Created std::istream/ostream wrapper + test.

stream/clients/io_stream.hpp

@@ -0,0 +1,177 @@
+#ifndef MANGLE_STREAM_IOSTREAM_H
+#define MANGLE_STREAM_IOSTREAM_H
+
+#include <assert.h>
+#include "../stream.hpp"
+#include <iostream>
+#include <vector>
+
+// This seems to work (TODO: test)
+#ifndef EOF
+#define EOF -1
+#endif
+
+namespace Mangle {
+namespace Stream {
+
+  /** This file contains classes for wrapping an std::istream or
+      std::ostream around a Mangle::Stream. Not to be confused with
+      servers/std_(o)stream.hpp, which do the opposite (wrap a
+      Mangle::Stream around an std::istream/ostream.)
+
+      This allows you to use Mangle streams in places that require std
+      streams. The std::iostream interface is horrible and NOT
+      designed for easy subclassing. Defining your custom streams as
+      Mangle streams and then wrapping them here will usually be much
+      easier.
+  */
+  class IOStreamBuffer : public std::streambuf
+  {
+    StreamPtr client;
+    std::vector<char> ibuf, obuf;
+
+  public:
+    IOStreamBuffer(StreamPtr strm) : client(strm)
+    {
+      // Set up input buffer
+      setg(NULL,NULL,NULL);
+      if(client->isReadable)
+        {
+          if(client->hasPtr)
+            {
+              assert(client->hasSize);
+
+              // If the client supports direct pointer reading, then
+              // this is really easy. No internal buffer is needed.
+              char *ptr = (char*) client->getPtr();
+
+              // Set up the entire file as the input buffer
+              setg(ptr,ptr,ptr+client->size());
+            }
+          else
+            {
+              // We need to do some manual slave labor. Set up an
+              // empty input buffer and let underflow() handle it.
+              ibuf.resize(1024);
+            }
+        }
+
+      // Only create output buffer if the stream is writable
+      if(client->isWritable)
+        {
+          obuf.resize(1024);
+          /* Set beginning and end pointers, tells streambuf to write
+             to this area and call overflow() when it's full.
+
+             Several examples use size-1, but the documentation for
+             streambuf clearly states that the end pointers is just
+             _past_ the last accessible position.
+          */
+          char *beg = &obuf[0];
+          setp(beg, beg+obuf.size());
+        }
+      else
+        // Writing not permitted
+        setp(NULL, NULL);
+    }
+
+    /* Underflow is called when there is no more info to read in the
+       input buffer. We need to refill ibuf with data (if any), and
+       set up the internal pointers with setg() to reflect the new
+       state.
+    */
+    int underflow()
+    {
+      assert(client->isReadable);
+
+      // If we've exhausted a pointer stream, then there's no more to
+      // be had.
+      if(client->hasPtr)
+        return EOF;
+
+      // Read some more data
+      assert(ibuf.size());
+      char *iptr = &ibuf[0];
+      size_t read = client->read(iptr, ibuf.size());
+
+      // If we're out of data, then EOF
+      if(read == 0)
+        return EOF;
+
+      // Otherwise, set up input buffer
+      setg(iptr, iptr, iptr+read);
+
+      // Return the first char
+      return *((unsigned char*)iptr);
+    }
+
+    /* Sync means to flush (write) all current data to the output
+       stream. It will also set up the entire output buffer to be
+       usable again.
+     */
+    int sync()
+    {
+      assert(client->isWritable);
+      assert(obuf.size() > 0);
+
+      // Get the number of bytes that streambuf wants us to write
+      int num = pptr() - pbase();
+      assert(num >= 0);
+
+      // Nothing to do
+      if(num == 0) return 0;
+
+      if((int)client->write(pbase(), num) != num)
+        return -1;
+
+      // Reset output buffer pointers
+      char *beg = &obuf[0];
+      setp(beg, beg+obuf.size());
+
+      return 0;
+    }
+
+    int overflow(int c=EOF)
+    {
+      // First, write all existing data
+      if(sync()) return EOF;
+
+      // Put the requested character in the output
+      if(c != EOF)
+        {
+          *pptr() = c;
+          pbump(1);
+        }
+
+      return 0;
+    }
+  };
+
+  class MangleIStream : public std::istream
+  {
+    IOStreamBuffer buf;
+  public:
+    MangleIStream(StreamPtr inp)
+      : std::istream(&buf)
+      , buf(inp)
+    {
+      assert(inp->isReadable);
+    }
+  };
+
+  class MangleOStream : public std::ostream
+  {
+    IOStreamBuffer buf;
+  public:
+    MangleOStream(StreamPtr inp)
+      : std::ostream(&buf)
+      , buf(inp)
+    {
+      assert(inp->isWritable);
+    }
+
+    ~MangleOStream() { flush(); }
+  };
+
+}} // namespaces
+#endif

stream/servers/std_ostream.hpp

@@ -25,11 +25,7 @@ class StdOStream : public Stream
     hasPosition = true;
     hasSize = true;
     isWritable = true;
-  }
-
-  size_t read(void*,size_t)
-  {
-    assert(0&&"reading not supported by StdOStream");
+    isReadable = false;
   }
 
   size_t write(const void* buf, size_t len)

stream/stream.hpp

@@ -24,28 +24,38 @@ class Stream
   bool hasSize;
 
   /// If true, write() works. Writing through pointer operations is
-  /// not supported.
+  /// not (yet) supported.
   bool isWritable;
 
+  /// If true, read() and eof() works.
+  bool isReadable;
+
   /// If true, the getPtr() functions work
   bool hasPtr;
 
-  /// Initialize all bools to false by default
+  /// Initialize all bools to false by default, except isReadable.
   Stream() :
     isSeekable(false), hasPosition(false), hasSize(false),
-    isWritable(false), hasPtr(false) {}
+    isWritable(false), isReadable(true), hasPtr(false) {}
 
   /// Virtual destructor
   virtual ~Stream() {}
 
   /** Read a given number of bytes from the stream. Returns the actual
       number read. If the return value is less than count, then the
-      stream is empty or an error occured.
+      stream is empty or an error occured. Only required for readable
+      streams.
   */
-  virtual size_t read(void* buf, size_t count) = 0;
+  virtual size_t read(void* buf, size_t count) { assert(0); return 0; }
 
   /** Write a given number of bytes from the stream. Semantics is
-      similar to read(). Only valid if isWritable is true
+      similar to read(). Only valid if isWritable is true.
+
+      The returned value is the number of bytes written. However in
+      most cases, unlike for read(), a write-count less than requested
+      usually indicates an error. The implementation should throw such
+      errors as exceptions rather than expect the caller to handle
+      them.
 
       Since most implementations do NOT support writing we default to
       an assert(0) here.
@@ -57,18 +67,20 @@ class Stream
 
   /// Seek to an absolute position in this stream. Not all streams are
   /// seekable.
-  virtual void seek(size_t pos) = 0;
+  virtual void seek(size_t pos) { assert(0); }
 
   /// Get the current position in the stream. Non-seekable streams are
   /// not required to keep track of this.
-  virtual size_t tell() const = 0;
+  virtual size_t tell() const { assert(0); return 0; }
 
-  /// Return the total size of the stream. For streams where this is
-  /// not applicable, size() should return zero.
-  virtual size_t size() const = 0;
+  /// Return the total size of the stream. For streams hasSize is
+  /// false, size() should fail in some way, since it is an error to
+  /// call it in those cases.
+  virtual size_t size() const { assert(0); return 0; }
 
-  /// Returns true if the stream is empty
-  virtual bool eof() const = 0;
+  /// Returns true if the stream is empty. Required for readable
+  /// streams.
+  virtual bool eof() const { assert(0); return 0; }
 
   /// Return a pointer to the entire stream. This function (and the
   /// other getPtr() variants below) should only be implemented for

stream/tests/Makefile

@@ -1,6 +1,6 @@
-GCC=g++ -I../ -Wall
+GCC=g++ -I../ -Wall -Werror
 
-all: ogre_client_test audiere_client_test memory_server_test buffer_filter_test file_server_test slice_filter_test file_write_test
+all: ogre_client_test audiere_client_test memory_server_test buffer_filter_test file_server_test slice_filter_test file_write_test iostream_test
 
 I_OGRE=$(shell pkg-config --cflags OGRE)
 L_OGRE=$(shell pkg-config --libs OGRE)
@@ -12,6 +12,9 @@ ogre_client_test: ogre_client_test.cpp ../stream.hpp ../clients/ogre_datastream.
 audiere_client_test: audiere_client_test.cpp ../stream.hpp ../clients/audiere_file.hpp ../clients/audiere_file.cpp
 	$(GCC) $< -o $@ ../clients/audiere_file.cpp $(L_AUDIERE)
 
+iostream_test: iostream_test.cpp ../clients/io_stream.hpp
+	$(GCC) $< -o $@
+
 file_server_test: file_server_test.cpp ../stream.hpp ../servers/file_stream.hpp ../servers/std_stream.hpp
 	$(GCC) $< -o $@
 

stream/tests/iostream_test.cpp

@@ -0,0 +1,132 @@
+#include <iostream>
+#include "../clients/io_stream.hpp"
+#include "../servers/memory_stream.hpp"
+
+using namespace Mangle::Stream;
+using namespace std;
+
+void test1()
+{
+  cout << "Testing ASCII reading from memory:\n";
+  StreamPtr input(new MemoryStream("hello you world you", 19));
+  MangleIStream inp(input);
+
+  string str;
+  while(!inp.eof())
+    {
+      inp >> str;
+      cout << "Got: " << str << endl;
+    }
+}
+
+class Dummy : public Stream
+{
+  int count;
+
+public:
+
+  Dummy() : count(0)
+  {
+  }
+
+  size_t read(void *ptr, size_t num)
+  {
+    char *p = (char*)ptr;
+    char *start = p;
+    for(; (count < 2560) && (p-start < (int)num); count++)
+      {
+        *p = count / 10;
+        p++;
+      }
+    return p-start;
+  }
+
+  bool eof() const { return count == 2560; }
+};
+
+void test2()
+{
+  cout << "Testing binary reading from non-memory:\n";
+
+  StreamPtr input(new Dummy);
+  MangleIStream inp(input);
+
+  int x = 0;
+  while(!inp.eof())
+    {
+      unsigned char buf[5];
+      inp.read((char*)buf,5);
+
+      // istream doesn't set eof() until we read _beyond_ the end of
+      // the stream, so we need an extra check.
+      if(inp.gcount() == 0) break;
+
+      /*
+      for(int i=0;i<5;i++)
+        cout << (int)buf[i] << " ";
+      cout << endl;
+      */
+
+      assert(buf[4] == buf[0]);
+      assert(buf[0] == x/2);
+      x++;
+    }
+  cout << "  Done\n";
+}
+
+struct Dummy2 : Stream
+{
+  Dummy2() 
+  {
+    isWritable = true;
+    isReadable = false;
+  }
+
+  size_t write(const void *ptr, size_t num)
+  {
+    const char *p = (const char*)ptr;
+    cout << "    Got: ";
+    for(unsigned i=0;i<num;i++)
+      cout << *(p++) << " ";
+    cout << endl;
+    return num;
+  }
+};
+
+void test3()
+{
+  cout << "Writing to dummy stream:\n";
+
+  cout << "  Pure dummy test:\n";
+  StreamPtr output(new Dummy2);
+  output->write("testing", 7);
+
+  cout << "  Running through MangleOStream:\n";
+  MangleOStream out(output);
+  out << "hello";
+  out << " - are you ok?";
+  cout << "  Flushing:\n";
+  out.flush();
+
+  cout << "  Writing a hell of a lot of characters:\n";
+  for(int i=0; i<127; i++)
+    out << "xxxxxxxx"; // 127 * 8 = 1016
+  out << "fffffff"; // +7 = 1023
+  cout << "  Just one more:\n";
+  out << "y";
+  cout << "  And oooone more:\n";
+  out << "z";
+
+  cout << "  Flushing again:\n";
+  out.flush();
+  cout << "  Writing some more and exiting:\n";
+  out << "blah bleh blob";
+}
+
+int main()
+{
+  test1();
+  test2();
+  test3();
+  return 0;
+}

stream/tests/output/iostream_test.out

@@ -0,0 +1,21 @@
+Testing ASCII reading from memory:
+Got: hello
+Got: you
+Got: world
+Got: you
+Testing binary reading from non-memory:
+  Done
+Writing to dummy stream:
+  Pure dummy test:
+    Got: t e s t i n g 
+  Running through MangleOStream:
+  Flushing:
+    Got: h e l l o   -   a r e   y o u   o k ? 
+  Writing a hell of a lot of characters:
+  Just one more:
+  And oooone more:
+    Got: x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x f f f f f f f y 
+  Flushing again:
+    Got: z 
+  Writing some more and exiting:
+    Got: b l a h   b l e h   b l o b