Requiring contiguous buffers removes the need to use mxs::Buffer which
also removes the need to check for buffer boundaries.
Converted all the functions used by get_canonical into `static inline` so
that the compiler knows it can inline them. A few of them weren't `static`
which made the calls to the functions unnecessarily expensive.
The backslash was added instead of assigned. Since the value stored at
that position is always a null byte, assignment and addition would result
in the same outcome.
Requiring contiguous buffers removes the need to use mxs::Buffer which
also removes the need to check for buffer boundaries.
Converted all the functions used by get_canonical into `static inline` so
that the compiler knows it can inline them. A few of them weren't `static`
which made the calls to the functions unnecessarily expensive.
The backslash was added instead of assigned. Since the value stored at
that position is always a null byte, assignment and addition would result
in the same outcome.
A GWBUF given to any gwbuf-function:
- Must not be NULL. Exceptions are gwbuf_free() and gwbuf_append(),
in analogy with free() and realloc() respectively.
- Must be the head of a chain.
- Must be owned by the calling thread.
The process of appending to a std::string always includes a size check in
case the internal storage needs to expand. Given that we know a
canonicalized version of a query string is never larger than the original
string and that we pre-allocate enough memory to cope with the worst-case
scenario, the extra logic in std::string::push_back is unnecessary and an
extra cost. Writing directly into the string avoids this cost and improves
the performance.
Switched from default character type functions to ones that use lookup
tables. Eliminated the internal state and replaced with in-place iteration
of the query. Added code to allow single-lookup detection of normal
characters.
Since we know the worst-case size of a canonical statement is the size of
the query string, we can reduce the number of memory allocations to one in
the get_canonical function.
