Diff: net.cpp

Revision:

0:faa09bd4e6bf

Child:

2:849103b5a16d

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/net.cpp	Mon Jan 09 13:29:41 2017 +0000
@@ -0,0 +1,70 @@
+#include "mbed.h"
+
+int16_t NetToHost16(int16_t n)
+{
+    int16_t h;
+    
+    char* pn = (char*)&n;
+    char* ph = (char*)&h + 1;
+    
+    *ph = *pn; ph--; pn++; // 1<-0
+    *ph = *pn;             // 0<-1
+
+    return h;
+}
+
+int32_t NetToHost32(int32_t n)
+{
+    int32_t h;
+    
+    char* pn = (char*)&n;
+    char* ph = (char*)&h + 3;
+    
+    *ph = *pn; ph--; pn++; // 3<-0
+    *ph = *pn; ph--; pn++; // 2<-1
+    *ph = *pn; ph--; pn++; // 1<-2
+    *ph = *pn;             // 0<-3
+
+    return h;
+}
+int64_t NetToHost64(int64_t n)
+{
+    int64_t h;
+    
+    char* pn = (char*)&n;
+    char* ph = (char*)&h + 7;
+    
+    *ph = *pn; ph--; pn++; // 7<-0
+    *ph = *pn; ph--; pn++; // 6<-1
+    *ph = *pn; ph--; pn++; // 5<-2
+    *ph = *pn; ph--; pn++; // 4<-3
+    *ph = *pn; ph--; pn++; // 3<-4
+    *ph = *pn; ph--; pn++; // 2<-5
+    *ph = *pn; ph--; pn++; // 1<-6
+    *ph = *pn;             // 0<-7
+
+    return h;
+}
+uint16_t onesComplement(uint16_t start, int count, void* pData)
+{    
+    uint32_t sum = start;                               //Initialise the 32 bit accumulator with the last sum
+    uint16_t* p = (uint16_t*)pData;                     //Set up a 16 bit pointer for the data
+    
+    while(count > 1)
+    {
+        sum += *p++;                                    // Add each pair of bytes into 32 bit accumulator
+        count -= 2;
+    }
+    if(count) sum += * (uint8_t*) p;                    // Add left-over byte, if any
+    while (sum>>16) sum = (sum & 0xffff) + (sum >> 16); // Add any carries from the sum back into the sum to make it ones complement
+    return sum;
+}
+uint16_t NetCheckSumTwo(int count1, void* pData1, int count2, void* pData2)
+{
+    uint16_t sum = onesComplement(0, count1, pData1);
+    return ~onesComplement(sum, count2, pData2);
+}
+uint16_t NetCheckSum(int count, void* pData)
+{
+    return ~onesComplement(0, count, pData);
+}