[devam007]

Description of Change

Return -1 before hashing when the pattern is longer than the text. Previously,
the initial hash accessed characters beyond the text, and the unsigned length
subtraction could underflow. Add the required cstdint header for the existing
int64_t declarations and four assertions for overlong, empty and exact-match
inputs. The hash algorithm and other behavior are unchanged.

Validation

GCC 15.2 / C++17: 16,066 reference comparisons pass against std::string::find,
including exhaustive binary-alphabet texts through length seven and patterns
through length five. The overlong-pattern reproduction fails on the base with
libstdc++ assertions enabled. The CMake/Ninja target, source assertions and
git diff --check pass. Existing signedness warnings remain. This patch does not
redesign integer hashing or establish safety for arbitrarily long patterns.
Remote CI, clang-format and clang-tidy were not run locally.

• Read contribution guidelines and kept the change to one algorithm file
• Added regression assertions and verified existing examples
• Included the header needed by the existing integer type