Add Java nivision wrappers.

Only very basic testing performed to date.

The wrappers are still a bit incomplete (some structures and functions),
but are much more complete than the old ones.

Fixes artf3796.

Changes from initial changeset:
- Use // for comments.
- Add auto-generate notices to the beginning of each generated file.
- Include error number with error text in exception.
- Add free() function to structures.
- Fix out-of-order / non-array enums.
- Avoid duplicate calls to DisposedStruct.write() as .getAddress() does it.
- Refactor OpaqueStruct.
- Default to no null allowed except when overridden.
- Implement unowned return values.
- Add gen_struct_sizer script.

Change-Id: Ie0d102c45817ea8812d98fe4938d1a2255c61664

wpilibj/wpilibJavaJNI/nivision/gen_struct_sizer.py

@@ -0,0 +1,113 @@
+from __future__ import print_function
+import sys
+import os
+import re
+try:
+    import configparser
+except ImportError:
+    import ConfigParser as configparser
+
+from nivision_parse import *
+
+class StructSizerEmitter:
+    def __init__(self, out, config):
+        self.out = out
+        self.config = config
+        print("""#include <stdio.h>
+#include <nivision.h>
+
+int main()
+{
+    printf("[_platform_]\\npointer=%d\\n", (int)sizeof(void*));
+""", file=self.out)
+
+    def finish(self):
+        print("}", file=self.out)
+
+    def config_get(self, section, option, fallback):
+        try:
+            return self.config.get(section, option)
+        except (ValueError, configparser.NoSectionError, configparser.NoOptionError):
+            return fallback
+
+    def config_getboolean(self, section, option, fallback):
+        try:
+            return self.config.getboolean(section, option)
+        except (ValueError, configparser.NoSectionError, configparser.NoOptionError):
+            return fallback
+
+    def block_comment(self, comment):
+        pass
+
+    def opaque_struct(self, name):
+        pass
+
+    def define(self, name, value, comment):
+        pass
+
+    def text(self, text):
+        print(text, file=self.out)
+
+    def static_const(self, name, ctype, value):
+        pass
+
+    def enum(self, name, values):
+        pass
+
+    def typedef(self, name, typedef, arr):
+        pass
+
+    def typedef_function(self, name, restype, params):
+        pass
+
+    def function(self, name, restype, params):
+        pass
+
+    def structunion(self, ctype, name, fields):
+        if name in opaque_structs:
+            return
+
+        print('printf("[{name}]\\n_SIZE_=%d\\n", (int)sizeof({name}));'.format(name=name), file=self.out)
+
+        for fname, ftype, arr, comment in fields:
+            if ':' in fname:
+                continue # can't handle bitfields
+            print('printf("{field}=%d\\n", (int)offsetof({name}, {field}));'.format(name=name, field=fname), file=self.out)
+
+    def struct(self, name, fields):
+        self.structunion("Structure", name, fields)
+
+    def union(self, name, fields):
+        self.structunion("Union", name, fields)
+
+def generate(srcdir, configpath=None, nivisionhpath=None):
+    # read config file
+    config = configparser.ConfigParser()
+    config.read(configpath)
+    block_comment_exclude = set(x.strip() for x in
+            config.get("Block Comment", "exclude").splitlines())
+
+    # open input file
+    inf = open(nivisionhpath)
+
+    # prescan for undefined structures
+    prescan_file(inf)
+    inf.seek(0)
+
+    # generate
+    with open("struct_sizer.c", "wt") as out:
+        emit = StructSizerEmitter(out, config)
+        parse_file(emit, inf, block_comment_exclude)
+        emit.finish()
+
+if __name__ == "__main__":
+    if len(sys.argv) < 2:
+        print("Usage: gen_struct_sizer.py <nivision.h> [config.ini]")
+        exit(0)
+
+    fname = sys.argv[1]
+    configname = "nivision_2011.ini"
+    if len(sys.argv) >= 3:
+        configname = sys.argv[2]
+
+    generate("", configname, fname)