summaryrefslogtreecommitdiffstats
path: root/sql-common/pack.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--sql-common/pack.c210
1 files changed, 210 insertions, 0 deletions
diff --git a/sql-common/pack.c b/sql-common/pack.c
new file mode 100644
index 00000000..de821f08
--- /dev/null
+++ b/sql-common/pack.c
@@ -0,0 +1,210 @@
+/* Copyright (c) 2000-2003, 2007 MySQL AB
+ Use is subject to license terms
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; version 2 of the License.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
+
+#include <my_global.h>
+#include <mysql_com.h>
+#include <mysql.h>
+
+/* Get the length of next field. Change parameter to point at fieldstart */
+ulong net_field_length(uchar **packet)
+{
+ reg1 uchar *pos= (uchar *)*packet;
+ if (*pos < 251)
+ {
+ (*packet)++;
+ return (ulong) *pos;
+ }
+ if (*pos == 251)
+ {
+ (*packet)++;
+ return NULL_LENGTH;
+ }
+ if (*pos == 252)
+ {
+ (*packet)+=3;
+ return (ulong) uint2korr(pos+1);
+ }
+ if (*pos == 253)
+ {
+ (*packet)+=4;
+ return (ulong) uint3korr(pos+1);
+ }
+ (*packet)+=9; /* Must be 254 when here */
+ return (ulong) uint4korr(pos+1);
+}
+
+/* The same as above but returns longlong */
+my_ulonglong net_field_length_ll(uchar **packet)
+{
+ uchar *pos= *packet;
+ if (*pos < 251)
+ {
+ (*packet)++;
+ return (my_ulonglong) *pos;
+ }
+ if (*pos == 251)
+ {
+ (*packet)++;
+ return (my_ulonglong) NULL_LENGTH;
+ }
+ if (*pos == 252)
+ {
+ (*packet)+=3;
+ return (my_ulonglong) uint2korr(pos+1);
+ }
+ if (*pos == 253)
+ {
+ (*packet)+=4;
+ return (my_ulonglong) uint3korr(pos+1);
+ }
+ DBUG_ASSERT(*pos == 254);
+ (*packet)+=9; /* Must be 254 when here */
+ return (my_ulonglong) uint8korr(pos+1);
+}
+
+my_ulonglong safe_net_field_length_ll(uchar **packet, size_t packet_len)
+{
+ uchar *pos= *packet;
+ if (packet_len < 1)
+ goto err;
+ if (*pos < 251)
+ {
+ (*packet)++;
+ return (my_ulonglong) *pos;
+ }
+ if (*pos == 251)
+ {
+ (*packet)++;
+ return (my_ulonglong) NULL_LENGTH;
+ }
+ if (*pos == 252)
+ {
+ if (packet_len < 3)
+ goto err;
+ (*packet)+=3;
+ return (my_ulonglong) uint2korr(pos+1);
+ }
+ if (*pos == 253)
+ {
+ if (packet_len < 4)
+ goto err;
+ (*packet)+=4;
+ return (my_ulonglong) uint3korr(pos+1);
+ }
+ if (packet_len < 9 || *pos != 254)
+ goto err;
+ (*packet)+=9;
+ return (my_ulonglong) uint8korr(pos+1);
+err:
+ *packet = NULL;
+ return 0;
+}
+
+/*
+ Store an integer with simple packing into a output package
+
+ SYNOPSIS
+ net_store_length()
+ packet Store the packed integer here
+ length integers to store
+
+ NOTES
+ This is mostly used to store lengths of strings.
+
+ RETURN
+ Position in 'packet' after the packed length
+*/
+
+uchar *net_store_length(uchar *packet, ulonglong length)
+{
+ if (length < 251)
+ {
+ *packet= (uchar) length;
+ return packet+1;
+ }
+ /* 251 is reserved for NULL */
+ if (length < 65536)
+ {
+ *packet++=252;
+ int2store(packet, (uint) length);
+ return packet+2;
+ }
+ if (length < 16777216)
+ {
+ *packet++=253;
+ int3store(packet, (ulong) length);
+ return packet+3;
+ }
+ *packet++=254;
+ int8store(packet,length);
+ return packet+8;
+}
+
+uchar *safe_net_store_length(uchar *packet, size_t packet_len, ulonglong length)
+{
+ if (length < 251)
+ {
+ if (packet_len < 1)
+ return NULL;
+ *packet= (uchar) length;
+ return packet+1;
+ }
+ /* 251 is reserved for NULL */
+ if (length < 65536)
+ {
+ if (packet_len < 3)
+ return NULL;
+ *packet++=252;
+ int2store(packet, (uint) length);
+ return packet+2;
+ }
+ if (length < 16777216)
+ {
+ if (packet_len < 4)
+ return NULL;
+ *packet++=253;
+ int3store(packet, (ulong) length);
+ return packet+3;
+ }
+ if (packet_len < 9)
+ return NULL;
+ *packet++=254;
+ int8store(packet,length);
+ return packet+8;
+}
+
+
+/**
+ The length of space required to store the resulting length-encoded integer
+ for the given number. This function can be used at places where one needs to
+ dynamically allocate the buffer for a given number to be stored as length-
+ encoded integer.
+
+ @param num [IN] the input number
+
+ @return length of buffer needed to store this number [1, 3, 4, 9].
+*/
+
+uint net_length_size(ulonglong num)
+{
+ if (num < (ulonglong) 251LL)
+ return 1;
+ if (num < (ulonglong) 65536LL)
+ return 3;
+ if (num < (ulonglong) 16777216LL)
+ return 4;
+ return 9;
+}