userspace/libwr: add function to change order o bits in a portmask

Used by SNMP Signed-off-by: Michal Wasiak <michal.wasiak@gmail.com>

userspace/libwr: add function to change order o bits in a portmask
Used by SNMP Signed-off-by: Michal Wasiak <michal.wasiak@gmail.com>
8886548b · Michal Wasiak · Adam Wujek · fea1d9ec · 8886548b · 8886548b
Commit 8886548b authored Oct 14, 2020 by Michal Wasiak Committed by Adam Wujek Oct 29, 2020
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util.h userspace/libwr/include/libwr/util.h +3 -0

util.c userspace/libwr/util.c +21 -0

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--- a/userspace/libwr/include/libwr/util.h
+++ b/userspace/libwr/include/libwr/util.h
@@ -30,4 +30,7 @@ void *create_map(unsigned long address, unsigned long size);
 /* Count bits in a unsigned int */
 unsigned int bitCount (unsigned int value);

+/* Convert bitmask of ports from notation used by RTU (lowest port on lowest bit)
+ * to notation used by SNMP (lowrst port, most significant bit) */
+void convert_portmask_to_snmp_bitmask(int nports, uint32_t port_mask, char *bitmask, size_t *snmp_bitmask_len);
 #endif /* __LIBWR_HW_UTIL_H */
--- a/userspace/libwr/util.c
+++ b/userspace/libwr/util.c
@@ -144,3 +144,24 @@ unsigned int bitCount (unsigned int value) {
 	return count;
 }

+/* Convert bitmask of ports from notation used by RTU (lowest port on lowest bit)
+ * to notation used by SNMP (lowrst port, most significant bit) */
+void convert_portmask_to_snmp_bitmask(int nports, uint32_t port_mask, char *bitmask, size_t *snmp_bitmask_len)
+{
+    int i;
+
+    /* round up number of ports to a number dividable by 8 */
+    nports = 8 * ((nports + 7) / 8);
+    for (i = 0; i < nports;i++){
+	*bitmask |= port_mask & 1;
+	port_mask >>= 1;
+	/* jump to next char */
+	if (i % 8 == 7) {
+	    bitmask++;
+	    *bitmask = 0;
+	}
+	*bitmask <<= 1;
+    }
+    /* count the number of bytes used */
+    *snmp_bitmask_len = nports / 8;
+}