Support writing output to memory with SFOutputStream.

Signed-off-by: Stefan Westerfeld <stefan@space.twc.de>

src/sfinputstream.cc

@@ -169,7 +169,7 @@ SFInputStream::close()
 static sf_count_t
 virtual_get_len (void *data)
 {
-  SFInputStream::VirtualData *vdata = static_cast<SFInputStream::VirtualData *> (data);
+  SFVirtualData *vdata = static_cast<SFVirtualData *> (data);
 
   return vdata->mem->size();
 }
@@ -177,7 +177,7 @@ virtual_get_len (void *data)
 static sf_count_t
 virtual_seek (sf_count_t offset, int whence, void *data)
 {
-  SFInputStream::VirtualData *vdata = static_cast<SFInputStream::VirtualData *> (data);
+  SFVirtualData *vdata = static_cast<SFVirtualData *> (data);
 
   if (whence == SEEK_CUR)
     {
@@ -200,7 +200,7 @@ virtual_seek (sf_count_t offset, int whence, void *data)
 static sf_count_t
 virtual_read (void *ptr, sf_count_t count, void *data)
 {
-  SFInputStream::VirtualData *vdata = static_cast<SFInputStream::VirtualData *> (data);
+  SFVirtualData *vdata = static_cast<SFVirtualData *> (data);
 
   int rcount = 0;
   if (size_t (vdata->offset + count) <= vdata->mem->size())
@@ -229,7 +229,7 @@ virtual_read (void *ptr, sf_count_t count, void *data)
 static sf_count_t
 virtual_write (const void *ptr, sf_count_t count, void *data)
 {
-  SFInputStream::VirtualData *vdata = static_cast<SFInputStream::VirtualData *> (data);
+  SFVirtualData *vdata = static_cast<SFVirtualData *> (data);
 
   const unsigned char *uptr = static_cast<const unsigned char *> (ptr);
   for (sf_count_t i = 0; i < count; i++)
@@ -248,22 +248,26 @@ virtual_write (const void *ptr, sf_count_t count, void *data)
 static sf_count_t
 virtual_tell (void *data)
 {
-  SFInputStream::VirtualData *vdata = static_cast<SFInputStream::VirtualData *> (data);
+  SFVirtualData *vdata = static_cast<SFVirtualData *> (data);
   return vdata->offset;
 }
 
-Error
-SFInputStream::open (const vector<unsigned char> *data)
-{
-  virtual_data.mem = const_cast<vector<unsigned char> *> (data);
-  SF_VIRTUAL_IO sf_virtual_io = {
+SFVirtualData::SFVirtualData() :
+  io {
     virtual_get_len,
     virtual_seek,
     virtual_read,
     virtual_write,
     virtual_tell
-  };
+  }
+{
+}
+
+Error
+SFInputStream::open (const vector<unsigned char> *data)
+{
+  m_virtual_data.mem = const_cast<vector<unsigned char> *> (data);
   return open ([&] (SF_INFO *sfinfo) {
-    return sf_open_virtual (&sf_virtual_io, SFM_READ, sfinfo, &virtual_data);
+    return sf_open_virtual (&m_virtual_data.io, SFM_READ, sfinfo, &m_virtual_data);
   });
 }

src/sfinputstream.hh

@@ -25,18 +25,21 @@
 
 #include "audiostream.hh"
 
-class SFInputStream : public AudioInputStream
+/* to support virtual io read/write from/to memory */
+struct SFVirtualData
 {
-public:
-  /* to support read from memory */
-  struct VirtualData
-  {
-    std::vector<unsigned char> *mem    = nullptr;
-    sf_count_t                  offset = 0;
-  };
+  SFVirtualData();
 
+  std::vector<unsigned char> *mem    = nullptr;
+  sf_count_t                  offset = 0;
+  SF_VIRTUAL_IO               io;
+};
+
+class SFInputStream : public AudioInputStream
+{
 private:
-  VirtualData virtual_data;
+  SFVirtualData m_virtual_data;
+
   SNDFILE    *m_sndfile = nullptr;
   int         m_n_channels = 0;
   int         m_n_values = 0;

src/sfoutputstream.cc

@@ -31,6 +31,14 @@ SFOutputStream::~SFOutputStream()
 
 Error
 SFOutputStream::open (const string& filename, int n_channels, int sample_rate, int bit_depth, size_t n_frames)
+{
+  return open ([&] (SF_INFO *sfinfo) {
+    return sf_open (filename.c_str(), SFM_WRITE, sfinfo);
+  }, n_channels, sample_rate, bit_depth, n_frames);
+}
+
+Error
+SFOutputStream::open (std::function<SNDFILE* (SF_INFO *)> open_func, int n_channels, int sample_rate, int bit_depth, size_t n_frames)
 {
   assert (m_state == State::NEW);
 
@@ -52,7 +60,7 @@ SFOutputStream::open (const string& filename, int n_channels, int sample_rate, i
       m_bit_depth   = 16;
     }
 
-  m_sndfile = sf_open (filename.c_str(), SFM_WRITE, &sfinfo);
+  m_sndfile = open_func (&sfinfo);
   int error = sf_error (m_sndfile);
   if (error)
     {
@@ -122,3 +130,13 @@ SFOutputStream::n_channels() const
 {
   return m_n_channels;
 }
+
+Error
+SFOutputStream::open (vector<unsigned char> *data, int n_channels, int sample_rate, int bit_depth, size_t n_frames)
+{
+  m_virtual_data.mem = data;
+
+  return open ([&] (SF_INFO *sfinfo) {
+    return sf_open_virtual (&m_virtual_data.io, SFM_WRITE, sfinfo, &m_virtual_data);
+  }, n_channels, sample_rate, bit_depth, n_frames);
+}

src/sfoutputstream.hh

@@ -23,9 +23,12 @@
 #include <sndfile.h>
 
 #include "audiostream.hh"
+#include "sfinputstream.hh"
 
 class SFOutputStream : public AudioOutputStream
 {
+  SFVirtualData m_virtual_data;
+
   SNDFILE    *m_sndfile = nullptr;
   int         m_bit_depth = 0;
   int         m_sample_rate = 0;
@@ -38,10 +41,12 @@ class SFOutputStream : public AudioOutputStream
   };
   State       m_state = State::NEW;
 
+  Error open (std::function<SNDFILE* (SF_INFO *)> open_func, int n_channels, int sample_rate, int bit_depth, size_t n_frames);
 public:
   ~SFOutputStream();
 
   Error  open (const std::string& filename, int n_channels, int sample_rate, int bit_depth, size_t n_frames);
+  Error  open (std::vector<unsigned char> *data, int n_channels, int sample_rate, int bit_depth, size_t n_frames);
   Error  write_frames (const std::vector<float>& frames) override;
   Error  close() override;
   int    bit_depth() const override;