Fix compiler warnings from Visual Studio.

Author: behackett

bson/_cbsonmodule.c

@@ -129,7 +129,7 @@ static PyObject* _error(char* name) {
 /* Safely downcast from Py_ssize_t to int, setting an
  * exception and returning -1 on error. */
 static int
-_downcast_and_check(Py_ssize_t size, unsigned extra) {
+_downcast_and_check(Py_ssize_t size, int extra) {
  if (size > BSON_MAX_SIZE || ((BSON_MAX_SIZE - extra) < size)) {
  PyObject* InvalidStringData = _error("InvalidStringData");
  if (InvalidStringData) {
@@ -1382,9 +1382,9 @@ static PyObject* get_value(PyObject* self, const char* buffer, int* position,
  case 3:
  {
  PyObject* collection;
- unsigned size;
+ int size;
  memcpy(&size, buffer + *position, 4);
- if (max < size) {
+ if (size < 0 || max < size) {
  goto invalid;
  }
  value = elements_to_dict(self, buffer + *position + 4,
@@ -1667,7 +1667,7 @@ static PyObject* get_value(PyObject* self, const char* buffer, int* position,
  int flags;
  size_t flags_length, i;
  size_t pattern_length = strlen(buffer + *position);
- if (max < pattern_length || pattern_length > BSON_MAX_SIZE) {
+ if (pattern_length > BSON_MAX_SIZE || max < (int)pattern_length) {
  goto invalid;
  }
  pattern = PyUnicode_DecodeUTF8(buffer + *position, pattern_length, "strict");
@@ -1679,7 +1679,7 @@ static PyObject* get_value(PyObject* self, const char* buffer, int* position,
  Py_DECREF(pattern);
  goto invalid;
  }
- if (max < pattern_length + flags_length) {
+ if (max < (int)(pattern_length + flags_length)) {
  Py_DECREF(pattern);
  goto invalid;
  }
@@ -1706,24 +1706,22 @@ static PyObject* get_value(PyObject* self, const char* buffer, int* position,
  }
  case 12:
  {
- size_t collection_length;
+ size_t coll_length;
  PyObject* collection;
  PyObject* id;
 
  *position += 4;
- collection_length = strlen(buffer + *position);
- if (max < collection_length || collection_length > BSON_MAX_SIZE) {
+ coll_length = strlen(buffer + *position);
+ if (coll_length > BSON_MAX_SIZE || max < (int)coll_length + 12) {
  goto invalid;
  }
- collection = PyUnicode_DecodeUTF8(buffer + *position, collection_length, "strict");
+ collection = PyUnicode_DecodeUTF8(buffer + *position,
+ coll_length, "strict");
  if (!collection) {
  return NULL;
  }
- *position += (int)collection_length + 1;
- if (max < collection_length + 12) {
- Py_DECREF(collection);
- goto invalid;
- }
+ *position += (int)coll_length + 1;
+
  id = PyObject_CallFunction(state->ObjectId, "s#", buffer + *position, 12);
  if (!id) {
  Py_DECREF(collection);
@@ -1761,7 +1759,7 @@ static PyObject* get_value(PyObject* self, const char* buffer, int* position,
 
  *position += 8;
  code_length = strlen(buffer + *position);
- if (max < 8 + code_length || code_length > BSON_MAX_SIZE) {
+ if (code_length > BSON_MAX_SIZE || max < 8 + (int)code_length) {
  goto invalid;
  }
  code = PyUnicode_DecodeUTF8(buffer + *position, code_length, "strict");
@@ -1877,7 +1875,7 @@ static PyObject* elements_to_dict(PyObject* self, const char* string, int max,
  PyObject* value;
  int type = (int)string[position++];
  size_t name_length = strlen(string + position);
- if (name_length > BSON_MAX_SIZE || position + name_length >= max) {
+ if (name_length > BSON_MAX_SIZE || position + (int)name_length >= max) {
  PyObject* InvalidBSON = _error("InvalidBSON");
  if (InvalidBSON) {
  PyErr_SetNone(InvalidBSON);
@@ -1908,7 +1906,7 @@ static PyObject* elements_to_dict(PyObject* self, const char* string, int max,
 }
 
 static PyObject* _cbson_bson_to_dict(PyObject* self, PyObject* args) {
- unsigned int size;
+ int size;
  Py_ssize_t total_size;
  const char* string;
  PyObject* bson;
@@ -1955,7 +1953,16 @@ static PyObject* _cbson_bson_to_dict(PyObject* self, PyObject* args) {
  if (!string) {
  return NULL;
  }
+
  memcpy(&size, string, 4);
+ if (size < 0) {
+ PyObject* InvalidBSON = _error("InvalidBSON");
+ if (InvalidBSON) {
+ PyErr_SetString(InvalidBSON, "invalid message size");
+ Py_DECREF(InvalidBSON);
+ }
+ return NULL;
+ }
 
  if (total_size < size) {
  PyObject* InvalidBSON = _error("InvalidBSON");
@@ -1995,7 +2002,7 @@ static PyObject* _cbson_bson_to_dict(PyObject* self, PyObject* args) {
 }
 
 static PyObject* _cbson_decode_all(PyObject* self, PyObject* args) {
- unsigned int size;
+ int size;
  Py_ssize_t total_size;
  const char* string;
  PyObject* bson;
@@ -2045,6 +2052,15 @@ static PyObject* _cbson_decode_all(PyObject* self, PyObject* args) {
  }
 
  memcpy(&size, string, 4);
+ if (size < 0) {
+ PyObject* InvalidBSON = _error("InvalidBSON");
+ if (InvalidBSON) {
+ PyErr_SetString(InvalidBSON, "invalid message size");
+ Py_DECREF(InvalidBSON);
+ }
+ Py_DECREF(result);
+ return NULL;
+ }
 
  if (total_size < size) {
  PyObject* InvalidBSON = _error("InvalidBSON");