always)? "1.\0\0"
   uint32_t entries;
-  uint32_t charWidth;
+  uint32_t charHeight;
   uint8_t bgColor;
   char unknown3[3];
 } __attribute__((__packed__));
 
 Font parseFont(FILE* file, size_t length)
 {
-  // if (fseeko(file, 16, SEEK_SET) != 0) {
+  if (length < sizeof(FontHeader))
-  //   throw POSIXException(errno, "Could not seek");
+    throw FormatException{"File smaller than header"};
-  // }
-
-  // uint32_t data, last_data = 0;
-  // int last_diff = -1, count = 0;
-  // size_t pos = 16;
-  // while (pos < length) {
-  //   if (fread(&data, 4, 1, file) != 1) {
-  //     if (feof(file))
-  // 	throw Exception{"Unexpected EOF"};
-  //     throw POSIXException{errno, "Could not read"};
-  //   }
-
-  //   if ((last_diff == -1) ||
-  // 	(data-last_data == last_diff)) {
-  //     ++count;
-  //     last_diff = data-last_data;
-  //     //      printf("%.8x\n", data);
-  //   } else {
-  //     if ((count > 1) && last_diff )
-  // 	printf("%d times diff %d\n", count, last_diff);
-  //     count = 0;
-  //     last_diff = -1;
-  //   }
-  //   last_data = data;
-  //   pos += 4;
-  // }
   
   FontHeader header;
   if (fread(&header, sizeof(FontHeader), 1, file) != 1)
       throw POSIXException{errno, "Could not read"};
 
+  if (header.unknown1 != 0x00002E31)
+    throw FormatException{"Not a font?"};
+  
   const unsigned index_start = sizeof(FontHeader);
   const unsigned index_end = index_start+4*header.entries;
-  const unsigned char_width = header.charWidth;
+
+  if (index_end > length)
+    throw Exception{"Index table exceeds file length"};
   
   std::vector<uint32_t> indices;
   for (unsigned i = index_start;i < index_end;i+=4) {
@@ -87,9 +66,12 @@ Font parseFont(FILE* file, size_t length)
   printf("Index range %u .. %u\n",
 	 *minmax.first, *minmax.second);
 
+  if (*minmax.second > length)
+    throw FormatException{"Index exceeds file length"};
+  
   Font ret;
   ret.numChars = header.entries;
-  ret.charHeight = char_width;
+  ret.charHeight = header.charHeight;
   ret.maxCharWidth = 0;
   ret.bgColor = header.bgColor;
   for (auto const& index : indices) {
@@ -101,19 +83,22 @@ Font parseFont(FILE* file, size_t length)
       throw POSIXException{errno, "Could not read"};
 
     if (!len) {
-      ret.chars.push_back(Image{});
+      ret.chars.push_back(Image{0, 0, {}});
       continue;
     }
 
+    if (index+4+len*header.charHeight > length)
+      throw FormatException{"Glyph data exceeds file length"};
+    
     Image chr;
-    chr.height = char_width;
+    chr.height = header.charHeight;
     chr.width = len;
-    chr.data.resize(char_width*len);
+    chr.data.resize(chr.height*chr.width);
 
     if (chr.width > ret.maxCharWidth)
       ret.maxCharWidth = chr.width;
     
-    if (fread(chr.data.data(), len*char_width, 1, file) != 1)
+    if (fread(chr.data.data(), chr.height*chr.width, 1, file) != 1)
       throw POSIXException{errno, "Could not read"};
 
     ret.chars.push_back(chr);

iffexplore.cc

@@ -13,10 +13,10 @@
 
 struct ChunkHeader {
   char typeID[4];
-  uint32_t length;
+  uint32_t length; // big endian!!
-};
+} __attribute__((__packed__));
 
-void parseBlob(FILE *iffFile, off_t start, off_t length, char name[4], unsigned level)
+void parseBlob(FILE *iffFile, off_t start, off_t length, char name[4], unsigned level, bool dump = false)
 {
   static unsigned count = 0;
   
@@ -74,6 +74,7 @@ void parseBlob(FILE *iffFile, off_t start, off_t length, char name[4], unsigned
   filename.append(std::to_string(count) + "-");
   filename.append(name, 4);
 
+  if (dump) {
     FILEUPtr outFile{fopen(filename.c_str(), "wb")};
     if (!outFile)
       throw POSIXException{errno, "Could not open " + filename};
@@ -84,6 +85,11 @@ void parseBlob(FILE *iffFile, off_t start, off_t length, char name[4], unsigned
   
     if (fwrite(buf.data(), length, 1, outFile.get()) != 1)
       throw POSIXException{errno, "Could not write data"};
+  } else {
+    for (unsigned i = 0;i < level;++i)
+      putchar('\t');
+    printf("BLOB  of length %ld (0x%lx)\n", length, length);
+  }
 
   ++count;
 }
@@ -97,6 +103,10 @@ void parseChunk(FILE* iffFile, off_t start, off_t length, unsigned level = 0)
       throw POSIXException(errno, "Could not seek");
     }
 
+    // pos < length due to loop condition, cast of difference to unsigned is OK
+    if (static_cast<unsigned>(length-pos) < sizeof(ChunkHeader))
+      throw FormatException{"Remaining size < header size"};
+    
     ChunkHeader header;
     
     if (fread(&header, sizeof(ChunkHeader), 1, iffFile) != 1) {
@@ -109,11 +119,10 @@ void parseChunk(FILE* iffFile, off_t start, off_t length, unsigned level = 0)
     for (unsigned i = 0;i < level;++i)
       putchar('\t');
     printf("Type: %.4s, Length: %u (0x%x)", header.typeID, header.length, header.length);
-    if (memcmp(header.typeID, "FORM", 4) == 0) {
+    if (header.length > (length-(pos+8)))
-      if (header.length > (length-(pos+8))) {
       throw FormatException{"Length in header > remaining parent size"};
-      }
     
+    if (memcmp(header.typeID, "FORM", 4) == 0) {
       char subType[4];
       if (fread(&subType, 4, 1, iffFile) != 1) {
 	throw POSIXException(errno, "Could not read form subtype");
@@ -126,10 +135,9 @@ void parseChunk(FILE* iffFile, off_t start, off_t length, unsigned level = 0)
       parseBlob(iffFile, start+pos+8, header.length, header.typeID, level+1);
     }
      
-    if (header.length%2 != 0)
-      pos += 1;
-      
     pos += header.length+8;
+    if (pos%2 != 0)
+      ++pos;
   }
 }