Teach PQescapeByteaConn() to use hex format when the target connection is

to a server >= 8.5.  Per my proposal in discussion of hex-format patch.

diff --git a/src/interfaces/libpq/fe-exec.c b/src/interfaces/libpq/fe-exec.c
index f1318a4a942d1ffec46d7b5ffe3991d5f47a57f3..df9ece0c0c49f3a4f5e75bdc4789b06b7293caba 100644 (file)
--- a/src/interfaces/libpq/fe-exec.c
+++ b/src/interfaces/libpq/fe-exec.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/interfaces/libpq/fe-exec.c,v 1.204 2009/08/04 16:08:36 tgl Exp $
+ *   $PostgreSQL: pgsql/src/interfaces/libpq/fe-exec.c,v 1.205 2009/08/04 18:05:42 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -3058,23 +3058,52 @@ PQescapeString(char *to, const char *from, size_t length)
                                  static_std_strings);
 }
 
+
+/* HEX encoding support for bytea */
+static const char hextbl[] = "0123456789abcdef";
+
+static const int8 hexlookup[128] = {
+   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+   0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
+   -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+   -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+};
+
+static inline char
+get_hex(char c)
+{
+   int         res = -1;
+
+   if (c > 0 && c < 127)
+       res = hexlookup[(unsigned char) c];
+
+   return (char) res;
+}
+
+
 /*
  *     PQescapeBytea   - converts from binary string to the
  *     minimal encoding necessary to include the string in an SQL
  *     INSERT statement with a bytea type column as the target.
  *
- *     The following transformations are applied
+ *     We can use either hex or escape (traditional) encoding.
+ *     In escape mode, the following transformations are applied:
  *     '\0' == ASCII  0 == \000
  *     '\'' == ASCII 39 == ''
  *     '\\' == ASCII 92 == \\
  *     anything < 0x20, or > 0x7e ---> \ooo
  *                                     (where ooo is an octal expression)
+ *
  *     If not std_strings, all backslashes sent to the output are doubled.
  */
 static unsigned char *
 PQescapeByteaInternal(PGconn *conn,
                      const unsigned char *from, size_t from_length,
-                     size_t *to_length, bool std_strings)
+                     size_t *to_length, bool std_strings, bool use_hex)
 {
    const unsigned char *vp;
    unsigned char *rp;
@@ -3088,17 +3117,24 @@ PQescapeByteaInternal(PGconn *conn,
     */
    len = 1;
 
-   vp = from;
-   for (i = from_length; i > 0; i--, vp++)
+   if (use_hex)
    {
-       if (*vp < 0x20 || *vp > 0x7e)
-           len += bslash_len + 3;
-       else if (*vp == '\'')
-           len += 2;
-       else if (*vp == '\\')
-           len += bslash_len + bslash_len;
-       else
-           len++;
+       len += bslash_len + 1 + 2 * from_length;
+   }
+   else
+   {
+       vp = from;
+       for (i = from_length; i > 0; i--, vp++)
+       {
+           if (*vp < 0x20 || *vp > 0x7e)
+               len += bslash_len + 3;
+           else if (*vp == '\'')
+               len += 2;
+           else if (*vp == '\\')
+               len += bslash_len + bslash_len;
+           else
+               len++;
+       }
    }
 
    *to_length = len;
@@ -3111,26 +3147,39 @@ PQescapeByteaInternal(PGconn *conn,
        return NULL;
    }
 
+   if (use_hex)
+   {
+       if (!std_strings)
+           *rp++ = '\\';
+       *rp++ = '\\';
+       *rp++ = 'x';
+   }
+
    vp = from;
    for (i = from_length; i > 0; i--, vp++)
    {
-       if (*vp < 0x20 || *vp > 0x7e)
-       {
-           int         val = *vp;
+       unsigned char c = *vp;
 
+       if (use_hex)
+       {
+           *rp++ = hextbl[(c >> 4) & 0xF];
+           *rp++ = hextbl[c & 0xF];
+       }
+       else if (c < 0x20 || c > 0x7e)
+       {
            if (!std_strings)
                *rp++ = '\\';
            *rp++ = '\\';
-           *rp++ = (val >> 6) + '0';
-           *rp++ = ((val >> 3) & 07) + '0';
-           *rp++ = (val & 07) + '0';
+           *rp++ = (c >> 6) + '0';
+           *rp++ = ((c >> 3) & 07) + '0';
+           *rp++ = (c & 07) + '0';
        }
-       else if (*vp == '\'')
+       else if (c == '\'')
        {
            *rp++ = '\'';
            *rp++ = '\'';
        }
-       else if (*vp == '\\')
+       else if (c == '\\')
        {
            if (!std_strings)
            {
@@ -3141,7 +3190,7 @@ PQescapeByteaInternal(PGconn *conn,
            *rp++ = '\\';
        }
        else
-           *rp++ = *vp;
+           *rp++ = c;
    }
    *rp = '\0';
 
@@ -3156,37 +3205,16 @@ PQescapeByteaConn(PGconn *conn,
    if (!conn)
        return NULL;
    return PQescapeByteaInternal(conn, from, from_length, to_length,
-                                conn->std_strings);
+                                conn->std_strings,
+                                (conn->sversion >= 80500));
 }
 
 unsigned char *
 PQescapeBytea(const unsigned char *from, size_t from_length, size_t *to_length)
 {
    return PQescapeByteaInternal(NULL, from, from_length, to_length,
-                                static_std_strings);
-}
-
-
-static const int8 hexlookup[128] = {
-   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-   0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
-   -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-   -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-};
-
-static inline char
-get_hex(char c)
-{
-   int         res = -1;
-
-   if (c > 0 && c < 127)
-       res = hexlookup[(unsigned char) c];
-
-   return (char) res;
+                                static_std_strings,
+                                false /* can't use hex */ );
 }