* fix: when use the load model from memory mode, the RAM occupy is high

test=develop

* ligth mem reuse
test=develop

* fix cpplint
test=develop

test=develop

size_t is an unsigned integer, with a conversion rank
 larger than int, therefore in the following expression
 the int value was promoted to size_t, making it a
 subtraction of unsigned values. The result of such
 a subtraction is also an unsigned value.