aboutsummaryrefslogtreecommitdiff
path: root/libbutl/fdstream.mxx
diff options
context:
space:
mode:
authorBoris Kolpackov <boris@codesynthesis.com>2018-11-24 14:44:21 +0200
committerBoris Kolpackov <boris@codesynthesis.com>2018-11-24 14:44:21 +0200
commit90fbede55256cb672a67d8181b4f0435047d4e13 (patch)
tree912917cdd3034d906b8e026153e901405d9a8227 /libbutl/fdstream.mxx
parent582940c789fd767d9e8c09cb4147d48b596261be (diff)
Add fdtruncate(), fdseek(), file position to [io]fdstream ctors
Diffstat (limited to 'libbutl/fdstream.mxx')
-rw-r--r--libbutl/fdstream.mxx79
1 files changed, 60 insertions, 19 deletions
diff --git a/libbutl/fdstream.mxx b/libbutl/fdstream.mxx
index 440e637..2bb3807 100644
--- a/libbutl/fdstream.mxx
+++ b/libbutl/fdstream.mxx
@@ -106,15 +106,18 @@ LIBBUTL_MODEXPORT namespace butl
// Notes and limitations:
//
// - char only
- // - input or output but not both
+ // - input or output but not both (can use a union of two streams for that)
// - no support for put back
+ // - no support for tell[gp]()/seek[gp]() (but see non-standard tellg() and
+ // tellp() in fdbuf)
// - non-blocking file descriptor is supported only by showmanyc() function
// and only on POSIX
// - throws ios::failure in case of open()/read()/write()/close() errors
// - exception mask has at least badbit
// - after catching an exception caused by badbit the stream is no longer
- // used
- // - not movable, though can be easily supported
+ // usable
+ // - not movable, though can be easily supported (or not: there is no move
+ // constructor for istream/ostream in GCC 4.9)
// - passing to constructor auto_fd with a negative file descriptor is valid
// and results in the creation of an unopened object
//
@@ -122,7 +125,11 @@ LIBBUTL_MODEXPORT namespace butl
{
public:
fdbuf () = default;
- fdbuf (auto_fd&&);
+
+ // Unless specified, the current read/write position is assumed to
+ // be 0 (note: not queried).
+ //
+ fdbuf (auto_fd&&, std::uint64_t pos = 0);
// Before we invented auto_fd into fdstreams we keept fdbuf opened on
// faulty close attempt. Now fdbuf is always closed by close() function.
@@ -136,7 +143,7 @@ LIBBUTL_MODEXPORT namespace butl
release ();
void
- open (auto_fd&&);
+ open (auto_fd&&, std::uint64_t pos = 0);
bool
is_open () const {return fd_.get () >= 0;}
@@ -167,7 +174,7 @@ LIBBUTL_MODEXPORT namespace butl
// Return the (logical) position of the next byte to be read.
//
- uint64_t
+ std::uint64_t
tellg () const {return off_ - (egptr () - gptr ());}
private:
@@ -188,7 +195,7 @@ LIBBUTL_MODEXPORT namespace butl
// Return the (logical) position of the next byte to be written.
//
- uint64_t
+ std::uint64_t
tellp () const {return off_ + (pptr () - buf_);}
private:
@@ -197,7 +204,7 @@ LIBBUTL_MODEXPORT namespace butl
private:
auto_fd fd_;
- uint64_t off_;
+ std::uint64_t off_;
char buf_[8192];
bool non_blocking_ = false;
};
@@ -251,7 +258,7 @@ LIBBUTL_MODEXPORT namespace butl
binary = 0x40, // Set binary translation mode.
at_end = 0x80, // Seek to the end of stream immediately after open.
- none = 0 // Usefull when build the mode incrementally.
+ none = 0 // Usefull when building the mode incrementally.
};
inline fdopen_mode operator& (fdopen_mode, fdopen_mode);
@@ -263,8 +270,9 @@ LIBBUTL_MODEXPORT namespace butl
{
protected:
fdstream_base () = default;
- fdstream_base (auto_fd&& fd): buf_ (std::move (fd)) {}
- fdstream_base (auto_fd&&, fdstream_mode);
+ fdstream_base (auto_fd&& fd, std::uint64_t pos)
+ : buf_ (std::move (fd), pos) {}
+ fdstream_base (auto_fd&&, fdstream_mode, std::uint64_t);
public:
int
@@ -368,8 +376,14 @@ LIBBUTL_MODEXPORT namespace butl
ifdstream (iostate e = badbit | failbit);
explicit
- ifdstream (auto_fd&&, iostate e = badbit | failbit);
- ifdstream (auto_fd&&, fdstream_mode m, iostate e = badbit | failbit);
+ ifdstream (auto_fd&&,
+ iostate e = badbit | failbit,
+ std::uint64_t pos = 0);
+
+ ifdstream (auto_fd&&,
+ fdstream_mode m,
+ iostate e = badbit | failbit,
+ std::uint64_t pos = 0);
explicit
ifdstream (const char*,
@@ -419,12 +433,16 @@ LIBBUTL_MODEXPORT namespace butl
open (const path&, fdopen_mode);
void
- open (auto_fd&& fd) {buf_.open (std::move (fd)); clear ();}
+ open (auto_fd&& fd, std::uint64_t pos = 0)
+ {
+ buf_.open (std::move (fd), pos);
+ clear ();
+ }
void
- open (auto_fd&& fd, fdstream_mode m)
+ open (auto_fd&& fd, fdstream_mode m, std::uint64_t pos = 0)
{
- open (std::move (fd));
+ open (std::move (fd), pos);
skip_ = (m & fdstream_mode::skip) == fdstream_mode::skip;
}
@@ -464,8 +482,14 @@ LIBBUTL_MODEXPORT namespace butl
ofdstream (iostate e = badbit | failbit);
explicit
- ofdstream (auto_fd&&, iostate e = badbit | failbit);
- ofdstream (auto_fd&&, fdstream_mode m, iostate e = badbit | failbit);
+ ofdstream (auto_fd&&,
+ iostate e = badbit | failbit,
+ std::uint64_t pos = 0);
+
+ ofdstream (auto_fd&&,
+ fdstream_mode m,
+ iostate e = badbit | failbit,
+ std::uint64_t pos = 0);
explicit
ofdstream (const char*,
@@ -515,7 +539,11 @@ LIBBUTL_MODEXPORT namespace butl
open (const path&, fdopen_mode);
void
- open (auto_fd&& fd) {buf_.open (std::move (fd)); clear ();}
+ open (auto_fd&& fd, std::uint64_t pos = 0)
+ {
+ buf_.open (std::move (fd), pos);
+ clear ();
+ }
void close () {if (is_open ()) flush (); buf_.close ();}
auto_fd release ();
@@ -709,6 +737,19 @@ LIBBUTL_MODEXPORT namespace butl
LIBBUTL_SYMEXPORT fdpipe
fdopen_pipe (fdopen_mode = fdopen_mode::none);
+ // Seeking.
+ //
+ enum class fdseek_mode {set, cur, end};
+
+ LIBBUTL_SYMEXPORT std::uint64_t
+ fdseek (int, std::uint64_t, fdseek_mode);
+
+ // Truncate or expand the file to the specified size. Throw ios::failure on
+ // the underlying OS error.
+ //
+ LIBBUTL_SYMEXPORT void
+ fdtruncate (int, std::uint64_t);
+
// Test whether a file descriptor refers to a terminal. Throw ios::failure on
// the underlying OS error.
//