Initial commit of Roster

2025-06-28 01:12:46 -05:00
commit c23d3a7676
4367 changed files with 890519 additions and 0 deletions
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+#
+# RunLength decoder (Adobe version) implementation based on PDF Reference
+# version 1.4 section 3.3.4.
+#
+#  * public domain *
+#
+
+from typing import List
+
+
+def rldecode(data: bytes) -> bytes:
+    """RunLength decoder (Adobe version) implementation based on PDF Reference
+    version 1.4 section 3.3.4:
+        The RunLengthDecode filter decodes data that has been encoded in a
+        simple byte-oriented format based on run length. The encoded data
+        is a sequence of runs, where each run consists of a length byte
+        followed by 1 to 128 bytes of data. If the length byte is in the
+        range 0 to 127, the following length + 1 (1 to 128) bytes are
+        copied literally during decompression. If length is in the range
+        129 to 255, the following single byte is to be copied 257 - length
+        (2 to 128) times during decompression. A length value of 128
+        denotes EOD.
+    """
+    decoded_array: List[int] = []
+    data_iter = iter(data)
+
+    while True:
+        length = next(data_iter, 128)
+        if length == 128:
+            break
+
+        if 0 <= length < 128:
+            decoded_array.extend((next(data_iter) for _ in range(length + 1)))
+
+        if length > 128:
+            run = [next(data_iter)] * (257 - length)
+            decoded_array.extend(run)
+    return bytes(decoded_array)