Improved OUTPUT_BUFFER_RW macro

Author: jim-easterbrook

CHANGELOG.txt

@@ -26,9 +26,10 @@ Changes in v0.18.0:
   4/ Add data() method to exiv2.PreviewImage, deprecate pData() method.
   5/ Deprecated many BasicIo methods (read, write, seek, etc.) that should not
      be needed in Python scripts. Please let me know if this is a problem.
-  6/ Deprecated 'buffer interface' to BasicIo, DataBuf, and PreviewImage. They
+  6/ BasicIo.read (& readOrThrow) now extract count from the buffer size.
+  7/ Deprecated 'buffer interface' to BasicIo, DataBuf, and PreviewImage. They
      all have 'data()' to get their contents.
-  7/ Invalidate data iterators if data is deleted. (Requires swig >= 4.4)
+  8/ Invalidate data iterators if data is deleted. (Requires swig >= 4.4)
 
 Changes in v0.17.3:
   1/ Binary wheels incorporate libexiv2 v0.28.5.

src/interface/shared/buffers.i

@@ -71,7 +71,8 @@ _HOLD_BUFFER(hold_funcs)
 // Macro for output writeable byte buffer
 %define OUTPUT_BUFFER_RW(buf_type, count_type)
 %typemap(doctype) buf_type "writeable :py:term:`bytes-like object`";
-%typemap(in) (buf_type) (Py_buffer _global_buff) {
+#if #count_type != ""
+%typemap(in) (buf_type, count_type) (Py_buffer _global_buff) {
     _global_buff.obj = NULL;
     if (PyObject_GetBuffer(
             $input, &_global_buff, PyBUF_CONTIG | PyBUF_WRITABLE) < 0) {
@@ -80,18 +81,35 @@ _HOLD_BUFFER(hold_funcs)
                        $symname, $argnum);
     }
     $1 = ($1_ltype) _global_buff.buf;
+    $2 = ($2_ltype) _global_buff.len;
 }
-%typemap(check) (buf_type, count_type) {
-    if ($2 > ($2_ltype) _global_buff.len) {
+%typemap(freearg) (buf_type, count_type) %{
+    if (_global_buff.obj) {
+        PyBuffer_Release(&_global_buff);
+    }
+%}
+#else
+%typemap(in) (buf_type) (Py_buffer _global_buff) {
+    _global_buff.obj = NULL;
+    if (PyObject_GetBuffer(
+            $input, &_global_buff, PyBUF_CONTIG | PyBUF_WRITABLE) < 0) {
+        PyErr_Clear();
+        %argument_fail(SWIG_TypeError, "writable bytes-like object",
+                       $symname, $argnum);
+    }
+    // check buffer is large enough, assumes arg1 points to self
+    if ((Py_ssize_t) arg1->size() > _global_buff.len) {
         %argument_fail(SWIG_ValueError, "buffer too small",
                        $symname, $argnum);
     }
+    $1 = ($1_ltype) _global_buff.buf;
 }
 %typemap(freearg) (buf_type) %{
     if (_global_buff.obj) {
         PyBuffer_Release(&_global_buff);
     }
 %}
+#endif
 %typemap(typecheck, precedence=SWIG_TYPECHECK_CHAR_PTR) buf_type %{
     $1 = PyObject_CheckBuffer($input) ? 1 : 0;
 %}

src/interface/value.i

@@ -94,15 +94,8 @@ INPUT_BUFFER_RO(const Exiv2::byte* buf, long len)
 INPUT_BUFFER_RO(const Exiv2::byte* buf, size_t len)
 #endif
 // Value::copy can write to a Python buffer
-OUTPUT_BUFFER_RW(Exiv2::byte* buf, Exiv2::ByteOrder byteOrder)
-// redefine check typemap
-%typemap(check) (Exiv2::byte* buf, Exiv2::ByteOrder byteOrder) {
-    // check buffer is large enough, assumes arg1 points to self
-    if ((Py_ssize_t) arg1->size() > _global_buff.len) {
-        %argument_fail(SWIG_ValueError, "buffer too small",
-                       $symname, $argnum);
-    }
-}
+OUTPUT_BUFFER_RW(Exiv2::byte* buf,)
+
 // Downcast base class pointers to derived class
 // Convert exiv2 type id to the appropriate value class type info
 %fragment("get_type_object", "header") {

src/swig-0_27_7/basicio_wrap.cxx

@@ -5276,13 +5276,10 @@ SWIGINTERN PyObject *_wrap_BasicIo_read__SWIG_1(PyObject *self, PyObject *args)
   void *argp1 = 0 ;
   int res1 = 0 ;
   Py_buffer _global_buff ;
-  long val3 ;
-  int ecode3 = 0 ;
   PyObject * obj1 = 0 ;
-  PyObject * obj2 = 0 ;
   long result;
 
-  if (!PyArg_UnpackTuple(args, "BasicIo_read", 2, 2, &obj1, &obj2)) SWIG_fail;
+  if (!PyArg_UnpackTuple(args, "BasicIo_read", 1, 1, &obj1)) SWIG_fail;
   res1 = SWIG_ConvertPtr(self, &argp1,SWIGTYPE_p_Exiv2__BasicIo, 0 |  0 );
   if (!SWIG_IsOK(res1)) {
     SWIG_exception_fail(SWIG_ArgError(res1), "in method '" "BasicIo_read" "', argument " "1"" of type '" "Exiv2::BasicIo *""'"); 
@@ -5297,23 +5294,13 @@ SWIGINTERN PyObject *_wrap_BasicIo_read__SWIG_1(PyObject *self, PyObject *args)
       ;
     }
     arg2 = (Exiv2::byte *) _global_buff.buf;
+    arg3 = (long) _global_buff.len;
   }
-  ecode3 = SWIG_AsVal_long(obj2, &val3);
-  if (!SWIG_IsOK(ecode3)) {
-    SWIG_exception_fail(SWIG_ArgError(ecode3), "in method '" "BasicIo_read" "', argument " "3"" of type '" "long""'");
-  } 
-  arg3 = static_cast< long >(val3);
   {
 #ifndef NO_RELEASE_BasicIo_read
     release_views(self);
 #endif
   }
-  {
-    if (arg3 > (long) _global_buff.len) {
-      SWIG_exception_fail(SWIG_ArgError(SWIG_ValueError), "in method '" "BasicIo_read" "', argument " "2"" of type '" "buffer too small""'")
-      ;
-    }
-  }
   {
     PyErr_WarnEx(PyExc_DeprecationWarning,
       "Python scripts should not need to call ""Exiv2::BasicIo::read", 1);
@@ -5349,7 +5336,7 @@ SWIGINTERN PyObject *_wrap_BasicIo_read__SWIG_1(PyObject *self, PyObject *args)
 
 SWIGINTERN PyObject *_wrap_BasicIo_read(PyObject *self, PyObject *args) {
   Py_ssize_t argc;
-  PyObject *argv[4] = {
+  PyObject *argv[3] = {
     0
   };
   Py_ssize_t ii;
@@ -5358,16 +5345,24 @@ SWIGINTERN PyObject *_wrap_BasicIo_read(PyObject *self, PyObject *args) {
   if (!PyTuple_Check(args)) SWIG_fail;
   argc = PyObject_Length(args);
   argv[0] = self;
-  for (ii = 0; (ii < 2) && (ii < argc); ii++) {
+  for (ii = 0; (ii < 1) && (ii < argc); ii++) {
     argv[ii + 1] = PyTuple_GET_ITEM(args,ii);
   }
   argc++;
   if (argc == 2) {
-    PyObject *retobj = _wrap_BasicIo_read__SWIG_0(self, args);
-    if (!SWIG_Python_TypeErrorOccurred(retobj)) return retobj;
-    SWIG_fail;
+    int _v = 0;
+    {
+      {
+        int res = SWIG_AsVal_long(argv[1], NULL);
+        _v = SWIG_CheckState(res);
+      }
+    }
+    if (!_v) goto check_1;
+    return _wrap_BasicIo_read__SWIG_0(self, args);
   }
-  if (argc == 3) {
+check_1:
+  
+  if (argc == 2) {
     PyObject *retobj = _wrap_BasicIo_read__SWIG_1(self, args);
     if (!SWIG_Python_TypeErrorOccurred(retobj)) return retobj;
     SWIG_fail;

src/swig-0_27_7/exif_wrap.cxx

@@ -6361,6 +6361,11 @@ SWIGINTERN PyObject *_wrap_ExifData_iterator_copy(PyObject *self, PyObject *args
       SWIG_exception_fail(SWIG_ArgError(SWIG_TypeError), "in method '" "ExifData_iterator_copy" "', argument " "2"" of type '" "writable bytes-like object""'")
       ;
     }
+    // check buffer is large enough, assumes arg1 points to self
+    if ((Py_ssize_t) arg1->size() > _global_buff.len) {
+      SWIG_exception_fail(SWIG_ArgError(SWIG_ValueError), "in method '" "ExifData_iterator_copy" "', argument " "2"" of type '" "buffer too small""'")
+      ;
+    }
     arg2 = (Exiv2::byte *) _global_buff.buf;
   }
   {
@@ -6376,13 +6381,6 @@ SWIGINTERN PyObject *_wrap_ExifData_iterator_copy(PyObject *self, PyObject *args
     }
     arg3 = static_cast< Exiv2::ByteOrder >(PyLong_AsLong(obj2));
   }
-  {
-    // check buffer is large enough, assumes arg1 points to self
-    if ((Py_ssize_t) arg1->size() > _global_buff.len) {
-      SWIG_exception_fail(SWIG_ArgError(SWIG_ValueError), "in method '" "ExifData_iterator_copy" "', argument " "2"" of type '" "buffer too small""'")
-      ;
-    }
-  }
   {
     try {
       result = (long)(*arg1)->copy(arg2,arg3);
@@ -7832,6 +7830,11 @@ SWIGINTERN PyObject *_wrap_Exifdatum_copy(PyObject *self, PyObject *args) {
       SWIG_exception_fail(SWIG_ArgError(SWIG_TypeError), "in method '" "Exifdatum_copy" "', argument " "2"" of type '" "writable bytes-like object""'")
       ;
     }
+    // check buffer is large enough, assumes arg1 points to self
+    if ((Py_ssize_t) arg1->size() > _global_buff.len) {
+      SWIG_exception_fail(SWIG_ArgError(SWIG_ValueError), "in method '" "Exifdatum_copy" "', argument " "2"" of type '" "buffer too small""'")
+      ;
+    }
     arg2 = (Exiv2::byte *) _global_buff.buf;
   }
   {
@@ -7847,13 +7850,6 @@ SWIGINTERN PyObject *_wrap_Exifdatum_copy(PyObject *self, PyObject *args) {
     }
     arg3 = static_cast< Exiv2::ByteOrder >(PyLong_AsLong(obj2));
   }
-  {
-    // check buffer is large enough, assumes arg1 points to self
-    if ((Py_ssize_t) arg1->size() > _global_buff.len) {
-      SWIG_exception_fail(SWIG_ArgError(SWIG_ValueError), "in method '" "Exifdatum_copy" "', argument " "2"" of type '" "buffer too small""'")
-      ;
-    }
-  }
   {
     try {
       result = (long)((Exiv2::Exifdatum const *)arg1)->copy(arg2,arg3);

src/swig-0_27_7/iptc_wrap.cxx

@@ -6015,6 +6015,11 @@ SWIGINTERN PyObject *_wrap_IptcData_iterator_copy(PyObject *self, PyObject *args
       SWIG_exception_fail(SWIG_ArgError(SWIG_TypeError), "in method '" "IptcData_iterator_copy" "', argument " "2"" of type '" "writable bytes-like object""'")
       ;
     }
+    // check buffer is large enough, assumes arg1 points to self
+    if ((Py_ssize_t) arg1->size() > _global_buff.len) {
+      SWIG_exception_fail(SWIG_ArgError(SWIG_ValueError), "in method '" "IptcData_iterator_copy" "', argument " "2"" of type '" "buffer too small""'")
+      ;
+    }
     arg2 = (Exiv2::byte *) _global_buff.buf;
   }
   {
@@ -6030,13 +6035,6 @@ SWIGINTERN PyObject *_wrap_IptcData_iterator_copy(PyObject *self, PyObject *args
     }
     arg3 = static_cast< Exiv2::ByteOrder >(PyLong_AsLong(obj2));
   }
-  {
-    // check buffer is large enough, assumes arg1 points to self
-    if ((Py_ssize_t) arg1->size() > _global_buff.len) {
-      SWIG_exception_fail(SWIG_ArgError(SWIG_ValueError), "in method '" "IptcData_iterator_copy" "', argument " "2"" of type '" "buffer too small""'")
-      ;
-    }
-  }
   {
     try {
       result = (long)(*arg1)->copy(arg2,arg3);
@@ -7371,6 +7369,11 @@ SWIGINTERN PyObject *_wrap_Iptcdatum_copy(PyObject *self, PyObject *args) {
       SWIG_exception_fail(SWIG_ArgError(SWIG_TypeError), "in method '" "Iptcdatum_copy" "', argument " "2"" of type '" "writable bytes-like object""'")
       ;
     }
+    // check buffer is large enough, assumes arg1 points to self
+    if ((Py_ssize_t) arg1->size() > _global_buff.len) {
+      SWIG_exception_fail(SWIG_ArgError(SWIG_ValueError), "in method '" "Iptcdatum_copy" "', argument " "2"" of type '" "buffer too small""'")
+      ;
+    }
     arg2 = (Exiv2::byte *) _global_buff.buf;
   }
   {
@@ -7386,13 +7389,6 @@ SWIGINTERN PyObject *_wrap_Iptcdatum_copy(PyObject *self, PyObject *args) {
     }
     arg3 = static_cast< Exiv2::ByteOrder >(PyLong_AsLong(obj2));
   }
-  {
-    // check buffer is large enough, assumes arg1 points to self
-    if ((Py_ssize_t) arg1->size() > _global_buff.len) {
-      SWIG_exception_fail(SWIG_ArgError(SWIG_ValueError), "in method '" "Iptcdatum_copy" "', argument " "2"" of type '" "buffer too small""'")
-      ;
-    }
-  }
   {
     try {
       result = (long)((Exiv2::Iptcdatum const *)arg1)->copy(arg2,arg3);

src/swig-0_27_7/metadatum_wrap.cxx

@@ -5678,6 +5678,11 @@ SWIGINTERN PyObject *_wrap_Metadatum_copy(PyObject *self, PyObject *args) {
       SWIG_exception_fail(SWIG_ArgError(SWIG_TypeError), "in method '" "Metadatum_copy" "', argument " "2"" of type '" "writable bytes-like object""'")
       ;
     }
+    // check buffer is large enough, assumes arg1 points to self
+    if ((Py_ssize_t) arg1->size() > _global_buff.len) {
+      SWIG_exception_fail(SWIG_ArgError(SWIG_ValueError), "in method '" "Metadatum_copy" "', argument " "2"" of type '" "buffer too small""'")
+      ;
+    }
     arg2 = (Exiv2::byte *) _global_buff.buf;
   }
   {
@@ -5693,13 +5698,6 @@ SWIGINTERN PyObject *_wrap_Metadatum_copy(PyObject *self, PyObject *args) {
     }
     arg3 = static_cast< Exiv2::ByteOrder >(PyLong_AsLong(obj2));
   }
-  {
-    // check buffer is large enough, assumes arg1 points to self
-    if ((Py_ssize_t) arg1->size() > _global_buff.len) {
-      SWIG_exception_fail(SWIG_ArgError(SWIG_ValueError), "in method '" "Metadatum_copy" "', argument " "2"" of type '" "buffer too small""'")
-      ;
-    }
-  }
   {
     try {
       result = (long)((Exiv2::Metadatum const *)arg1)->copy(arg2,arg3);