1 files changed, 37 insertions, 0 deletions
diff --git a/text_recognizer/data/emnist_mapping.py b/text_recognizer/data/emnist_mapping.py
new file mode 100644
index 0000000..6c4c43b
--- /dev/null
+++ b/text_recognizer/data/emnist_mapping.py
@@ -0,0 +1,37 @@
+"""Emnist mapping."""
+from typing import List, Optional, Union, Set
+
+from torch import Tensor
+
+from text_recognizer.data.base_mapping import AbstractMapping
+from text_recognizer.data.emnist import emnist_mapping
+
+
+class EmnistMapping(AbstractMapping):
+    def __init__(self, extra_symbols: Optional[Set[str]] = None) -> None:
+        self.extra_symbols = set(extra_symbols) if extra_symbols is not None else None
+        self.mapping, self.inverse_mapping, self.input_size = emnist_mapping(
+            self.extra_symbols
+        )
+        super().__init__(self.input_size, self.mapping, self.inverse_mapping)
+
+    def __attrs_post_init__(self) -> None:
+        """Post init configuration."""
+
+    def get_token(self, index: Union[int, Tensor]) -> str:
+        if (index := int(index)) in self.mapping:
+            return self.mapping[index]
+        raise KeyError(f"Index ({index}) not in mapping.")
+
+    def get_index(self, token: str) -> Tensor:
+        if token in self.inverse_mapping:
+            return Tensor(self.inverse_mapping[token])
+        raise KeyError(f"Token ({token}) not found in inverse mapping.")
+
+    def get_text(self, indices: Union[List[int], Tensor]) -> str:
+        if isinstance(indices, Tensor):
+            indices = indices.tolist()
+        return "".join([self.mapping[index] for index in indices])
+
+    def get_indices(self, text: str) -> Tensor:
+        return Tensor([self.inverse_mapping[token] for token in text])