Merge pull request #12 from leiradel/master

added crc32 utility

utils/crc32.c

@@ -0,0 +1,46 @@
+/* gcc -O3 -o crc32 crc32.c -lz */
+
+#include <stdio.h>
+#include <zlib.h>
+#include <errno.h>
+#include <string.h>
+
+int main( int argc, const char* argv[] )
+{
+  if ( argc != 2 )
+  {
+    fprintf( stderr, "Usage: crc32 <filename>\n" );
+    return 1;
+  }
+  
+  FILE* file = fopen( argv[ 1 ], "rb" );
+  
+  if ( file )
+  {
+    uLong crc = crc32( 0L, Z_NULL, 0 );
+    
+    for ( ;; )
+    {
+      Bytef buffer[ 16384 ];
+      
+      int numread = fread( (void*)buffer, 1, sizeof( buffer ), file );
+      
+      if ( numread > 0 )
+      {
+        crc = crc32( crc, buffer, numread );
+      }
+      else
+      {
+        break;
+      }
+    }
+    
+    fclose( file );
+    
+    printf( "%08x\n", crc );
+    return 0;
+  }
+  
+  fprintf( stderr, "Error opening input file: %s\n", strerror( errno ) );
+  return 1;
+}