Tesseract: Some possible problems

[shlyakpavel]

1. Converting type 'int' to type 'BOOL8' can lead to a loss of high-order bits. Non-zero value can become 'FALSE'.
   https://github.com/tesseract-ocr/tesseract/blob/5fdaa479da2c52526dac1281871db5c4bdaff359/src/ccmain/paramsd.cpp#L160
2. The 'text' variable is assigned values twice successively. Perhaps this is a mistake.
   https://github.com/tesseract-ocr/tesseract/blob/2c044df95998bc52e70fbcc1a5f0a2c97b931408/src/ccmain/resultiterator.cpp#L593-L596
3. Division by zero
   https://github.com/tesseract-ocr/tesseract/blob/30081c517b70b2d298ed3532c8e06503668dbd9b/src/textord/makerow.cpp#L2326
   https://github.com/tesseract-ocr/tesseract/blob/30081c517b70b2d298ed3532c8e06503668dbd9b/src/textord/makerow.cpp#L2338

[amitdo]

What tool did you use to find these issues?

PVS Studio? Do you have a license for it or do you use the free license option?

[shlyakpavel]

@amitdo
Yes, it's PVS studio. I have a license)

[amitdo]

This is their new offering:
https://www.viva64.com/en/b/0600/

[stweil]

As far as I see only the 2nd points at a real problem.

[shlyakpavel]

@stweil why do you think division by zero is safe?

[stweil]

It's conditionally, and the condition is never true if the difference is 0 (unless there is a negative line_size which should never happen).

[shlyakpavel]

@stweil can you please explain the reason it is never true if the difference is 0?
It's not clear to me

[stweil]

The division is only executed if last_x - left_x > block->line_size * 2. A division by zero would occur if last_x - left_x == 0, that means only if 0 > block->line_size * 2 or rearranged block->line_size < 0.