feat: add new GGUFValueType.OBJ virtual type

The content of the OBJ type is actually a list of all key names of the object.

* GGUFWriter:
  * add `def add_kv(self, key: str, val: Any) -> None`:  This will be added based on the val type
  * add `def add_dict(self, key: str, val: dict) -> None`: add object(dict) value
* constants:
  * `GGUFValueType.get_type`: Added support for Numpy's integers and floating-point numbers, and selected the appropriate number of digits based on the size of the integer.
* gguf_reader:
  * add `ReaderField.get`: to return the value of the field
* Unit test added.

Related Issues: ggml-org#4868, ggml-org#2872

gguf-py/tests/test_constants.py

@@ -0,0 +1,32 @@
+import sys
+from pathlib import Path
+import numpy as np
+import unittest
+
+# Necessary to load the local gguf package
+sys.path.insert(0, str(Path(__file__).parent.parent))
+
+from gguf.constants import GGUFValueType
+
+class TestGGUFValueType(unittest.TestCase):
+
+    def test_get_type(self):
+        self.assertEqual(GGUFValueType.get_type("test"), GGUFValueType.STRING)
+        self.assertEqual(GGUFValueType.get_type([1, 2, 3]), GGUFValueType.ARRAY)
+        self.assertEqual(GGUFValueType.get_type(1.0), GGUFValueType.FLOAT32)
+        self.assertEqual(GGUFValueType.get_type(True), GGUFValueType.BOOL)
+        self.assertEqual(GGUFValueType.get_type(b"test"), GGUFValueType.STRING)
+        self.assertEqual(GGUFValueType.get_type(np.uint8(1)), GGUFValueType.UINT8)
+        self.assertEqual(GGUFValueType.get_type(np.uint16(1)), GGUFValueType.UINT16)
+        self.assertEqual(GGUFValueType.get_type(np.uint32(1)), GGUFValueType.UINT32)
+        self.assertEqual(GGUFValueType.get_type(np.uint64(1)), GGUFValueType.UINT64)
+        self.assertEqual(GGUFValueType.get_type(np.int8(-1)), GGUFValueType.INT8)
+        self.assertEqual(GGUFValueType.get_type(np.int16(-1)), GGUFValueType.INT16)
+        self.assertEqual(GGUFValueType.get_type(np.int32(-1)), GGUFValueType.INT32)
+        self.assertEqual(GGUFValueType.get_type(np.int64(-1)), GGUFValueType.INT64)
+        self.assertEqual(GGUFValueType.get_type(np.float32(1.0)), GGUFValueType.FLOAT32)
+        self.assertEqual(GGUFValueType.get_type(np.float64(1.0)), GGUFValueType.FLOAT64)
+        self.assertEqual(GGUFValueType.get_type({"k": 12}), GGUFValueType.OBJ)
+
+if __name__ == '__main__':
+    unittest.main()