[Python-checkins] r57228 - python/branches/alex-py3k/Modules/_bytesiomodule.c python/branches/alex-py3k/Modules/_stringiomodule.c

[alexandre.vassalotti]

Author: alexandre.vassalotti
Date: Tue Aug 21 02:16:46 2007
New Revision: 57228

Modified:
   python/branches/alex-py3k/Modules/_bytesiomodule.c
   python/branches/alex-py3k/Modules/_stringiomodule.c
Log:
Improve error messages in seek() and truncate().
Raise ValueError, instead of IOError, on invalid whence 
value in seek().
Do not call write_str() if write() argument is an empty string.
Remove relative seek support in StringIO.
Clean up the docstring of seek().


Modified: python/branches/alex-py3k/Modules/_bytesiomodule.c
==============================================================================
--- python/branches/alex-py3k/Modules/_bytesiomodule.c	(original)
+++ python/branches/alex-py3k/Modules/_bytesiomodule.c	Tue Aug 21 02:16:46 2007
@@ -320,8 +320,8 @@
     }
 
     if (size < 0) {
-        /* XXX: Give a better error message. */
-        PyErr_SetString(PyExc_ValueError, "invalid position value");
+        PyErr_Format(PyExc_ValueError,
+                     "Negative size value %zd", size);
         return NULL;
     }
 
@@ -358,6 +358,12 @@
     if (!PyArg_ParseTuple(args, "n|i:seek", &newpos, &mode))
         return NULL;
 
+    if (newpos < 0 && mode == 0) {
+        PyErr_Format(PyExc_ValueError,
+                     "Negative seek value %zd", newpos);
+        return NULL;
+    }
+
     /* mode 0: offset relative to beginning of the string.
        mode 1: offset relative to current position.
        mode 2: offset relative the end of the string. */
@@ -368,7 +374,8 @@
         newpos += self->string_size;
     }
     else if (mode != 0) {
-        PyErr_SetString(PyExc_IOError, "invalid whence value");
+        PyErr_Format(PyExc_ValueError,
+                     "Invalid whence (%i, should be 0, 1 or 2)", mode);
         return NULL;
     }
 
@@ -397,7 +404,7 @@
 bytesio_write(BytesIOObject *self, PyObject *obj)
 {
     const char *bytes;
-    Py_ssize_t size, len;
+    Py_ssize_t size, n = 0;
 
     if (PyUnicode_Check(obj)) {
         bytes = PyUnicode_AsString(obj);
@@ -408,11 +415,13 @@
             return NULL;
     }
 
-    len = write_bytes(self, bytes, size);
-    if (len == -1)
+    if (size != 0)
+        n = write_bytes(self, bytes, size);
+
+    if (n == -1)
         return NULL;
 
-    return PyInt_FromSsize_t(len);
+    return PyInt_FromSsize_t(n);
 }
 
 static PyObject *
@@ -564,8 +573,8 @@
 "\n"
 "Seek to byte offset pos relative to position indicated by whence:\n"
 "     0  Start of stream (the default).  pos should be >= 0;\n"
-"     1  Current position - whence may be negative;\n"
-"     2  End of stream - whence usually negative.\n"
+"     1  Current position - pos may be negative;\n"
+"     2  End of stream - pos usually negative.\n"
 "Returns the new absolute position.");
 
 PyDoc_STRVAR(BytesIO_write_doc,

Modified: python/branches/alex-py3k/Modules/_stringiomodule.c
==============================================================================
--- python/branches/alex-py3k/Modules/_stringiomodule.c	(original)
+++ python/branches/alex-py3k/Modules/_stringiomodule.c	Tue Aug 21 02:16:46 2007
@@ -285,8 +285,8 @@
     }
 
     if (size < 0) {
-        /* XXX: Give a better error message. */
-        PyErr_SetString(PyExc_ValueError, "invalid position value");
+        PyErr_Format(PyExc_ValueError,
+                     "Negative size value %zd", size);
         return NULL;
     }
 
@@ -323,24 +323,32 @@
     if (!PyArg_ParseTuple(args, "n|i:seek", &newpos, &mode))
         return NULL;
 
+    if (newpos < 0 && mode == 0) {
+        PyErr_Format(PyExc_ValueError,
+                     "Negative seek position %zd", newpos);
+        return NULL;
+    }
+    if (newpos != 0 && mode != 0) {
+        PyErr_SetString(PyExc_IOError, 
+                        "Can't do nonzero cur-relative seeks");
+    }
+
     /* mode 0: offset relative to beginning of the string.
-       mode 1: offset relative to current position.
-       mode 2: offset relative the end of the string. */
+       mode 1: no change to current position.
+       mode 2: change position to end of file. */
     if (mode == 1) {
-        newpos += self->pos;
+        newpos = self->pos;
     }
     else if (mode == 2) {
-        newpos += self->string_size;
+        newpos = self->string_size;
     }
     else if (mode != 0) {
-        PyErr_SetString(PyExc_IOError, "invalid whence value");
+        PyErr_Format(PyExc_ValueError,
+                     "Invalid whence (%i, should be 0, 1 or 2)", mode);
         return NULL;
     }
 
-    if (newpos < 0)
-        newpos = 0;
-
-    if (newpos >= self->string_size) {
+    if (newpos > self->string_size) {
         if (resize_buffer(self, newpos + 1) < 0)
             return NULL;  /* out of memory */
     }
@@ -362,7 +370,7 @@
 stringio_write(StringIOObject *self, PyObject *obj)
 {
     const Py_UNICODE *str;
-    Py_ssize_t size, n;
+    Py_ssize_t size, n = 0;
     PyObject *ustr = NULL;
 
     if (PyUnicode_Check(obj)) {
@@ -383,7 +391,9 @@
         return NULL;
     }
 
-    n = write_str(self, str, size);
+    if (size != 0)
+        n = write_str(self, str, size);
+
     Py_XDECREF(ustr);
     if (n == -1)
         return NULL;
@@ -528,8 +538,8 @@
 "\n"
 "Seek to byte offset pos relative to position indicated by whence:\n"
 "     0  Start of stream (the default).  pos should be >= 0;\n"
-"     1  Current position - whence may be negative;\n"
-"     2  End of stream - whence usually negative.\n"
+"     1  Current position - pos must be 0;\n"
+"     2  End of stream - pos must be 0.\n"
 "Returns the new absolute position.");
 
 PyDoc_STRVAR(StringIO_write_doc,