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comparison PrivateQueue.c @ 4:8abcca1590b8

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Tested and working on full VMS test
author Me
date Wed, 30 Jun 2010 14:34:56 -0700
parents 85af604dee9b
children 174a7c2ca340
comparison
equal deleted inserted replaced
0:7202babe6f9e 1:d17692922bff
35 retQ->endOfData = &(retQ->startOfData[1023]); 35 retQ->endOfData = &(retQ->startOfData[1023]);
36 36
37 return retQ; 37 return retQ;
38 } 38 }
39 39
40 PrivQueueStruc* make_larger_PrivQ( PrivQueueStruc *Q ) 40
41 void
42 enlargePrivQ( PrivQueueStruc *Q )
41 { int oldSize, newSize; 43 { int oldSize, newSize;
42 void **oldStartOfData; 44 void **oldStartOfData;
43 45
44 oldSize = Q->endOfData - Q->startOfData; 46 oldSize = Q->endOfData - Q->startOfData;
45 newSize = 2 * oldSize; 47 newSize = 2 * oldSize;
48 free(oldStartOfData); 50 free(oldStartOfData);
49 51
50 Q->extractPos = &(Q->startOfData[0]); //side by side == empty 52 Q->extractPos = &(Q->startOfData[0]); //side by side == empty
51 Q->insertPos = &(Q->startOfData[1]); // so start pos's have to be 53 Q->insertPos = &(Q->startOfData[1]); // so start pos's have to be
52 Q->endOfData = &(Q->startOfData[newSize - 1]); 54 Q->endOfData = &(Q->startOfData[newSize - 1]);
53
54 return Q;
55 } 55 }
56 56
57 57
58 /*Returns NULL when queue is empty 58 /*Returns NULL when queue is empty
59 */ 59 */
60 void* readPrivQ( PrivQueueStruc* Q ) 60 void* readPrivQ( PrivQueueStruc* Q )
61 { void *out = 0; 61 { void *out = 0;
62 int startOfData = Q->startOfData; 62 void **startOfData = Q->startOfData;
63 int endOfData = Q->endOfData; 63 void **endOfData = Q->endOfData;
64 64
65 volatile int insertPos = Q->insertPos; 65 void **insertPos = Q->insertPos;
66 volatile int extractPos = Q->extractPos; 66 void **extractPos = Q->extractPos;
67 67
68 //if not empty -- extract just below insert when empty 68 //if not empty -- extract just below insert when empty
69 if( insertPos - extractPos != 1 && 69 if( insertPos - extractPos != 1 &&
70 !(extractPos == endOfData && insertPos == startOfData)) 70 !(extractPos == endOfData && insertPos == startOfData))
71 { //move before read 71 { //move before read
80 } 80 }
81 //Q is empty 81 //Q is empty
82 return NULL; 82 return NULL;
83 } 83 }
84 84
85
86 /*Expands the queue size automatically when it's full
87 */
88 void
89 writeAndEnlargePrivQ( void * in, PrivQueueStruc* Q )
90 {
91 void **startOfData = Q->startOfData;
92 void **endOfData = Q->endOfData;
93
94 void **insertPos = Q->insertPos;
95 void **extractPos = Q->extractPos;
96
97 tryAgain:
98 if( extractPos - insertPos != 1 &&
99 !(insertPos == endOfData && extractPos == startOfData))
100 { *(Q->insertPos) = in; //insert before move
101 if( insertPos == endOfData ) //write new pos exactly once, correctly
102 { Q->insertPos = startOfData;
103 }
104 else
105 { Q->insertPos++;
106 }
107 return;
108 }
109 //Q is full
110 enlargePrivQ( Q );
111 goto tryAgain;
112 }
113
114
85 /*Returns false when the queue was full. 115 /*Returns false when the queue was full.
86 * have option of calling make_larger_PrivQ to make more room, then try again 116 * have option of calling make_larger_PrivQ to make more room, then try again
87 */ 117 */
88 bool8 writePrivQ( void * in, PrivQueueStruc* Q ) 118 int writeAndFailPrivQ( void * in, PrivQueueStruc* Q )
89 { 119 {
90 int startOfData = Q->startOfData; 120 void **startOfData = Q->startOfData;
91 int endOfData = Q->endOfData; 121 void **endOfData = Q->endOfData;
92 122
93 volatile int insertPos = Q->insertPos; 123 void **insertPos = Q->insertPos;
94 volatile int extractPos = Q->extractPos; 124 void **extractPos = Q->extractPos;
95 125
96 if( extractPos - insertPos != 1 && 126 if( extractPos - insertPos != 1 &&
97 !(insertPos == endOfData && extractPos == startOfData)) 127 !(insertPos == endOfData && extractPos == startOfData))
98 { *(insertPos) = in; //insert before move 128 { *(Q->insertPos) = in; //insert before move
99 if( insertPos == endOfData ) //write new pos exactly once, correctly 129 if( insertPos == endOfData ) //write new pos exactly once, correctly
100 { Q->insertPos = startOfData; 130 { Q->insertPos = startOfData;
101 } 131 }
102 else 132 else
103 { Q->insertPos++; 133 { Q->insertPos++;
105 return TRUE; 135 return TRUE;
106 } 136 }
107 //Q is full 137 //Q is full
108 return FALSE; 138 return FALSE;
109 } 139 }
110