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annotate PrivateQueue.c @ 37:b9cb01d8ce56

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First working version
author Sean Halle <seanhalle@yahoo.com>
date Wed, 06 Jun 2012 18:00:59 -0700
parents 3f5e365143fd
children 8fcbe46de60a d01d48b023ca
rev   line source
Me@19 1 /*
Me@19 2 * Copyright 2009 OpenSourceStewardshipFoundation.org
Me@19 3 * Licensed under GNU General Public License version 2
Me@19 4 *
Me@19 5 * NOTE: this version of SRSW correct as of April 25, 2010
Me@19 6 *
Me@19 7 * Author: seanhalle@yahoo.com
Me@19 8 */
Me@19 9
Me@19 10
Me@19 11 #include <stdio.h>
Me@19 12 #include <string.h>
Me@19 13 #include <errno.h>
Me@19 14 #include <stdlib.h>
Me@19 15
Me@19 16 #include "PrivateQueue.h"
Me@19 17
Me@19 18
Me@19 19
Me@19 20 //===========================================================================
Me@19 21
Me@19 22 /*This kind of queue is private to a single core at a time -- has no
Me@19 23 * synchronizations
Me@19 24 */
Me@19 25
Me@19 26 PrivQueueStruc* makePrivQ()
Me@19 27 {
Me@19 28 PrivQueueStruc* retQ;
seanhalle@32 29 //This malloc is not safe to use in wrapper lib nor app code!
seanhalle@32 30 retQ = (PrivQueueStruc *) VMS_int__malloc( sizeof( PrivQueueStruc ) );
Me@19 31
seanhalle@32 32 //This malloc is not safe to use in wrapper lib nor app code!
seanhalle@37 33 retQ->startOfData = VMS_int__malloc( 1024 * sizeof(void *) );
Me@19 34 memset( retQ->startOfData, 0, 1024 * sizeof(void *) );
Me@19 35 retQ->extractPos = &(retQ->startOfData[0]); //side by side == empty
Me@19 36 retQ->insertPos = &(retQ->startOfData[1]); // so start pos's have to be
Me@19 37 retQ->endOfData = &(retQ->startOfData[1023]);
Me@19 38
Me@19 39 return retQ;
Me@19 40 }
Me@19 41
Me@19 42
Me@19 43 void
Me@19 44 enlargePrivQ( PrivQueueStruc *Q )
seanhalle@35 45 { int32 oldSize, newSize, topPartSize, bottPartSize;
seanhalle@32 46 int8 *insertPos, *extractPos;
seanhalle@32 47 int8 *oldStartOfData, *oldEndOfData, *newStartOfData, *newEndOfData;
seanhalle@35 48 int32 insertOffsetBytes, extractOffsetBytes;
seanhalle@35 49 int8 *copyStartAddr;
Me@19 50
seanhalle@32 51 oldStartOfData = (int8 *)Q->startOfData;
seanhalle@32 52 oldEndOfData = (int8 *)Q->endOfData;
seanhalle@32 53 insertPos = (int8 *)Q->insertPos;
seanhalle@32 54 extractPos = (int8 *)Q->extractPos;
Me@19 55
seanhalle@32 56 //TODO: verify these get number of bytes correct
seanhalle@35 57 insertOffsetBytes = (int32)(insertPos - oldStartOfData);
seanhalle@35 58 extractOffsetBytes = (int32)(extractPos - oldStartOfData);
seanhalle@32 59
seanhalle@35 60 oldSize = oldEndOfData - oldStartOfData + 1; //in bytes
seanhalle@32 61 newSize = 2 * oldSize;
seanhalle@32 62
seanhalle@32 63 //This malloc is not safe to use in wrapper lib nor app code!
seanhalle@32 64 Q->startOfData = (void **)VMS_int__malloc( newSize );
seanhalle@32 65 newStartOfData = (int8 *)Q->startOfData;
seanhalle@32 66 newEndOfData = newStartOfData + newSize; //all calcs in Bytes
seanhalle@32 67 Q->endOfData = (void **)newEndOfData;
seanhalle@32 68
seanhalle@32 69 //TODO: test all of this, for both cases
seanhalle@32 70
seanhalle@32 71 //Moving the data and pointers to the new array is
seanhalle@32 72 //a little trickier than at first it seems.. the top part
seanhalle@32 73 // of old queue must be moved to the top part of new queue, while
seanhalle@32 74 // bottom part of old to bottom part of new, then the new insert
seanhalle@32 75 // and extract positions calculated by offset from top and bottom
seanhalle@32 76 //UNLESS the one case where old extract was at bottom and insert
seanhalle@32 77 // was at top.
seanhalle@32 78 //TODO: check that this is correct!
seanhalle@35 79 if( extractPos == oldStartOfData && insertPos == oldEndOfData )
seanhalle@32 80 {
seanhalle@32 81 memcpy( newStartOfData, oldStartOfData, oldSize ); //oldSize is bytes
seanhalle@32 82 Q->extractPos = Q->startOfData; //start of valid data
seanhalle@32 83 Q->insertPos = Q->startOfData + oldSize - 1; //end of valid data
seanhalle@32 84 }
seanhalle@32 85 else //have to copy two parts separately, then calc positions
seanhalle@32 86 { //TODO: check end-addr, sizes, and new positions carefully
seanhalle@35 87
seanhalle@32 88 //copy top part, starting at extract up until end of data,
seanhalle@35 89 // into top of new array
seanhalle@32 90 topPartSize = oldEndOfData - extractPos + 1; //+1 includes extractPos
seanhalle@35 91 copyStartAddr = newEndOfData - topPartSize + 1;//+1 cancels other
seanhalle@32 92 memcpy( copyStartAddr, Q->extractPos, topPartSize );
seanhalle@35 93 Q->extractPos = (void **)copyStartAddr; //extract just-copied data
seanhalle@35 94
seanhalle@32 95 //copy bottom part, from old start up to old insert,
seanhalle@35 96 // into bottom of new array
seanhalle@32 97 bottPartSize = oldSize - topPartSize - 1; //-1 for empty insertPos
seanhalle@32 98 memcpy( newStartOfData, oldStartOfData, bottPartSize );
seanhalle@32 99 Q->insertPos = (void **)(newStartOfData + bottPartSize);
seanhalle@32 100 }
seanhalle@32 101 //This free is not safe to use in wrapper lib nor app code!
seanhalle@32 102 VMS_int__free(oldStartOfData);
Me@19 103 }
Me@19 104
Me@19 105
seanhalle@37 106 /*Returns TRUE when queue is empty
seanhalle@37 107 */
seanhalle@37 108 bool32 isEmptyPrivQ( PrivQueueStruc* Q )
seanhalle@37 109 { void *out = 0;
seanhalle@37 110 void **startOfData = Q->startOfData;
seanhalle@37 111 void **endOfData = Q->endOfData;
seanhalle@37 112
seanhalle@37 113 void **insertPos = Q->insertPos;
seanhalle@37 114 void **extractPos = Q->extractPos;
seanhalle@37 115
seanhalle@37 116 //if not empty -- (extract is just below insert when empty)
seanhalle@37 117 if( insertPos - extractPos != 1 &&
seanhalle@37 118 !(extractPos == endOfData && insertPos == startOfData))
seanhalle@37 119 {
seanhalle@37 120 return FALSE;
seanhalle@37 121 }
seanhalle@37 122 //Q is empty
seanhalle@37 123 return TRUE;
seanhalle@37 124 }
seanhalle@37 125
seanhalle@37 126 /*Returns NULL when queue is empty
seanhalle@37 127 */
seanhalle@37 128 void* peekPrivQ( PrivQueueStruc* Q )
seanhalle@37 129 { void *out = 0;
seanhalle@37 130 void **startOfData = Q->startOfData;
seanhalle@37 131 void **endOfData = Q->endOfData;
seanhalle@37 132
seanhalle@37 133 void **insertPos = Q->insertPos;
seanhalle@37 134 void **extractPos = Q->extractPos;
seanhalle@37 135
seanhalle@37 136 //if not empty -- (extract is just below insert when empty)
seanhalle@37 137 if( insertPos - extractPos != 1 &&
seanhalle@37 138 !(extractPos == endOfData && insertPos == startOfData))
seanhalle@37 139 {
seanhalle@37 140 out = *(Q->extractPos);
seanhalle@37 141 return out;
seanhalle@37 142 }
seanhalle@37 143 //Q is empty
seanhalle@37 144 return NULL;
seanhalle@37 145 }
seanhalle@37 146
seanhalle@37 147
Me@19 148 /*Returns NULL when queue is empty
Me@19 149 */
Me@19 150 void* readPrivQ( PrivQueueStruc* Q )
Me@19 151 { void *out = 0;
Me@19 152 void **startOfData = Q->startOfData;
Me@19 153 void **endOfData = Q->endOfData;
Me@19 154
Me@19 155 void **insertPos = Q->insertPos;
Me@19 156 void **extractPos = Q->extractPos;
Me@19 157
Me@19 158 //if not empty -- (extract is just below insert when empty)
Me@19 159 if( insertPos - extractPos != 1 &&
Me@19 160 !(extractPos == endOfData && insertPos == startOfData))
Me@19 161 { //move before read
Me@19 162 if( extractPos == endOfData ) //write new pos exactly once, correctly
Me@19 163 { Q->extractPos = startOfData; //can't overrun then fix it 'cause
Me@19 164 } // other thread might read bad pos
Me@19 165 else
Me@19 166 { Q->extractPos++;
Me@19 167 }
Me@19 168 out = *(Q->extractPos);
Me@19 169 return out;
Me@19 170 }
Me@19 171 //Q is empty
Me@19 172 return NULL;
Me@19 173 }
Me@19 174
Me@19 175
Me@19 176 /*Expands the queue size automatically when it's full
Me@19 177 */
Me@19 178 void
Me@19 179 writePrivQ( void * in, PrivQueueStruc* Q )
Me@19 180 {
Me@19 181 void **startOfData = Q->startOfData;
Me@19 182 void **endOfData = Q->endOfData;
Me@19 183
Me@19 184 void **insertPos = Q->insertPos;
Me@19 185 void **extractPos = Q->extractPos;
Me@19 186
Me@19 187 tryAgain:
Me@19 188 //Full? (insert is just below extract when full)
Me@19 189 if( extractPos - insertPos != 1 &&
Me@19 190 !(insertPos == endOfData && extractPos == startOfData))
Me@19 191 { *(Q->insertPos) = in; //insert before move
Me@19 192 if( insertPos == endOfData ) //write new pos exactly once, correctly
Me@19 193 { Q->insertPos = startOfData;
Me@19 194 }
Me@19 195 else
Me@19 196 { Q->insertPos++;
Me@19 197 }
Me@19 198 return;
Me@19 199 }
Me@19 200 //Q is full
Me@19 201 enlargePrivQ( Q );
Me@19 202 goto tryAgain;
Me@19 203 }
Me@19 204
Me@19 205
Me@19 206 /*Returns false when the queue was full.
Me@19 207 * have option of calling make_larger_PrivQ to make more room, then try again
Me@19 208 */
seanhalle@35 209 bool32
seanhalle@35 210 writeIfSpacePrivQ( void * in, PrivQueueStruc* Q )
Me@19 211 {
Me@19 212 void **startOfData = Q->startOfData;
Me@19 213 void **endOfData = Q->endOfData;
Me@19 214
Me@19 215 void **insertPos = Q->insertPos;
Me@19 216 void **extractPos = Q->extractPos;
Me@19 217
Me@19 218 if( extractPos - insertPos != 1 &&
Me@19 219 !(insertPos == endOfData && extractPos == startOfData))
Me@19 220 { *(Q->insertPos) = in; //insert before move
Me@19 221 if( insertPos == endOfData ) //write new pos exactly once, correctly
Me@19 222 { Q->insertPos = startOfData;
Me@19 223 }
Me@19 224 else
Me@19 225 { Q->insertPos++;
Me@19 226 }
Me@19 227 return TRUE;
Me@19 228 }
Me@19 229 //Q is full
Me@19 230 return FALSE;
Me@19 231 }
seanhalle@27 232
seanhalle@32 233 int32
seanhalle@32 234 numInPrivQ( PrivQueueStruc *Q )
seanhalle@32 235 { int32 size, numIn;
seanhalle@32 236
seanhalle@32 237 if( Q->insertPos < Q->extractPos )
seanhalle@32 238 { //insert has wrapped around so numIn is:
seanhalle@32 239 // insertPos + size - extractPos -- Consider, is empty when
seanhalle@32 240 // extractPos = endOfData and insert = start -- correctly get zero
seanhalle@33 241 size = Q->endOfData - Q->startOfData + 1; //sz of 10 is 0..9
seanhalle@33 242 numIn = Q->insertPos - Q->extractPos + size - 1; //-1 bec insrt empty
seanhalle@32 243 }
seanhalle@32 244 else
seanhalle@32 245 {
seanhalle@33 246 numIn = Q->insertPos - Q->extractPos -1;//-1 bec insertPos empty
seanhalle@32 247 }
seanhalle@32 248 return numIn;
seanhalle@32 249 }
seanhalle@32 250
seanhalle@32 251
seanhalle@32 252 /*Treats queue as a stack -- no matter contents, if read done right after
seanhalle@32 253 * a push, then the pushed item is what comes out.
seanhalle@32 254 * Expands the queue size automatically when it's full.
seanhalle@32 255 */
seanhalle@32 256 void
seanhalle@32 257 pushPrivQ( void * in, PrivQueueStruc* Q )
seanhalle@32 258 {
seanhalle@32 259 while(1){
seanhalle@32 260 void **startOfData = Q->startOfData;
seanhalle@32 261 void **endOfData = Q->endOfData;
seanhalle@32 262
seanhalle@32 263 void **insertPos = Q->insertPos;
seanhalle@32 264 void **extractPos = Q->extractPos;
seanhalle@32 265
seanhalle@32 266 //Full? (insert is just below extract when full)
seanhalle@32 267 if( extractPos - insertPos != 1 &&
seanhalle@32 268 !(insertPos == endOfData && extractPos == startOfData))
seanhalle@32 269 { //insert -- but go backwards, inserting at read position then
seanhalle@32 270 // move read pos backwards
seanhalle@32 271 *(Q->extractPos) = in;
seanhalle@32 272 if( extractPos == startOfData ) //write new pos exactly once, correctly
seanhalle@32 273 { Q->extractPos = endOfData; //can't overrun then fix it 'cause
seanhalle@32 274 } // other thread might read bad pos
seanhalle@32 275 else
seanhalle@32 276 { Q->extractPos--;
seanhalle@32 277 }
seanhalle@32 278 return;
seanhalle@32 279 }
seanhalle@32 280 //Q is full
seanhalle@32 281 enlargePrivQ( Q );
seanhalle@32 282 }
seanhalle@32 283 }
seanhalle@32 284
seanhalle@32 285
seanhalle@32 286 void
seanhalle@32 287 freePrivQ( PrivQueueStruc *Q )
seanhalle@32 288 {
seanhalle@32 289 //This free is not safe to use in wrapper lib nor app code!
seanhalle@32 290 VMS_int__free( Q->startOfData );
seanhalle@32 291 VMS_int__free( Q );
seanhalle@32 292 }