Added z85 codec to ZMQ API

* Removed redundant Z85 code and include files from project
* Simplified use of headers in test cases (now they all just use testutil.hpp)
* Export zmq_z85_encode() and zmq_z85_decode() in API
* Added man pages for these two functions

src/zmq_utils.cpp

@@ -19,14 +19,11 @@
 
 #include "platform.hpp"
 
-#include "../include/zmq_utils.h"
-
-#include <stdlib.h>
-
-#include "stdint.hpp"
 #include "clock.hpp"
 #include "err.hpp"
 #include "thread.hpp"
+#include <assert.h>
+#include "../include/zmq_utils.h"
 
 #if !defined ZMQ_HAVE_WINDOWS
 #include <unistd.h>
@@ -72,3 +69,87 @@ void zmq_threadclose(void* thread)
     pThread->stop();
     delete pThread;
 }
+
+//  Z85 codec, taken from 0MQ RFC project, implements RFC32 Z85 encoding
+
+//  Maps base 256 to base 85
+static char encoder [85 + 1] = {
+    "0123456789" "abcdefghij" "klmnopqrst" "uvwxyzABCD"
+    "EFGHIJKLMN" "OPQRSTUVWX" "YZ.-:+=^!/" "*?&<>()[]{" 
+    "}@%$#"
+};
+
+//  Maps base 85 to base 256
+//  We chop off lower 32 and higher 128 ranges
+static uint8_t decoder [96] = {
+    0x00, 0x44, 0x00, 0x54, 0x53, 0x52, 0x48, 0x00, 
+    0x4B, 0x4C, 0x46, 0x41, 0x00, 0x3F, 0x3E, 0x45, 
+    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 
+    0x08, 0x09, 0x40, 0x00, 0x49, 0x42, 0x4A, 0x47, 
+    0x51, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 
+    0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 
+    0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 
+    0x3B, 0x3C, 0x3D, 0x4D, 0x00, 0x4E, 0x43, 0x00, 
+    0x00, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 
+    0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 
+    0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 
+    0x21, 0x22, 0x23, 0x4F, 0x00, 0x50, 0x00, 0x00
+};
+
+//  --------------------------------------------------------------------------
+//  Encode a binary frame as a string; destination string MUST be at least
+//  size * 5 / 4 bytes long plus 1 byte for the null terminator. Returns
+//  dest. Size must be a multiple of 4.
+
+char *zmq_z85_encode (char *dest, uint8_t *data, size_t size)
+{
+    assert (size % 4 == 0);
+    unsigned int char_nbr = 0;
+    unsigned int byte_nbr = 0;
+    uint32_t value = 0;
+    while (byte_nbr < size) {
+        //  Accumulate value in base 256 (binary)
+        value = value * 256 + data [byte_nbr++];
+        if (byte_nbr % 4 == 0) {
+            //  Output value in base 85
+            unsigned int divisor = 85 * 85 * 85 * 85;
+            while (divisor) {
+                dest [char_nbr++] = encoder [value / divisor % 85];
+                divisor /= 85;
+            }
+            value = 0;
+        }
+    }
+    assert (char_nbr == size * 5 / 4);
+    dest [char_nbr] = 0;
+    return dest;
+}
+
+    
+//  --------------------------------------------------------------------------
+//  Decode an encoded string into a binary frame; dest must be at least
+//  strlen (string) * 4 / 5 bytes long. Returns dest. strlen (string) 
+//  must be a multiple of 5.
+
+uint8_t *zmq_z85_decode (uint8_t *dest, char *string)
+{
+    assert (strlen (string) % 5 == 0);
+    unsigned int byte_nbr = 0;
+    unsigned int char_nbr = 0;
+    uint32_t value = 0;
+    while (char_nbr < strlen (string)) {
+        //  Accumulate value in base 85
+        value = value * 85 + decoder [(uint8_t) string [char_nbr++] - 32];
+        if (char_nbr % 5 == 0) {
+            //  Output value in base 256
+            unsigned int divisor = 256 * 256 * 256;
+            while (divisor) {
+                dest [byte_nbr++] = value / divisor % 256;
+                divisor /= 256;
+            }
+            value = 0;
+        }
+    }
+    assert (byte_nbr == strlen (string) * 4 / 5);
+    return dest;
+}