uniqueid_stub.c

00001 // Copyright (c) Microsoft. All rights reserved.
00002 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
00003 
00004 #include <stdlib.h>
00005 #include <stdint.h>
00006 #include "azure_c_shared_utility/uniqueid.h"
00007 #include "azure_c_shared_utility/xlogging.h"
00008 #include <time.h>
00009 
00010 DEFINE_ENUM_STRINGS(UNIQUEID_RESULT, UNIQUEID_RESULT_VALUES);
00011 
00012 static const char tochar[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
00013 static void generate128BitUUID(unsigned char* arrayOfByte)
00014 {
00015     size_t arrayIndex;
00016 
00017     for (arrayIndex = 0; arrayIndex < 16; arrayIndex++)
00018     {
00019         arrayOfByte[arrayIndex] = (unsigned char)rand();
00020     }
00021 
00022     //
00023     // Stick in the version field for random uuid.
00024     //
00025     arrayOfByte[7] &= 0x0f; //clear the bit field
00026     arrayOfByte[7] |= 0x40; //set the ones we care about
00027 
00028     //
00029     // Stick in the variant field for the random uuid.
00030     //
00031     arrayOfByte[8] &= 0xf3; // Clear
00032     arrayOfByte[8] |= 0x08; // Set
00033 
00034 }
00035 
00036 // TODO: The User will need to call srand before calling this function
00037 UNIQUEID_RESULT UniqueId_Generate(char* uid, size_t len)
00038 {
00039     UNIQUEID_RESULT result;
00040     unsigned char arrayOfChar[16];
00041 
00042     /* Codes_SRS_UNIQUEID_07_002: [If uid is NULL then UniqueId_Generate shall return UNIQUEID_INVALID_ARG] */
00043     /* Codes_SRS_UNIQUEID_07_003: [If len is less then 37 then UniqueId_Generate shall return UNIQUEID_INVALID_ARG] */
00044     if (uid == NULL || len < 37)
00045     {
00046         result = UNIQUEID_INVALID_ARG;
00047         LogError("Buffer Size is Null or length is less then 37 bytes");
00048     }
00049     else 
00050     {
00051         size_t arrayIndex;
00052         size_t shiftCount;
00053         size_t characterPosition = 0;
00054 
00055         /* Codes_SRS_UNIQUEID_07_001: [UniqueId_Generate shall create a unique Id 36 character long string.] */
00056         generate128BitUUID(arrayOfChar);
00057         for (arrayIndex = 0; arrayIndex < 16; arrayIndex++)
00058         {
00059             for (shiftCount = 0; shiftCount <= 1; shiftCount++)
00060             {
00061                 char hexChar = tochar[arrayOfChar[arrayIndex] & 0xf];
00062                 if ((characterPosition == 8) || (characterPosition == 13) || (characterPosition == 18) || (characterPosition == 23))
00063                 {
00064                     uid[characterPosition] = '-';
00065                     characterPosition++;
00066                 }
00067                 uid[characterPosition] = hexChar;
00068                 characterPosition++;
00069                 arrayOfChar[arrayIndex] = arrayOfChar[arrayIndex] >> 4;
00070             }
00071         }
00072         uid[characterPosition] = 0;
00073         result = UNIQUEID_OK;
00074     }
00075     return result;
00076 }