MEDIUM: pattern: The parse functions just return "struct pattern" without memory...

MEDIUM: pattern: The parse functions just return "struct pattern" without memory allocation

The pattern parse functions put the parsed result in a "struct pattern"
without memory allocation. If the pattern must reference the input data
without changes, the pattern point to the parsed string. If buffers are
needed to store translated data, it use th trash buffer. The indexation
function that allocate the memory later if it is needed.