Diff: UUEncode.cpp

Revision:

0:15536fa79743

Child:

2:9e3ee0c6536b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/UUEncode.cpp	Tue Sep 27 15:44:55 2011 +0000
@@ -0,0 +1,135 @@
+#include "mbed.h"
+#include "LPC.h"
+
+//ENCODING FUNCTIONS BELOW
+int SerialBuffered::UUEncode() {       //Encodes the next 45 bytes in the file into a UUEncoded string with checksum and LF/CR characters ready to be sent to the board
+    int loop=0;  int i;  checksum=0;
+    for (int a=0; a<=63; a++) uuline[a]=0;
+    for (i=0; i<15; i++) {
+        if ((ch1=fgetc(f)) == EOF)  //Padded with 0x00 making life easier when the end of the file is reached
+            ch1=0x00;
+        if ((ch2=fgetc(f)) == EOF)
+            ch2=0x00;
+        if ((ch3=fgetc(f)) == EOF)
+            ch3=0x00;
+        checksum +=3;
+        Encode3();
+        uuline[1+(loop*4)]=n1;
+        uuline[2+(loop*4)]=n2;
+        uuline[3+(loop*4)]=n3;
+        uuline[4+(loop*4)]=n4;
+        loop++;
+    }
+    lastByte = 62;
+    uuline[0] = checksum+32;
+    uuline[61] = 0x0D;
+    uuline[62] = 0x0A;
+    return 0;
+}
+
+int SerialBuffered:: Encode3() {   //Does the actual raw encoding. Laid out in a less compact way to explicitly show the process going on
+    n1 = 0, n2 = 0, n3 = 0, n4 = 0;
+    sum20 += ch1+ch2+ch3;
+    if ((ch1-128)>=0)   {ch1-=128;  n1+=32;}
+    if ((ch1-64)>=0)    {ch1-=64;   n1+=16;}
+    if ((ch1-32)>=0)    {ch1-=32;   n1+=8;}
+    if ((ch1-16)>=0)    {ch1-=16;   n1+=4;}
+    if ((ch1-8)>=0)     {ch1-=8;    n1+=2;}
+    if ((ch1-4)>=0)     {ch1-=4;    n1+=1;}
+
+    if ((ch1-2)>=0)     {ch1-=2;    n2+=32;}
+    if ((ch1-1)>=0)     {ch1-=1;    n2+=16;}
+    if ((ch2-128)>=0)   {ch2-=128;  n2+=8;}
+    if ((ch2-64)>=0)    {ch2-=64;   n2+=4;}
+    if ((ch2-32)>=0)    {ch2-=32;   n2+=2;}
+    if ((ch2-16)>=0)    {ch2-=16;   n2+=1;}
+
+    if ((ch2-8)>=0)     {ch2-=8;    n3+=32;}
+    if ((ch2-4)>=0)     {ch2-=4;    n3+=16;}
+    if ((ch2-2)>=0)     {ch2-=2;    n3+=8;}
+    if ((ch2-1)>=0)     {ch2-=1;    n3+=4;}
+    if ((ch3-128)>=0)   {ch3-=128;  n3+=2;}
+    if ((ch3-64)>=0)    {ch3-=64;   n3+=1;}
+
+    if ((ch3-32)>=0)    {ch3-=32;   n4+=32;}
+    if ((ch3-16)>=0)    {ch3-=16;   n4+=16;}
+    if ((ch3-8)>=0)     {ch3-=8;    n4+=8;}
+    if ((ch3-4)>=0)     {ch3-=4;    n4+=4;}
+    if ((ch3-2)>=0)     {ch3-=2;    n4+=2;}
+    if ((ch3-1)>=0)     {ch3-=1;    n4+=1;}
+
+    if (n1 == 0x00) n1=0x60;
+    else n1+=0x20;
+    if (n2 == 0x00) n2=0x60;
+    else n2+=0x20;
+    if (n3 == 0x00) n3=0x60;
+    else n3+=0x20;
+    if (n4 == 0x00) n4=0x60;
+    else n4+=0x20;
+    return 0;
+}
+
+int SerialBuffered::FirstEncode() {  //Function to add two's complement of the first 7 DWORDs into the space occupied by the 8th DWORD (DWORDs 1-8 should add to zero)
+    long int precheck = 0;
+    int a;
+    for (a=0; a<9; a++) {
+        ch1 = fgetc(f);  ch2 = fgetc(f);     ch3 = fgetc(f);
+        sum[a*3]=ch1;    sum[(a*3)+1]=ch2;   sum[(a*3)+2]=ch3;
+    }
+    ch1 = fgetc(f);  fgetc(f);  fgetc(f);  fgetc(f);  fgetc(f);  //Ignores the 4 bytes which are to be overwritten
+    sum[27] = ch1;
+    
+    for (a=0; a<7; a++) {
+        sum1[a*4] = sum[a*4+3];
+        sum1[a*4+1] = sum[a*4+2];
+        sum1[a*4+2] = sum[a*4+1];
+        sum1[a*4+3] = sum[a*4];
+        precheck += (sum1[a*4]*0x1000000) + (sum1[a*4+1]*0x10000) + (sum1[a*4+2]*0x100) + sum1[a*4+3];
+    }
+    precheck = ~precheck+1;  //Takes the two's complement of the checksum
+    sum[28] = precheck & 0xFF;
+    sum[29] = (precheck >> 8) & 0xFF;
+    sum[30] = (precheck >>16) & 0xFF;
+    sum[31] = (precheck >>24) & 0xFF;
+    sum[32] = fgetc(f);
+    for (int a=33; a<46; a++) sum[a] = fgetc(f);
+    fseek(f, 0, SEEK_END);
+    filesize = ftell(f);
+    fclose(f);
+    f=fopen("/fs/delete.bin", "w");   //Opens a temporary file for writing to
+    fwrite (sum, 1, sizeof(sum), f);  //Writes the checksum-added and encoded bytes
+    fclose(f);
+    f=fopen("/fs/delete.bin", "r");   //Opens the original binary file again for reading
+    UUEncode();  
+    return 0;
+}
+
+int SerialBuffered::EndUUEncode() {  //Encodes the last 124 bytes of a 1024 byte block
+    int loop=0;  int i;  checksum=0;
+    for (int a=0; a<=50; a++) enduuline[a]=0;
+    for (i=1; i<=12; i++) {
+        if ((ch1=fgetc(f)) == EOF)
+            ch1=0x00;
+        if ((ch2=fgetc(f)) == EOF)
+            ch2=0x00;
+        if ((ch3=fgetc(f)) == EOF)
+            ch3=0x00;
+        checksum +=3;
+        if (loop==11) {
+            checksum-=2;
+            fseek (f, -2, SEEK_CUR);
+            ch2=0x00; ch3=0x00;
+        }
+        Encode3();
+        enduuline[1+(loop*4)]=n1;
+        enduuline[2+(loop*4)]=n2;
+        enduuline[3+(loop*4)]=n3;
+        enduuline[4+(loop*4)]=n4;
+        loop++;
+    }
+    lastByte = 51;
+    enduuline[0] = checksum+32;
+    enduuline[49] = 0x0D;
+    enduuline[50] = 0x0A;
+    return 0;
+}
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