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);