add ota algorithm for device

1. effective "Differential Upgrade" patch algorithm with high compression rate
2. effective recovery algorithm support recovery firmware in blocks which has low memory consumption and wear-leveling strategies, especially suitable for embeded devices with low RAM.
3. add sample ota bootloader project, see:
board\TencentOS_tiny_EVB_MX_Plus\KEIL\ota\ota_bootloader_recovery
4. add sample application project for download firmware through http, see:
board\TencentOS_tiny_EVB_MX_Plus\KEIL\ota\ota_application_download_through_http
5. add sample application project for download firmware through qcloud explorer console, see:
board\TencentOS_tiny_EVB_MX_Plus\KEIL\ota\ota_application_download_through_qcloud_iot_explorer
6. an OTA markdown document is pending

components/ota/common/lzma/3rdparty/XzCrc64.c

@@ -0,0 +1,86 @@
+/* XzCrc64.c -- CRC64 calculation
+2017-05-23 : Igor Pavlov : Public domain */
+
+#include "Precomp.h"
+
+#include "XzCrc64.h"
+#include "CpuArch.h"
+
+#define kCrc64Poly UINT64_CONST(0xC96C5795D7870F42)
+
+#ifdef MY_CPU_LE
+  #define CRC64_NUM_TABLES 4
+#else
+  #define CRC64_NUM_TABLES 5
+  #define CRC_UINT64_SWAP(v) \
+      ((v >> 56) \
+    | ((v >> 40) & ((UInt64)0xFF <<  8)) \
+    | ((v >> 24) & ((UInt64)0xFF << 16)) \
+    | ((v >>  8) & ((UInt64)0xFF << 24)) \
+    | ((v <<  8) & ((UInt64)0xFF << 32)) \
+    | ((v << 24) & ((UInt64)0xFF << 40)) \
+    | ((v << 40) & ((UInt64)0xFF << 48)) \
+    | ((v << 56)))
+
+  UInt64 MY_FAST_CALL XzCrc64UpdateT1_BeT4(UInt64 v, const void *data, size_t size, const UInt64 *table);
+#endif
+
+#ifndef MY_CPU_BE
+  UInt64 MY_FAST_CALL XzCrc64UpdateT4(UInt64 v, const void *data, size_t size, const UInt64 *table);
+#endif
+
+typedef UInt64 (MY_FAST_CALL *CRC64_FUNC)(UInt64 v, const void *data, size_t size, const UInt64 *table);
+
+static CRC64_FUNC g_Crc64Update;
+UInt64 g_Crc64Table[256 * CRC64_NUM_TABLES];
+
+UInt64 MY_FAST_CALL Crc64Update(UInt64 v, const void *data, size_t size)
+{
+  return g_Crc64Update(v, data, size, g_Crc64Table);
+}
+
+UInt64 MY_FAST_CALL Crc64Calc(const void *data, size_t size)
+{
+  return g_Crc64Update(CRC64_INIT_VAL, data, size, g_Crc64Table) ^ CRC64_INIT_VAL;
+}
+
+void MY_FAST_CALL Crc64GenerateTable()
+{
+  UInt32 i;
+  for (i = 0; i < 256; i++)
+  {
+    UInt64 r = i;
+    unsigned j;
+    for (j = 0; j < 8; j++)
+      r = (r >> 1) ^ (kCrc64Poly & ((UInt64)0 - (r & 1)));
+    g_Crc64Table[i] = r;
+  }
+  for (i = 256; i < 256 * CRC64_NUM_TABLES; i++)
+  {
+    UInt64 r = g_Crc64Table[(size_t)i - 256];
+    g_Crc64Table[i] = g_Crc64Table[r & 0xFF] ^ (r >> 8);
+  }
+  
+  #ifdef MY_CPU_LE
+
+  g_Crc64Update = XzCrc64UpdateT4;
+
+  #else
+  {
+    #ifndef MY_CPU_BE
+    UInt32 k = 1;
+    if (*(const Byte *)&k == 1)
+      g_Crc64Update = XzCrc64UpdateT4;
+    else
+    #endif
+    {
+      for (i = 256 * CRC64_NUM_TABLES - 1; i >= 256; i--)
+      {
+        UInt64 x = g_Crc64Table[(size_t)i - 256];
+        g_Crc64Table[i] = CRC_UINT64_SWAP(x);
+      }
+      g_Crc64Update = XzCrc64UpdateT1_BeT4;
+    }
+  }
+  #endif
+}