Merge branch 'stlTypeCheck' into 'master'

Stl type check

implemented the suggested changes from #24 by checking stl files for the keyword solid instead of computing binary file size.
closes #24 

See merge request !83

Doc/changelog.docu

@@ -13,13 +13,18 @@
 <ul>
 <li>Fixed type pun warning with gcc-6</li>
 <li>Fixed incorrect type of hash function for boost causing a warning with clang</li>
-</li>
+</ul>
+
+<b>IO</b>
+<ul>
+<li>STL Reader: Identify stl files containing solid keyword as ASCII type</li>
+</ul>
 
 
 <b>General</b>
 <ul>
 <li>Fixed undefined MSVC macro warning (Thanks to Xan for the patch)</li> 
-</li>
+</ul>
 
 <b>Build System</b>
 <ul>

src/OpenMesh/Core/IO/reader/STLReader.cc

@@ -55,12 +55,20 @@
 
 #include <float.h>
 #include <fstream>
+#include <cstring>
 
 // OpenMesh
 #include <OpenMesh/Core/IO/BinaryHelper.hh>
 #include <OpenMesh/Core/IO/reader/STLReader.hh>
 #include <OpenMesh/Core/IO/IOManager.hh>
 
+//comppare strings crossplatform ignorign case
+#ifdef _WIN32
+  #define strnicmp _strnicmp
+#else
+  #define strnicmp strncasecmp
+#endif
+
 
 //=== NAMESPACES ==============================================================
 
@@ -447,15 +455,38 @@ _STLReader_::STL_Type
 _STLReader_::
 check_stl_type(const std::string& _filename) const
 {
-  // assume it's binary stl, then file size is known from #triangles
-  // if size matches, it's really binary
-
 
    // open file
+   std::ifstream ifs (_filename.c_str(), std::ifstream::binary);
+   if(!ifs.good())
+   {
+     omerr() << "could not open file" << _filename << std::endl;
+     return NONE;
+   }
+
+   //find first non whitespace character
+   std::string line = "";
+   std::size_t firstChar;
+   while(line.empty() && ifs.good())
+   {
+     std::getline(ifs,line);
+     firstChar = line.find_first_not_of("\t ");
+   }
+
+   //check for ascii keyword solid
+   if(strnicmp("solid",&line[firstChar],5) == 0)
+   {
+     return STLA;
+   }
+   ifs.close();
+
+   //if the file does not start with solid it is probably STLB
+   //check the file size to verify it.
+
+   //open the file
    FILE* in = fopen(_filename.c_str(), "rb");
    if (!in) return NONE;
 
-
    // determine endian mode
    union { unsigned int i; unsigned char c[4]; } endian_test;
    endian_test.i = 1;
@@ -471,7 +502,6 @@ check_stl_type(const std::string& _filename) const
    // compute file size from nT
    size_t binary_size = 84 + nT*50;
 
-
    // get actual file size
    size_t file_size(0);
    rewind(in);
@@ -479,9 +509,8 @@ check_stl_type(const std::string& _filename) const
      file_size += fread(dummy, 1, 100, in);
    fclose(in);
 
-
    // if sizes match -> it's STLB
-  return (binary_size == file_size ? STLB : STLA);
+      return (binary_size == file_size ? STLB : NONE);
 }