Merged branch 'dev_native' into lm_sla_supports_auto

Added igl library files

src/igl/guess_extension.cpp

@@ -0,0 +1,106 @@
+#include "guess_extension.h"
+
+#include <string.h>
+
+#include "is_stl.h"
+#include "ply.h"
+
+IGL_INLINE void igl::guess_extension(FILE * fp, std::string & guess)
+{
+  const auto is_off = [](FILE * fp)-> bool
+  {
+    char header[1000];
+    const std::string OFF("OFF");
+    const std::string NOFF("NOFF");
+    const std::string COFF("COFF");
+    bool f = (fscanf(fp,"%s\n",header)==1 && (
+        std::string(header).compare(0, OFF.length(), OFF)==0 ||
+        std::string(header).compare(0, COFF.length(), COFF)==0 ||
+        std::string(header).compare(0,NOFF.length(),NOFF)==0));
+    rewind(fp);
+    return f;
+  };
+  const auto is_ply = [](FILE * ply_file) -> bool
+  {
+    int nelems;
+    char ** elem_names;
+    igl::ply::PlyFile * in_ply = igl::ply::ply_read(ply_file,&nelems,&elem_names);
+    if(in_ply==NULL)
+    {
+      return false;
+    }
+    free(in_ply);
+    rewind(ply_file);
+    return true;
+  };
+  const auto is_wrl = [](FILE * wrl_file)->bool
+  {
+    bool still_comments = true;
+    char line[1000];
+    std::string needle("point [");
+    std::string haystack;
+    while(still_comments)
+    {
+      if(fgets(line,1000,wrl_file) == NULL)
+      {
+        rewind(wrl_file);
+        return false;
+      }
+      haystack = std::string(line);
+      still_comments = std::string::npos == haystack.find(needle);
+    }
+    rewind(wrl_file);
+    return true;
+  };
+  const auto is_mesh = [](FILE * mesh_file )->bool
+  {
+    char line[2048];
+    // eat comments at beginning of file
+    bool still_comments= true;
+    while(still_comments)
+    {
+      if(fgets(line,2048,mesh_file) == NULL)
+      {
+        rewind(mesh_file);
+        return false;
+      }
+      still_comments = (line[0] == '#' || line[0] == '\n');
+    }
+    char str[2048];
+    sscanf(line," %s",str);
+    // check that first word is MeshVersionFormatted
+    if(0!=strcmp(str,"MeshVersionFormatted"))
+    {
+      rewind(mesh_file);
+      return false;
+    }
+    rewind(mesh_file);
+    return true;
+  };
+  guess = "obj";
+  if(is_mesh(fp))
+  {
+    guess = "mesh";
+  }else if(is_off(fp))
+  {
+    guess = "off";
+  }else if(is_ply(fp))
+  {
+    guess = "ply";
+  }else if(igl::is_stl(fp))
+  {
+    guess = "stl";
+  }else if(is_wrl(fp))
+  {
+    guess = "wrl";
+  }
+  // else obj
+  rewind(fp);
+}
+
+IGL_INLINE std::string igl::guess_extension(FILE * fp)
+{
+  std::string guess;
+  guess_extension(fp,guess);
+  return guess;
+}