Remove unnecessary string null-termination in pg_convert.

We can directly verify the unterminated input with pg_verify_mbstr_len.

diff --git a/src/backend/utils/mb/mbutils.c b/src/backend/utils/mb/mbutils.c
index a9dc2dee45cc884d088bf63a5b6bbba57e7284e9..a04181286af62d90ce983eb5056f3e7e00941642 100644 (file)
--- a/src/backend/utils/mb/mbutils.c
+++ b/src/backend/utils/mb/mbutils.c
@@ -406,14 +406,14 @@ pg_convert_from(PG_FUNCTION_ARGS)
 Datum
 pg_convert(PG_FUNCTION_ARGS)
 {
-   bytea      *string = PG_GETARG_BYTEA_P(0);
+   bytea      *string = PG_GETARG_BYTEA_PP(0);
    char       *src_encoding_name = NameStr(*PG_GETARG_NAME(1));
    int         src_encoding = pg_char_to_encoding(src_encoding_name);
    char       *dest_encoding_name = NameStr(*PG_GETARG_NAME(2));
    int         dest_encoding = pg_char_to_encoding(dest_encoding_name);
-   unsigned char *result;
+   const char *src_str;
+   char       *dest_str;
    bytea      *retval;
-   unsigned char *str;
    int         len;
 
    if (src_encoding < 0)
@@ -427,26 +427,25 @@ pg_convert(PG_FUNCTION_ARGS)
                 errmsg("invalid destination encoding name \"%s\"",
                        dest_encoding_name)));
 
-   /* make sure that source string is valid and null terminated */
-   len = VARSIZE(string) - VARHDRSZ;
-   pg_verify_mbstr(src_encoding, VARDATA(string), len, false);
-   str = palloc(len + 1);
-   memcpy(str, VARDATA(string), len);
-   *(str + len) = '\0';
+   /* make sure that source string is valid */
+   len = VARSIZE_ANY_EXHDR(string);
+   src_str = VARDATA_ANY(string);
+   pg_verify_mbstr_len(src_encoding, src_str, len, false);
 
-   result = pg_do_encoding_conversion(str, len, src_encoding, dest_encoding);
+   dest_str = (char *) pg_do_encoding_conversion(
+               (unsigned char *) src_str, len, src_encoding, dest_encoding);
+   if (dest_str != src_str)
+       len = strlen(dest_str);
 
    /*
     * build bytea data type structure.
     */
-   len = strlen((char *) result) + VARHDRSZ;
-   retval = palloc(len);
-   SET_VARSIZE(retval, len);
-   memcpy(VARDATA(retval), result, len - VARHDRSZ);
-
-   if (result != str)
-       pfree(result);
-   pfree(str);
+   retval = (bytea *) palloc(len + VARHDRSZ);
+   SET_VARSIZE(retval, len + VARHDRSZ);
+   memcpy(VARDATA(retval), dest_str, len);
+
+   if (dest_str != src_str)
+       pfree(dest_str);
 
    /* free memory if allocated by the toaster */
    PG_FREE_IF_COPY(string, 0);