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authorKaren Arutyunov <karen@codesynthesis.com>2020-05-23 23:33:57 +0300
committerBoris Kolpackov <boris@codesynthesis.com>2020-05-25 14:25:05 +0200
commit813c483a312e1b1b4fa5a02234009ec546a0cc8c (patch)
tree8cbe1568270f49fa13caf0ca92948695c8fac386
parent095beb64a0752317a9a1d9777284a6c9343417cc (diff)
Add putback depth char_scanner template parameter
-rw-r--r--libbutl/char-scanner.ixx52
-rw-r--r--libbutl/char-scanner.mxx12
-rw-r--r--libbutl/char-scanner.txx20
3 files changed, 42 insertions, 42 deletions
diff --git a/libbutl/char-scanner.ixx b/libbutl/char-scanner.ixx
index 7e9c4b0..57aefc2 100644
--- a/libbutl/char-scanner.ixx
+++ b/libbutl/char-scanner.ixx
@@ -3,36 +3,33 @@
namespace butl
{
- template <typename V>
- inline char_scanner<V>::
+ template <typename V, std::size_t N>
+ inline char_scanner<V, N>::
char_scanner (std::istream& is, bool crlf, std::uint64_t l, std::uint64_t p)
: char_scanner (is, validator_type (), crlf, l, p)
{
}
- template <typename V>
- inline auto char_scanner<V>::
+ template <typename V, std::size_t N>
+ inline auto char_scanner<V, N>::
peek (std::string& what) -> xchar
{
return peek (&what);
}
- template <typename V>
- inline auto char_scanner<V>::
+ template <typename V, std::size_t N>
+ inline auto char_scanner<V, N>::
peek () -> xchar
{
return peek (nullptr /* what */);
}
- template <typename V>
- inline auto char_scanner<V>::
+ template <typename V, std::size_t N>
+ inline auto char_scanner<V, N>::
get (std::string* what) -> xchar
{
- if (unget_)
- {
- unget_ = false;
- return ungetc_;
- }
+ if (ungetn_ != 0)
+ return ungetb_[--ungetn_];
else
{
xchar c (peek (what));
@@ -41,33 +38,34 @@ namespace butl
}
}
- template <typename V>
- inline auto char_scanner<V>::
+ template <typename V, std::size_t N>
+ inline auto char_scanner<V, N>::
get (std::string& what) -> xchar
{
return get (&what);
}
- template <typename V>
- inline auto char_scanner<V>::
+ template <typename V, std::size_t N>
+ inline auto char_scanner<V, N>::
get () -> xchar
{
return get (nullptr /* what */);
}
- template <typename V>
- inline void char_scanner<V>::
+ template <typename V, std::size_t N>
+ inline void char_scanner<V, N>::
unget (const xchar& c)
{
// Because iostream::unget cannot work once eos is reached, we have to
// provide our own implementation.
//
- unget_ = true;
- ungetc_ = c;
+ assert (ungetn_ != N); // Make sure the buffer is not filled.
+
+ ungetb_[ungetn_++] = c;
}
- template <typename V>
- inline auto char_scanner<V>::
+ template <typename V, std::size_t N>
+ inline auto char_scanner<V, N>::
peek_ () -> int_type
{
if (gptr_ != egptr_)
@@ -86,8 +84,8 @@ namespace butl
return r;
}
- template <typename V>
- inline void char_scanner<V>::
+ template <typename V, std::size_t N>
+ inline void char_scanner<V, N>::
get_ ()
{
int_type c;
@@ -106,8 +104,8 @@ namespace butl
save_->push_back (static_cast<char_type> (c));
}
- template <typename V>
- inline std::uint64_t char_scanner<V>::
+ template <typename V, std::size_t N>
+ inline std::uint64_t char_scanner<V, N>::
pos_ () const
{
return buf_ != nullptr ? buf_->tellg () : 0;
diff --git a/libbutl/char-scanner.mxx b/libbutl/char-scanner.mxx
index e57245b..60994cf 100644
--- a/libbutl/char-scanner.mxx
+++ b/libbutl/char-scanner.mxx
@@ -9,6 +9,7 @@
#ifndef __cpp_lib_modules_ts
#include <string> // char_traits
+#include <cstddef> // size_t
#include <cstdint> // uint64_t
#include <climits> // INT_*
#include <utility> // pair, make_pair()
@@ -46,11 +47,12 @@ LIBBUTL_MODEXPORT namespace butl
// Low-level character stream scanner. Normally used as a base for
// higher-level lexers.
//
- template <typename V = noop_validator>
+ template <typename V = noop_validator, std::size_t N = 1>
class char_scanner
{
public:
using validator_type = V;
+ static constexpr const std::size_t unget_depth = N;
// If the crlf argument is true, then recognize Windows newlines (0x0D
// 0x0A) and convert them to just '\n' (0x0A). Note that a standalone
@@ -119,7 +121,7 @@ LIBBUTL_MODEXPORT namespace butl
: char_type (0);
}
- xchar (int_type v,
+ xchar (int_type v = 0,
std::uint64_t l = 0,
std::uint64_t c = 0,
std::uint64_t p = 0)
@@ -247,10 +249,10 @@ LIBBUTL_MODEXPORT namespace butl
bool crlf_;
bool eos_ = false;
- bool unget_ = false;
- bool unpeek_ = false;
+ std::size_t ungetn_ = 0;
+ xchar ungetb_[N];
- xchar ungetc_ = '\0';
+ bool unpeek_ = false;
xchar unpeekc_ = '\0';
};
}
diff --git a/libbutl/char-scanner.txx b/libbutl/char-scanner.txx
index d4e2082..35edf42 100644
--- a/libbutl/char-scanner.txx
+++ b/libbutl/char-scanner.txx
@@ -7,8 +7,8 @@
namespace butl
{
- template <typename V>
- char_scanner<V>::
+ template <typename V, std::size_t N>
+ char_scanner<V, N>::
char_scanner (std::istream& is,
validator_type v,
bool crlf,
@@ -26,12 +26,12 @@ namespace butl
{
}
- template <typename V>
- auto char_scanner<V>::
+ template <typename V, std::size_t N>
+ auto char_scanner<V, N>::
peek (std::string* what) -> xchar
{
- if (unget_)
- return ungetc_;
+ if (ungetn_ > 0)
+ return ungetb_[ungetn_ - 1];
if (unpeek_)
return unpeekc_;
@@ -108,12 +108,12 @@ namespace butl
return xchar (v, line, column, position);
}
- template <typename V>
- void char_scanner<V>::
+ template <typename V, std::size_t N>
+ void char_scanner<V, N>::
get (const xchar& c)
{
- if (unget_)
- unget_ = false;
+ if (ungetn_ > 0)
+ --ungetn_;
else
{
if (unpeek_)