Adding uudecode function

diff --git a/isp_utils.c b/isp_utils.c
index d44ec1f..4f9783f 100644 (file)
--- a/isp_utils.c
+++ b/isp_utils.c
@@ -19,12 +19,12 @@
 #include <fcntl.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <errno.h>
 
-#include <string.h>
+#include <string.h> /* memcpy */
 
-#include <termios.h>
+#include <termios.h> /* serial */
 #include <ctype.h>
-#include <errno.h>
 
 
 extern int trace_on;
@@ -183,7 +183,9 @@ int isp_serial_read(char* buf, unsigned int buf_size, unsigned int min_read)
 
 /* ---- UU_Encoding utility functions ----------------------------------------------*/
 
-/* FIXME : This is a place-holder forr uuencode and uudecode functions !!! */
+/* This might have been taken from a lib, but I hate lib dependencies, and installing
+ *  a full window manager (or MTA or MUA for instance) for two functions is not an 
+ *  option */
 int isp_uu_encode(char* dest, char* src, unsigned int orig_size)
 {
        int new_size = 0;
@@ -198,15 +200,54 @@ int isp_uu_encode(char* dest, char* src, unsigned int orig_size)
        return new_size;
 }
 
+#define UUENCODE_ADDED_VAL 32
+#define LINE_LENGTH_NULL 96
 int isp_uu_decode(char* dest, char* src, unsigned int orig_size)
 {
-       int new_size = 0;
-       while (orig_size--) {
-               if (*src) {
-                       *dest++ = *src++;
-               } else {
+       unsigned int new_size = 0;
+       unsigned int pos = 0;
+
+       while (pos < orig_size) {
+               unsigned int line_length = 0;
+               unsigned int i = 0;
+               int j = 0;
+
+               /* Read line length */
+               line_length = src[pos] - UUENCODE_ADDED_VAL;
+               if (src[pos] == LINE_LENGTH_NULL) {
+                       /* Empty line ? then we are done converting
+                        * (should not happen in communication with ISP) */
+                       return new_size;
+               }
+               pos++;
+
+               /* Decode line */
+               while (i < line_length) {
+                       char quartet[4];
+                       uint32_t int_triplet = 0;
+                       /* copy data */
+                       memcpy(quartet, &src[pos], 4);
+                       pos += 4;
+                       /* Get the original bits */
+                       for (j=0; j<4; j++) {
+                               /* Remove the offset added by uuencoding */
+                               quartet[j] -= UUENCODE_ADDED_VAL;
+                               int_triplet |= ((quartet[j] & 0x3F) << ((3 - j) * 6));
+                       }
+                       /* And store them */
+                       for (j=2; j>=0; j--) {
+                               dest[new_size++] = ((int_triplet >> (j * 8)) & 0xFF );
+                               i++;
+                               if (i >= line_length) {
+                                       break;
+                               }
+                       }
+               }
+               
+               /* Find next line */
+               while ((src[pos] < UUENCODE_ADDED_VAL) && (pos < orig_size))   {
+                       pos++;
                }
-               new_size++;
        }
        return new_size;
 }