[Assorted-commits] SF.net SVN: assorted:[1252] cpp-commons/trunk/src

[<yan...@us...>]

Revision: 1252
          http://assorted.svn.sourceforge.net/assorted/?rev=1252&view=rev
Author:   yangzhang
Date:     2009-03-05 23:14:45 +0000 (Thu, 05 Mar 2009)

Log Message:
-----------
- accum returns residual count instead of bool
- added anchor, reset

Modified Paths:
--------------
    cpp-commons/trunk/src/commons/streamreader.h
    cpp-commons/trunk/src/test/streamreader.cc

Modified: cpp-commons/trunk/src/commons/streamreader.h
===================================================================
--- cpp-commons/trunk/src/commons/streamreader.h	2009-03-04 23:31:58 UTC (rev 1251)
+++ cpp-commons/trunk/src/commons/streamreader.h	2009-03-05 23:14:45 UTC (rev 1252)
@@ -48,7 +48,8 @@
         full_reader_(repeat_reader(reader_)),
         buf_(buf, bufsize),
         start_(buf),
-        end_(buf)
+        end_(buf),
+        anchor_(buf)
       {}
 
       stream_reader(boost::function<size_t(char*, size_t)> reader,
@@ -58,7 +59,8 @@
         full_reader_(full_reader),
         buf_(buf, bufsize),
         start_(buf),
-        end_(buf)
+        end_(buf),
+        anchor_(buf)
       {}
 
       /**
@@ -80,33 +82,47 @@
        * Manually update/adjust the pointers; useful after changing buf_.
        */
       void reset_range(char *start, char *end) {
-        start_ = start;
+        anchor_ = start_ = start;
         end_ = end;
       }
 
+      void set_anchor() { anchor_ = start_; }
+
+      /**
+       * Reset the pointers, emptying the buffer.
+       */
+      void reset() {
+        start_ = end_ = anchor_ = buf_.get();
+      }
+
       char *start() { return start_; }
       char *end() { return end_; }
+      char *anchor() { return anchor_; }
 
       /**
-       * Accumulate (but don't read/copy) the requested number of bytes.
+       * Accumulate (treat as read, but don't discard, and don't actually
+       * copy for reading) the requested number of bytes.  Returns the
+       * remaining number of requested bytes that couldn't be accumulated
+       * because we ran out of buffer space.
        */
-      bool accum(size_t req) {
+      size_t accum(size_t req) {
         while (unread() < req && rem() > 0) {
           size_t res = reader_(end_, rem());
           if (res == 0) throw eof_exception();
           end_ += res;
         }
         if (unread() < req) {
+          size_t ret = req - unread();
           start_ = end_;
-          return false;
+          return ret;
         } else {
           start_ += req;
-          return true;
+          return 0;
         }
       }
 
       /**
-       * Discard the requested number of bytes.
+       * Discard the requested number of bytes.  Disregards anchor.
        */
       void skip(size_t req) {
         if (unread() >= req) {
@@ -119,7 +135,7 @@
         // reading.  Skip over bytes that are immediately available...
         req -= unread();
         // ...and reset pointers to discard current buffer.
-        start_ = end_ = buf_.get();
+        reset();
 
         // Keep reading until we have enough.
         while (true) {
@@ -153,7 +169,7 @@
           managed_array<char> p(new char[req], true);
           memcpy(p.get(), start_, unread());
           full_reader_(p + unread(), req - unread());
-          start_ = end_ = buf_.get();
+          reset();
           return p;
         }
 
@@ -240,6 +256,11 @@
        * The end of the unconsumed range of bytes.
        */
       char *end_;
+
+      /**
+       * Do not discard bytes >= this.
+       */
+      char *anchor_;
   };
 
 }

Modified: cpp-commons/trunk/src/test/streamreader.cc
===================================================================
--- cpp-commons/trunk/src/test/streamreader.cc	2009-03-04 23:31:58 UTC (rev 1251)
+++ cpp-commons/trunk/src/test/streamreader.cc	2009-03-05 23:14:45 UTC (rev 1252)
@@ -52,13 +52,13 @@
     {
       array<char> rbuf(9);
       stream_reader r(rfn(chunklen, src), rbuf.get(), rbuf.size());
-      EXPECT_TRUE(r.accum(sizeof(int)));
-      EXPECT_TRUE(r.accum(sizeof(int)));
-      EXPECT_FALSE(r.accum(sizeof(int)));
+      EXPECT_EQ(0, r.accum(sizeof(int)));
+      EXPECT_EQ(0, r.accum(sizeof(int)));
+      EXPECT_EQ(3, r.accum(sizeof(int)));
       r.shift();
-      EXPECT_TRUE(r.accum(sizeof(int)));
-      EXPECT_TRUE(r.accum(sizeof(int)));
-      EXPECT_FALSE(r.accum(sizeof(int)));
+      EXPECT_EQ(0, r.accum(sizeof(int)));
+      EXPECT_EQ(0, r.accum(sizeof(int)));
+      EXPECT_EQ(3, r.accum(sizeof(int)));
     }
   }
 }


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