diff options
| -rw-r--r-- | src/common/utils.c | 43 | ||||
| -rw-r--r-- | src/common/utils.h | 3 |
2 files changed, 46 insertions, 0 deletions
diff --git a/src/common/utils.c b/src/common/utils.c index dcf0a749a..73df3aae1 100644 --- a/src/common/utils.c +++ b/src/common/utils.c @@ -25,6 +25,7 @@ #include "common/cbasetypes.h" #include "common/core.h" #include "common/mmo.h" +#include "common/nullpo.h" #include "common/showmsg.h" #include "common/socket.h" #include "common/strlib.h" @@ -352,6 +353,48 @@ unsigned int get_percentage(const unsigned int A, const unsigned int B) return (unsigned int)floor(result); } +/** + * Applies a percentual rate modifier. + * + * @param value The base value. + * @param rate The rate modifier to apply. + * @param stdrate The rate modifier's divider (rate == stdrate => 100%). + * @return The modified value. + */ +int64 apply_percentrate64(int64 value, int rate, int stdrate) +{ + Assert_ret(stdrate > 0); + Assert_ret(rate >= 0); + if (rate == stdrate) + return value; + if (rate == 0) + return 0; + if (INT64_MAX / rate < value) { + // Give up some precision to prevent overflows + return value / stdrate * rate; + } + return value * rate / stdrate; +} + +/** + * Applies a percentual rate modifier. + * + * @param value The base value. + * @param rate The rate modifier to apply. Must be <= maxrate. + * @param maxrate The rate modifier's divider (maxrate = 100%). + * @return The modified value. + */ +int apply_percentrate(int value, int rate, int maxrate) +{ + Assert_ret(maxrate > 0); + Assert_ret(rate >= 0); + if (rate == maxrate) + return value; + if (rate == 0) + return 0; + return (int)(value * (int64)rate / maxrate); +} + //----------------------------------------------------- // custom timestamp formatting (from eApp) //----------------------------------------------------- diff --git a/src/common/utils.h b/src/common/utils.h index da2a29317..3f181ef12 100644 --- a/src/common/utils.h +++ b/src/common/utils.h @@ -42,6 +42,9 @@ bool exists(const char* filename); /// calculates the value of A / B, in percent (rounded down) unsigned int get_percentage(const unsigned int A, const unsigned int B); +int64 apply_percentrate64(int64 value, int rate, int maxrate); +int apply_percentrate(int value, int rate, int maxrate); + const char* timestamp2string(char* str, size_t size, time_t timestamp, const char* format); ////////////////////////////////////////////////////////////////////////// |