rename read_head() to peek()
change all unsigned char to u8
use u32 instead of unsigned int and int
change find_brace() type from int to u8
find_brace(): change int braces to s32 braces
code_write(): change len type from int to ssize_t
input_write(): change len type from int to ssize_t
output_show(): change i type from unsigned int to u32
coding style: add newlines after declarations and before returns