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Commit 58bf572a authored by Nick Kralevich's avatar Nick Kralevich
Browse files

TypeHelpers.h: Don't underflow unsigned int 

When decrementing "n", eventually n will equal zero. When that
happens, n-- underflows. This causes a crash when code which uses
clang's -fsanitize=unsigned-integer-overflow is run.

Avoid trigging an unsigned integer underflow.

Change-Id: I9705be6580d61a164ef5fb1ec77e98a69d888438
parent 60c5a460

include/utils/TypeHelpers.h

+14 −7
Original line number Diff line number Diff line
@@ -131,7 +131,8 @@ int compare_type(const TYPE& lhs, const TYPE& rhs) { 
template<typename TYPE> inline

void construct_type(TYPE* p, size_t n) {

    if (!traits<TYPE>::has_trivial_ctor) {

        while (n--) {

        while (n > 0) {

            n--;

            new(p++) TYPE;

        }

    }
@@ -140,7 +141,8 @@ void construct_type(TYPE* p, size_t n) { 
template<typename TYPE> inline

void destroy_type(TYPE* p, size_t n) {

    if (!traits<TYPE>::has_trivial_dtor) {

        while (n--) {

        while (n > 0) {

            n--;

            p->~TYPE();

            p++;

        }
@@ -150,7 +152,8 @@ void destroy_type(TYPE* p, size_t n) { 
template<typename TYPE> inline

void copy_type(TYPE* d, const TYPE* s, size_t n) {

    if (!traits<TYPE>::has_trivial_copy) {

        while (n--) {

        while (n > 0) {

            n--;

            new(d) TYPE(*s);

            d++, s++;

        }
@@ -162,12 +165,14 @@ void copy_type(TYPE* d, const TYPE* s, size_t n) { 
template<typename TYPE> inline

void splat_type(TYPE* where, const TYPE* what, size_t n) {

    if (!traits<TYPE>::has_trivial_copy) {

        while (n--) {

        while (n > 0) {

            n--;

            new(where) TYPE(*what);

            where++;

        }

    } else {

        while (n--) {

        while (n > 0) {

            n--;

            *where++ = *what;

        }

    }
@@ -182,7 +187,8 @@ void move_forward_type(TYPE* d, const TYPE* s, size_t n = 1) { 
    } else {

        d += n;

        s += n;

        while (n--) {

        while (n > 0) {

            n--;

            --d, --s;

            if (!traits<TYPE>::has_trivial_copy) {

                new(d) TYPE(*s);
@@ -203,7 +209,8 @@ void move_backward_type(TYPE* d, const TYPE* s, size_t n = 1) { 
    {

        memmove(d,s,n*sizeof(TYPE));

    } else {

        while (n--) {

        while (n > 0) {

            n--;

            if (!traits<TYPE>::has_trivial_copy) {

                new(d) TYPE(*s);

            } else {