Refactor gguf scripts to improve metadata handling

Added contents method to ReaderField class
Added endianess property to GGUFReader class

Author: CISC

gguf-py/gguf/gguf_reader.py

@@ -6,6 +6,7 @@
 
 import logging
 import os
+import sys
 from collections import OrderedDict
 from typing import Any, Literal, NamedTuple, TypeVar, Union
 
@@ -15,7 +16,6 @@
 from .quants import quant_shape_to_byte_shape
 
 if __name__ == "__main__":
-    import sys
     from pathlib import Path
 
     # Allow running file in package as a script.
@@ -28,6 +28,7 @@
     GGUF_VERSION,
     GGMLQuantizationType,
     GGUFValueType,
+    GGUFEndian,
 )
 
 logger = logging.getLogger(__name__)
@@ -53,6 +54,48 @@ class ReaderField(NamedTuple):
 
     types: list[GGUFValueType] = []
 
+    def contents(self, index_or_slice: int | slice = slice(None)) -> Any:
+        if self.types:
+            to_string = lambda x: str(x.tobytes(), encoding='utf-8')
+            main_type = self.types[0]
+
+            if main_type == GGUFValueType.ARRAY:
+                sub_type = self.types[-1]
+
+                if sub_type == GGUFValueType.STRING:
+                    indices = self.data[index_or_slice]
+
+                    if isinstance(index_or_slice, int):
+                        return to_string(self.parts[indices])
+                    else:
+                        return [to_string(self.parts[idx]) for idx in indices]
+                else:
+                    # FIXME: When/if _get_field_parts() support multi-dimensional arrays, this must do so too
+
+                    # Check if it's unsafe to perform slice optimization on data
+                    # if any(True for idx in self.data if len(self.parts[idx]) != 1):
+                    #     optim_slice = slice(None)
+                    # else:
+                    #     optim_slice = index_or_slice
+                    #     index_or_slice = slice(None)
+
+                    # if isinstance(optim_slice, int):
+                    #     return self.parts[self.data[optim_slice]].tolist()[0]
+                    # else:
+                    #     return [pv for idx in self.data[optim_slice] for pv in self.parts[idx].tolist()][index_or_slice]
+
+                    if isinstance(index_or_slice, int):
+                        return self.parts[self.data[index_or_slice]].tolist()[0]
+                    else:
+                        return [pv for idx in self.data[index_or_slice] for pv in self.parts[idx].tolist()]
+
+            if main_type == GGUFValueType.STRING:
+                return to_string(self.parts[-1])
+            else:
+                return self.parts[-1].tolist()[0]
+
+        return None
+
 
 class ReaderTensor(NamedTuple):
     name: str
@@ -105,6 +148,15 @@ def __init__(self, path: os.PathLike[str] | str, mode: Literal['r', 'r+', 'c'] =
         version = temp_version[0]
         if version not in READER_SUPPORTED_VERSIONS:
             raise ValueError(f'Sorry, file appears to be version {version} which we cannot handle')
+        if sys.byteorder == "little":
+            # Host is little endian
+            host_endian = GGUFEndian.LITTLE
+            swapped_endian = GGUFEndian.BIG
+        else:
+            # Sorry PDP or other weird systems that don't use BE or LE.
+            host_endian = GGUFEndian.BIG
+            swapped_endian = GGUFEndian.LITTLE
+        self.endianess = swapped_endian if self.byte_order == "S" else host_endian
         self.fields: OrderedDict[str, ReaderField] = OrderedDict()
         self.tensors: list[ReaderTensor] = []
         offs += self._push_field(ReaderField(offs, 'GGUF.version', [temp_version], [0], [GGUFValueType.UINT32]))
@@ -190,6 +242,7 @@ def _get_field_parts(
             offs += int(alen.nbytes)
             aparts: list[npt.NDArray[Any]] = [raw_itype, alen]
             data_idxs: list[int] = []
+            # FIXME: Handle multi-dimensional arrays properly instead of flattening
             for idx in range(alen[0]):
                 curr_size, curr_parts, curr_idxs, curr_types = self._get_field_parts(offs, raw_itype[0])
                 if idx == 0: