Snake string utils

tonsdk/boc/__init__.py

@@ -2,11 +2,13 @@
 from ._builder import Builder, begin_cell
 from ._dict_builder import DictBuilder, begin_dict
 from ._slice import Slice
+from ._string_utils import string_to_cell, cell_to_string, read_string_tail, write_string_tail
 
 __all__ = [
     'Cell', 'Slice',
     'Builder', 'begin_cell',
     'DictBuilder', 'begin_dict',
     'deserialize_cell_data',
     'parse_boc_header',
+    'string_to_cell', 'cell_to_string', 'read_string_tail', 'write_string_tail'
 ]

tonsdk/utils/_data.py

@@ -0,0 +1,54 @@
+# https://github.com/ton-blockchain/TEPs/blob/master/text/0064-token-data-standard.md#data-serialization
+from ctypes import Union
+
+from tonsdk.boc import begin_cell, Builder, Slice
+
+
+class SnakeData:
+    prefix = 0x00
+    prefix_len = 8
+
+    @classmethod
+    def write(cls, builder: Builder, data: Union[bytes, bytearray], prefixed=False):
+        if prefixed:
+            builder.store_uint(cls.prefix, cls.prefix_len)
+
+        # todo: implement data serialization logic to a given builder (now data is a bytes sequence)
+        # implementation example
+        builders = []
+
+        while len(data) > 0:
+            max_bytes = builder.builder_rembits >> 3
+            bits, data = data[:max_bytes], data[max_bytes:]
+
+            builder.store_bytes(bits)
+            builders.append(builder)
+
+            builder = begin_cell()
+
+        if len(builders) > 1:
+            last_builder = builders[-1]
+
+            for builder in reversed(builders[:-1]):
+                builder.store_ref(last_builder.end_cell())
+                last_builder = builder
+
+        return builders[0]
+
+    @classmethod
+    def read(cls, cs: Slice, prefixed=False):
+        data = bytearray()
+
+        if prefixed:
+            assert cs.preload_uint(cls.prefix_len) == cls.prefix
+
+        while True:
+            data.extend(cs.load_bytes(cs.slice_bits >> 3))
+
+            if cs.slice_refs > 0:
+                cs = cs.load_ref().begin_parse()
+                continue
+
+            break
+
+        return data