Add routines to help with single-byte (internal) character type support.

diff --git a/src/backend/utils/adt/char.c b/src/backend/utils/adt/char.c
index aec4bf8b192f94ad96850b44c0bab97b4d9faa7c..e4b0c64090411c489da89ad84bc0010d3e452e15 100644 (file)
--- a/src/backend/utils/adt/char.c
+++ b/src/backend/utils/adt/char.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/utils/adt/char.c,v 1.19 1998/09/01 03:25:50 momjian Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/utils/adt/char.c,v 1.19.2.1 1998/12/14 00:13:55 thomas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -29,7 +29,7 @@ int32
 charin(char *ch)
 {
    if (ch == NULL)
-       return (int32) NULL;
+       return (int32) '\0';
    return (int32) *ch;
 }
 
@@ -153,3 +153,21 @@ cideq(int8 arg1, int8 arg2)
 {
    return arg1 == arg2;
 }
+
+int8
+text_char(text *arg1)
+{
+   return ((int8) *(VARDATA(arg1)));
+}
+
+text *
+char_text(int8 arg1)
+{
+   text *result;
+
+   result = palloc(VARHDRSZ+1);
+   VARSIZE(result) = VARHDRSZ+1;
+   *(VARDATA(result)) = arg1;
+
+   return result;
+}

diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index 4be36bbba82f8972e387763f1320c854a19cae45..38bd68907021c8a8bfafadc6a8bc51867d9f9f63 100644 (file)
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/utils/adt/varlena.c,v 1.44 1998/10/08 18:30:12 momjian Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/utils/adt/varlena.c,v 1.44.2.1 1998/12/14 00:13:56 thomas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -313,9 +313,8 @@ textcat(text *t1, text *t2)
  * - starting position (is one-based)
  * - string length
  *
- * If the starting position is zero or less, then return the entire string.
- * XXX Note that this may not be the right behavior:
- * if we are calculating the starting position we might want it to start at one.
+ * If the starting position is zero or less, then return from the start of the string
+ *  adjusting the length to be consistant with the "negative start" per SQL92.
  * If the length is less than zero, return the remaining string.
  *
  * Note that the arguments operate on octet length,
@@ -323,6 +322,9 @@ textcat(text *t1, text *t2)
  *
  * Added multi-byte support.
  * - Tatsuo Ishii 1998-4-21
+ * Changed behavior if starting position is less than one to conform to SQL92 behavior.
+ * Formerly returned the entire string; now returns a portion.
+ * - Thomas Lockhart 1998-12-10
  */
 text *
 text_substr(text *string, int32 m, int32 n)
@@ -336,7 +338,7 @@ text_substr(text *string, int32 m, int32 n)
 
 #endif
 
-   if ((string == (text *) NULL) || (m <= 0))
+   if (string == (text *) NULL)
        return string;
 
    len = VARSIZE(string) - VARHDRSZ;
@@ -344,19 +346,25 @@ text_substr(text *string, int32 m, int32 n)
    len = pg_mbstrlen_with_len(VARDATA(string), len);
 #endif
 
-   /* m will now become a zero-based starting position */
+   /* starting position after the end of the string? */
    if (m > len)
    {
-       m = 0;
+       m = 1;
        n = 0;
    }
-   else
+   /* starting position before the start of the string?
+    * then offset into the string per SQL92 spec... */
+   else if (m < 1)
    {
-       m--;
-       if (((m + n) > len) || (n < 0))
-           n = (len - m);
+       n += (m-1);
+       m = 1;
    }
 
+   /* m will now become a zero-based starting position */
+   m--;
+   if (((m + n) > len) || (n < 0))
+       n = (len - m);
+
 #ifdef MULTIBYTE
    p = VARDATA(string);
    for (i = 0; i < m; i++)