Coverage for /pythoncovmergedfiles/medio/medio/src/pdfminer.six/pdfminer/runlength.py: 6%

1# 

2# RunLength decoder (Adobe version) implementation based on PDF Reference 

3# version 1.4 section 3.3.4. 

4# 

5# * public domain * 

6# 

7 

8 

9def rldecode(data: bytes) -> bytes: 

10 """RunLength decoder (Adobe version) implementation based on PDF Reference 

11 version 1.4 section 3.3.4: 

12 The RunLengthDecode filter decodes data that has been encoded in a 

13 simple byte-oriented format based on run length. The encoded data 

14 is a sequence of runs, where each run consists of a length byte 

15 followed by 1 to 128 bytes of data. If the length byte is in the 

16 range 0 to 127, the following length + 1 (1 to 128) bytes are 

17 copied literally during decompression. If length is in the range 

18 129 to 255, the following single byte is to be copied 257 - length 

19 (2 to 128) times during decompression. A length value of 128 

20 denotes EOD. 

21 """ 

22 decoded = b"" 

23 i = 0 

24 while i < len(data): 

25 length = data[i] 

26 if length == 128: 

27 break 

28 

29 if length >= 0 and length < 128: 

30 for j in range(i + 1, (i + 1) + (length + 1)): 

31 decoded += bytes((data[j],)) 

32 i = (i + 1) + (length + 1) 

33 

34 if length > 128: 

35 run = bytes((data[i + 1],)) * (257 - length) 

36 decoded += run 

37 i = (i + 1) + 1 

38 

39 return decoded