diff options
| author | Peter Collingbourne <peter@pcc.me.uk> | 2017-12-19 23:33:16 +0000 |
|---|---|---|
| committer | Peter Collingbourne <peter@pcc.me.uk> | 2017-12-19 23:33:16 +0000 |
| commit | 4b54e0fc2abfe7b1fa48425d8e72eb6a146ba49c (patch) | |
| tree | 40ece12b92a02ed7a0f0e411487ccc54ae8105fa | |
| parent | 5638e7b9c4143cbef0f12405ce65bf7b1dd1c13d (diff) | |
libcxx: Fix for basic_stringbuf::seekoff() after r320604.
As a result of this change, the basic_stringbuf constructor that
takes a mode ends up leaving __hm_ set to 0, causing the comparison
"__hm_ - __str_.data() < __noff" in seekoff() to succeed, which caused
the function to incorrectly return -1. The fix is to account for the
possibility of __hm_ being 0 when computing the distance from __hm_
to the start of the string.
Differential Revision: https://reviews.llvm.org/D41319
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@321124 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | include/sstream | 5 | ||||
| -rw-r--r-- | test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/seekoff.pass.cpp | 24 |
2 files changed, 27 insertions, 2 deletions
diff --git a/include/sstream b/include/sstream index 34b0014c1..b01f47b68 100644 --- a/include/sstream +++ b/include/sstream @@ -577,6 +577,7 @@ basic_stringbuf<_CharT, _Traits, _Allocator>::seekoff(off_type __off, if ((__wch & (ios_base::in | ios_base::out)) == (ios_base::in | ios_base::out) && __way == ios_base::cur) return pos_type(-1); + const ptrdiff_t __hm = __hm_ == nullptr ? 0 : __hm_ - __str_.data(); off_type __noff; switch (__way) { @@ -590,13 +591,13 @@ basic_stringbuf<_CharT, _Traits, _Allocator>::seekoff(off_type __off, __noff = this->pptr() - this->pbase(); break; case ios_base::end: - __noff = __hm_ - __str_.data(); + __noff = __hm; break; default: return pos_type(-1); } __noff += __off; - if (__noff < 0 || __hm_ - __str_.data() < __noff) + if (__noff < 0 || __hm < __noff) return pos_type(-1); if (__noff != 0) { diff --git a/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/seekoff.pass.cpp b/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/seekoff.pass.cpp index 6d20db131..8ec69cb24 100644 --- a/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/seekoff.pass.cpp +++ b/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/seekoff.pass.cpp @@ -21,6 +21,30 @@ int main() { { + std::stringbuf sb(std::ios_base::in); + assert(sb.pubseekoff(3, std::ios_base::beg, std::ios_base::out) == -1); + assert(sb.pubseekoff(3, std::ios_base::cur, std::ios_base::out) == -1); + assert(sb.pubseekoff(-3, std::ios_base::end, std::ios_base::out) == -1); + assert(sb.pubseekoff(3, std::ios_base::beg, std::ios_base::in | std::ios_base::out) == -1); + assert(sb.pubseekoff(3, std::ios_base::cur, std::ios_base::in | std::ios_base::out) == -1); + assert(sb.pubseekoff(-3, std::ios_base::end, std::ios_base::in | std::ios_base::out) == -1); + assert(sb.pubseekoff(0, std::ios_base::beg, std::ios_base::in) == 0); + assert(sb.pubseekoff(0, std::ios_base::cur, std::ios_base::in) == 0); + assert(sb.pubseekoff(0, std::ios_base::end, std::ios_base::in) == 0); + } + { + std::stringbuf sb(std::ios_base::out); + assert(sb.pubseekoff(3, std::ios_base::beg, std::ios_base::in) == -1); + assert(sb.pubseekoff(3, std::ios_base::cur, std::ios_base::in) == -1); + assert(sb.pubseekoff(-3, std::ios_base::end, std::ios_base::in) == -1); + assert(sb.pubseekoff(3, std::ios_base::beg, std::ios_base::in | std::ios_base::out) == -1); + assert(sb.pubseekoff(3, std::ios_base::cur, std::ios_base::in | std::ios_base::out) == -1); + assert(sb.pubseekoff(-3, std::ios_base::end, std::ios_base::in | std::ios_base::out) == -1); + assert(sb.pubseekoff(0, std::ios_base::beg, std::ios_base::out) == 0); + assert(sb.pubseekoff(0, std::ios_base::cur, std::ios_base::out) == 0); + assert(sb.pubseekoff(0, std::ios_base::end, std::ios_base::out) == 0); + } + { std::stringbuf sb("0123456789", std::ios_base::in); assert(sb.pubseekoff(3, std::ios_base::beg, std::ios_base::out) == -1); assert(sb.pubseekoff(3, std::ios_base::cur, std::ios_base::out) == -1); |