core/fasta.{h,cpp}: getPos(), number of characters read

Note that input->tellg() was not working (not compatible with igzstream ?)

algo/core/fasta.cpp

@@ -133,11 +133,16 @@ OnlineFasta::~OnlineFasta() {
 }
 
 void OnlineFasta::init() {
+  char_nb = 0;
   line_nb = 0;
   line = getInterestingLine();
   current.seq = NULL;
 }
 
+unsigned long long OnlineFasta::getPos() {
+  return char_nb;
+}
+
 size_t OnlineFasta::getLineNb() {
   return line_nb;
 }
@@ -226,6 +231,7 @@ string OnlineFasta::getInterestingLine(int state) {
   string line;
   while (line.length() == 0 && hasNext() && getline(*input, line)) {
     line_nb++;
+    char_nb += line.length() + 1;
     remove_trailing_whitespaces(line);
 
     if (line.length() && line[0] == '#' && state != FASTX_FASTQ_SEP)

algo/core/fasta.h

@@ -91,6 +91,7 @@ class OnlineFasta {
   string line;
   bool input_allocated;
   size_t line_nb;
+  unsigned long long char_nb;
 
  public:
 
@@ -113,7 +114,12 @@ class OnlineFasta {
               int extract_field=0, string extract_separator="|");
 
   ~OnlineFasta();
-  
+
+  /**
+   * @return the position in the file
+   */
+  unsigned long long getPos();
+
   /**
    * @return the current line number
    */