do not read more than there is in istream

niXman · Aug 20, 2021 · 7af7953 · 7af7953
1 parent 64844ad
commit 7af7953
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Showing 7 changed files with 40 additions and 10 deletions.
diff --git a/include/yas/count_streams.hpp b/include/yas/count_streams.hpp
@@ -44,14 +44,17 @@ namespace yas {
 /***************************************************************************/
 
 struct count_ostream {
+    count_ostream()
+        :total_size{}
+    {}
 
     template<typename T>
     std::size_t write(const T *, const std::size_t size) {
         total_size += size;
         return size;
     }
 
-    std::size_t total_size = 0;
+    std::size_t total_size;
 }; // struct null_ostream
 
 /***************************************************************************/

diff --git a/include/yas/detail/io/json_streams.hpp b/include/yas/detail/io/json_streams.hpp
@@ -207,15 +207,15 @@ struct json_istream {
 	template<typename T>
 	void read(T &v, __YAS_ENABLE_IF_IS_ANY_OF(T, std::int16_t, std::int32_t, std::int64_t)) {
 		char buf[sizeof(T)*4];
-		const std::size_t n = json_read_num(is, buf, sizeof(buf));
+		const std::size_t n = json_read_num(is, buf, (std::min)(sizeof(buf), is.available()));
 		v = Trait::template atoi<T>(buf, n);
 	}
 
 	// for unsigned 16/32/64 bits
 	template<typename T>
 	void read(T &v, __YAS_ENABLE_IF_IS_ANY_OF(T, std::uint16_t, std::uint32_t, std::uint64_t)) {
 		char buf[sizeof(T)*4];
-		const std::size_t n = json_read_num(is, buf, sizeof(buf));
+		const std::size_t n = json_read_num(is, buf, (std::min)(sizeof(buf), is.available()));
 
 		v = Trait::template atou<T>(buf, n);
 	}
@@ -229,7 +229,7 @@ struct json_istream {
 			is.getch();
 		}
 
-		const std::size_t n = json_read_double(is, buf, sizeof(buf));
+		const std::size_t n = json_read_double(is, buf, (std::min)(sizeof(buf), is.available()));
 
 		if ( is.peekch() == '\"' ) {
 			is.getch();
@@ -247,7 +247,7 @@ struct json_istream {
 			is.getch();
 		}
 
-		const std::size_t n = json_read_double(is, buf, sizeof(buf));
+		const std::size_t n = json_read_double(is, buf, (std::min)(sizeof(buf), is.available()));
 
 		if ( is.peekch() == '\"' ) {
 			is.getch();

diff --git a/include/yas/detail/tools/json_tools.hpp b/include/yas/detail/tools/json_tools.hpp
@@ -302,8 +302,6 @@ std::size_t json_read_num(Archive &ar, char *ptr, std::size_t size) {
         ++ptr;
     } while ( --size );
 
-    ar.ungetch(*ptr);
-
     return ptr-p;
 }
 
@@ -335,8 +333,6 @@ std::size_t json_read_double(Archive &ar, char *ptr, std::size_t size) {
         ++ptr;
     } while ( --size );
 
-    ar.ungetch(*ptr);
-
     return ptr-p;
 }
 

diff --git a/include/yas/file_streams.hpp b/include/yas/file_streams.hpp
@@ -122,11 +122,16 @@ struct file_istream {
 
     file_istream(const char *fname, std::size_t m = 0)
         :file(std::fopen(fname, "rb"))
+        ,fsize(0)
     {
         if ( !file ) {
             __YAS_THROW_ERROR_OPEN_FILE();
         }
 
+        std::fseek(file, 0, SEEK_END);
+        fsize = std::ftell(file);
+        std::fseek(file, 0, SEEK_SET);
+
         if ( m & file_nobuf ) {
             std::setvbuf(file, nullptr, _IONBF, 0);
         }
@@ -139,6 +144,9 @@ struct file_istream {
         return std::fread(ptr, 1, size, file);
     }
 
+    std::size_t available() const {
+        return fsize - std::ftell(file);
+    }
     bool empty() const { return peekch() == char(EOF); }
     char peekch() const {
         // TODO: optimize
@@ -152,6 +160,7 @@ struct file_istream {
 
 private:
     std::FILE *file;
+    std::size_t fsize;
 }; // struct file_istream
 
 /***************************************************************************/

diff --git a/include/yas/mem_streams.hpp b/include/yas/mem_streams.hpp
@@ -158,6 +158,7 @@ struct mem_istream {
         return avail;
     }
 
+    std::size_t available() const { return end-cur; }
     bool empty() const { return cur == end; }
     char peekch() const { return *cur; }
     char getch() { return *cur++; }

diff --git a/include/yas/std_streams.hpp b/include/yas/std_streams.hpp
@@ -74,19 +74,27 @@ struct std_istream_adapter {
 
     std_istream_adapter(std::istream &is)
         :is(is)
-    {}
+        ,fsize(0)
+    {
+        std::streampos pos = is.tellg();
+        is.seekg(0, std::ios::end);
+        fsize = is.tellg() - pos;
+        is.seekg(pos, std::ios::beg);
+    }
 
     std::size_t read(void *ptr, const std::size_t size) {
         return __YAS_SCAST(std::size_t, is.read(__YAS_SCAST(char*, ptr), size).gcount());
     }
 
+    std::size_t available() const { return fsize - is.tellg(); }
     bool empty() const { return is.peek() == EOF; }
     char peekch() const { return __YAS_SCAST(char, is.peek()); }
     char getch() { return __YAS_SCAST(char, is.get()); }
     void ungetch(char ch) { is.putback(ch); }
 
 private:
     std::istream &is;
+    std::size_t fsize;
 }; // struct std_istream
 
 /***************************************************************************/

diff --git a/tests/base/include/fundamental.hpp b/tests/base/include/fundamental.hpp
@@ -159,6 +159,19 @@ bool fundamental_test(std::ostream &log, const char *archive_type, const char *t
         }
     }
 
+    if ( archive_traits::oarchive_type::type() == yas::json ) {
+        yas::intrusive_buffer ibuf("1234", 2);
+
+        yas::mem_istream is(ibuf);
+        yas::json_iarchive<yas::mem_istream> ia(is);
+        int v = 0;
+        ia & v;
+        if ( v != 12 ) {
+            YAS_TEST_REPORT(log, archive_type, test_name);
+            return false;
+        }
+    }
+
     return true;
 }