Heap Buffer Over-read in skip_space

[JeffJerseyCow]

Within the function skip_spaces, js-lexer.c:218 – a buffer over-read occurs when looking for the bytes 0xe2 0x80 0xa9, paragraph separator, by attempting a read ahead. There is an assert on line 217 that would prevent this in debug mode. Is the idea to let bugs into release builds? Or is there an over-sight I’m not seeing?

[zherczeg]

In JerryScript it is the user responsibility to pass valid UTF8/CESU8 data to the engine. If the user does not trust the input, they can use jerry_is_valid_utf8_string and jerry_is_valid_cesu8_string to check it. If these functions returns with false, the user should trow an error.

Overall this is a performance optimization for trusted input.

[LaszloLango]

Fixed