fix magic so that it can detect binary file

src/io/io.cpp

@@ -2,6 +2,7 @@
 #define _CRT_SECURE_NO_DEPRECATE
 #include <string>
 #include "./io.h"
+#include "../utils/io.h"
 #include "../utils/utils.h"
 #include "simple_dmatrix-inl.hpp"
 // implements data loads using dmatrix simple for now
@@ -9,6 +10,19 @@
 namespace xgboost {
 namespace io {
 DataMatrix* LoadDataMatrix(const char *fname, bool silent, bool savebuffer) {
+  int magic;
+  utils::FileStream fs(utils::FopenCheck(fname, "rb"));
+  utils::Check(fs.Read(&magic, sizeof(magic)) != 0, "invalid input file format");
+  fs.Seek(0);
+
+  if (magic == DMatrixSimple::kMagic) { 
+    DMatrixSimple *dmat = new DMatrixSimple();
+    dmat->LoadBinary(fs, silent, fname);
+    fs.Close();
+    return dmat;
+  } 
+  fs.Close();
+ 
   DMatrixSimple *dmat = new DMatrixSimple();
   dmat->CacheLoad(fname, silent, savebuffer);
   return dmat;

src/io/simple_dmatrix-inl.hpp

@@ -128,6 +128,17 @@ class DMatrixSimple : public DataMatrix {
     FILE *fp = fopen64(fname, "rb");
     if (fp == NULL) return false;
     utils::FileStream fs(fp);
+    this->LoadBinary(fs, silent, fname);
+    fs.Close();
+    return true;
+  }
+  /*!
+   * \brief load from binary stream
+   * \param fs input file stream
+   * \param silent whether print information during loading
+   * \param fname file name, used to print message
+   */
+  inline void LoadBinary(utils::IStream &fs, bool silent = false, const char *fname = NULL) {
     int magic;
     utils::Check(fs.Read(&magic, sizeof(magic)) != 0, "invalid input file format");
     utils::Check(magic == kMagic, "invalid format,magic number mismatch");
@@ -135,16 +146,19 @@ class DMatrixSimple : public DataMatrix {
     info.LoadBinary(fs);
     FMatrixS::LoadBinary(fs, &row_ptr_, &row_data_);
     fmat.LoadColAccess(fs);
-    fs.Close();
 
     if (!silent) {
-      printf("%lux%lu matrix with %lu entries is loaded from %s\n",
-             info.num_row(), info.num_col(), row_data_.size(), fname);
+      printf("%lux%lu matrix with %lu entries is loaded",
+             info.num_row(), info.num_col(), row_data_.size());
+      if (fname != NULL) {
+        printf(" from %s\n", fname);
+      } else {
+        printf("\n");
+      }
       if (info.group_ptr.size() != 0) {
         printf("data contains %u groups\n", (unsigned)info.group_ptr.size()-1);
       }
     }
-    return true;
   }
   /*!
    * \brief save to binary file

src/utils/io.h

@@ -102,6 +102,9 @@ class FileStream : public IStream {
   virtual void Write(const void *ptr, size_t size) {
     fwrite(ptr, size, 1, fp);
   }
+  inline void Seek(size_t pos) {
+    fseek(fp, 0, SEEK_SET);
+  }
   inline void Close(void) {
     fclose(fp);
   }

wrapper/xgboost.py

@@ -45,7 +45,7 @@ class DMatrix:
             return
         if isinstance(data, str):
             self.handle = ctypes.c_void_p(
-                xglib.XGDMatrixCreateFromFile(ctypes.c_char_p(data.encode('utf-8')), 1))
+                xglib.XGDMatrixCreateFromFile(ctypes.c_char_p(data.encode('utf-8')), 0))
         elif isinstance(data, scp.csr_matrix):
             self.__init_from_csr(data)
         elif isinstance(data, numpy.ndarray) and len(data.shape) == 2: