Use SQLT_NUM instead of SQLT_VNU OCI type due to inconsistent buffer lengths

The size returned by OCI into the bound rlen parameter of a SQLT_VNU buffer
does not include the additional length byte. This causes problems with images
that are shared across multiple statements in ODB, such as the object_id
image of containers.

2 files changed, 33 insertions, 43 deletions

diff --git a/odb/oracle/details/number.cxx b/odb/oracle/details/number.cxx
index e62894d..6c0a56c 100644
--- a/odb/oracle/details/number.cxx
+++ b/odb/oracle/details/number.cxx
@@ -16,38 +16,32 @@ namespace odb
   {
     namespace details
     {
-      // The VARNUM type's binary representation is made up of the following
+      // The NUMBER type's binary representation is made up of the following
       // bit fields, ordered in increasing memory address.
       //
-      // 000 to 007: The size of the binary representation, including the
-      //             exponent bits and the mantissa bits, but excluding these
-      //             length bits.
-      //
-      // 008 to 015: The base-100 exponent bits. The most significant bit is
+      // 000 to 007: The base-100 exponent bits. The most significant bit is
       //             the sign bit of the number, which is set for positive
       //             numbers and cleared for negative numbers. For positive
       //             numbers, the exponent has a bias of 65 added to it.
       //
-      // 016 to 175: The mantissa bits. Each byte of this field represents a
+      // 008 to 167: The mantissa bits. Each byte of this field represents a
       //             single base-100 value.
       //
       //
 
       long long
-      number_to_int64 (const char* b)
+      number_to_int64 (const char* b, size_t n)
       {
         // All bytes in the buffer are interpreted as unsigned.
         //
         const unsigned char* ub (reinterpret_cast<const unsigned char*> (b));
 
-        int n (ub[0]);
-
         // Zero is represented by zero significant bits and an exponent
         // set to 128.
         //
         if (n == 1)
         {
-          assert (ub[1] == 128);
+          assert (ub[0] == 128);
           return 0;
         }
 
@@ -55,21 +49,21 @@ namespace odb
 
         // Test the sign bit of the exponent.
         //
-        if ((ub[1] & 0x80) != 0)
+        if ((ub[0] & 0x80) != 0)
         {
           // The unbiased exponent of a positive number may be calculated as
-          // ub[1] - 128 - 65. For an integer, this is the order of magnitude
+          // ub[0 - 128 - 65. For an integer, this is the order of magnitude
           // of the number. Calculate the maximum weight, 100 ^ o, where o is
           // the order of magnitude of the number.
           //
           long long w (1);
 
-          for (size_t i (0), o (ub[1] - 193); i < o; ++i)
+          for (size_t i (0), o (ub[0] - 193); i < o; ++i)
             w *= 100;
 
           // Accumlate the sum of the significant base-100 terms.
           //
-          for (const unsigned char* m (ub + 2), *e (ub + 1 + n); m < e; ++m)
+          for (const unsigned char* m (ub + 1), *e (ub + n); m < e; ++m)
           {
             v += (*m - 1) * w;
             w /= 100;
@@ -78,20 +72,20 @@ namespace odb
         else
         {
           // The unbiased exponent of a negative number is calculated as
-          // (~ub[1] & 0x7F) - 193. For an integer, this is the order of
+          // (~ub[0] & 0x7F) - 193. For an integer, this is the order of
           // magnitude of the number. Calculate the maximum weight, 100 ^ o,
           // where o is the order of magnitude of the number.
           //
           long long w (1);
 
-          for (size_t i (0), o ((~ub[1] & 0x7F) - 65); i < o; ++i)
+          for (size_t i (0), o ((~ub[0] & 0x7F) - 65); i < o; ++i)
             w *= 100;
 
           // Accumulate the sum of the significant base-100 terms. Note that
           // negative values will have a terminator byte which is included
           // in the length. This is ignored.
           //
-          for (const unsigned char* m (ub + 2), *e (ub + n); m < e; ++m)
+          for (const unsigned char* m (ub + 1), *e (ub + n - 1); m < e; ++m)
           {
             v -= (101 - *m) * w;
             w /= 100;
@@ -104,7 +98,7 @@ namespace odb
       void
       int64_to_number (char* b, size_t& n, long long v)
       {
-        // We assume that b is long enough to contain a long long VARNUM
+        // We assume that b is long enough to contain a long long NUMBER
         // representation, that being 12 bytes.
         //
 
@@ -114,8 +108,8 @@ namespace odb
 
         if (v == 0)
         {
-          ub[0] = 1;
-          ub[1] = 128;
+          ub[0] = 128;
+          n = 1;
 
           return;
         }
@@ -145,7 +139,7 @@ namespace odb
           // The exponent is one less than the number of base 100 digits. It is
           // inverted for negative values.
           //
-          ub[1] = static_cast<unsigned char> (~(n + 192));
+          ub[0] = static_cast<unsigned char> (~(n + 192));
         }
         else
         {
@@ -163,36 +157,33 @@ namespace odb
 
           // Exponent is one less than the number of base 100 digits.
           //
-          ub[1] = static_cast<unsigned char> (n + 192);
+          ub[0] = static_cast<unsigned char> (n + 192);
         }
 
         // Set the length.
         //
-        ub[0] = static_cast<unsigned char> (m - t + 1);
-        n = static_cast<size_t> (ub[0] + 1);
+        n = static_cast<unsigned char> (m - t + 1);
 
         // Set the significant digits in big-endian byte order and the
         // terminator, if any.
         //
-        for (size_t i (2); m > t; ++i)
+        for (size_t i (1); m > t; ++i)
           ub[i] = *--m;
       }
 
       unsigned long long
-      number_to_uint64 (const char* b)
+      number_to_uint64 (const char* b, size_t n)
       {
         // All bytes in the buffer are interpreted as unsigned.
         //
         const unsigned char* ub (reinterpret_cast<const unsigned char*> (b));
 
-        int n (ub[0]);
-
         // Zero is represented by zero significant bits and an exponent
         // set to 128.
         //
         if (n == 1)
         {
-          assert (ub[1] == 128);
+          assert (ub[0] == 128);
           return 0;
         }
 
@@ -200,25 +191,25 @@ namespace odb
 
         // Test the sign bit of the exponent.
         //
-        if ((ub[1] & 0x80) == 0)
+        if ((ub[0] & 0x80) == 0)
         {
           assert (false);
           return 0;
         }
 
         // The unbiased exponent of a positive number may be calculated as
-        // ub[1] - 128 - 65. For an integer, this is the order of magnitude
+        // ub[0] - 128 - 65. For an integer, this is the order of magnitude
         // of the number. Calculate the maximum weight, 100 ^ o, where o is
         // the order of magnitude of the number.
         //
         unsigned long long w (1);
 
-        for (size_t i (0), o (ub[1] - 193); i < o; ++i)
+        for (size_t i (0), o (ub[0] - 193); i < o; ++i)
           w *= 100;
 
         // Accumlate the sum of the significant base-100 terms.
         //
-        for (const unsigned char* m (ub + 2), *e (ub + 1 + n); m < e; ++m)
+        for (const unsigned char* m (ub + 1), *e (ub + n); m < e; ++m)
         {
           v += (*m - 1) * w;
           w /= 100;
@@ -231,7 +222,7 @@ namespace odb
       uint64_to_number (char* b, size_t& n, unsigned long long v)
       {
         // We assume that b is long enough to contain an unsigned long long
-        // VARNUM representation, that being 12 bytes.
+        // NUMBER representation, that being 12 bytes.
         //
 
         // All bytes in the buffer are interpreted as unsigned.
@@ -240,8 +231,8 @@ namespace odb
 
         if (v == 0)
         {
-          ub[0] = 1;
-          ub[1] = 128;
+          ub[0] = 128;
+          n = 1;
 
           return;
         }
@@ -264,16 +255,15 @@ namespace odb
 
         // Exponent is one less than the number of base 100 digits.
         //
-        ub[1] = static_cast<unsigned char> (n + 192);
+        ub[0] = static_cast<unsigned char> (n + 192);
 
         // Set the length.
         //
-        ub[0] = static_cast<unsigned char> (m - t + 1);
-        n = static_cast<size_t> (ub[0] + 1);
+        n = static_cast<unsigned char> (m - t + 1);
 
         // Set the significant digits in big-endian byte order.
         //
-        for (size_t i (2); m > t; ++i)
+        for (size_t i (1); m > t; ++i)
           ub[i] = *--m;
       }
     }
diff --git a/odb/oracle/details/number.hxx b/odb/oracle/details/number.hxx
index 90fb038..3b10a3c 100644
--- a/odb/oracle/details/number.hxx
+++ b/odb/oracle/details/number.hxx
@@ -27,13 +27,13 @@ namespace odb
       using namespace odb::details;
 
       LIBODB_ORACLE_EXPORT long long
-      number_to_int64 (const char* buffer);
+      number_to_int64 (const char* buffer, std::size_t n);
 
       LIBODB_ORACLE_EXPORT void
       int64_to_number (char* buffer, std::size_t& n, long long val);
 
       LIBODB_ORACLE_EXPORT unsigned long long
-      number_to_uint64 (const char* buffer);
+      number_to_uint64 (const char* buffer, std::size_t n);
 
       LIBODB_ORACLE_EXPORT void
       uint64_to_number (char* buffer, std::size_t& n, unsigned long long val);