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annotate PrivateQueue.c @ 44:67c7f5a0308b

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Renamed VMS to PR, in new branch
author Sean Halle <seanhalle@yahoo.com>
date Fri, 08 Mar 2013 05:40:08 -0800
parents d01d48b023ca
children 1ea30ca7093c
rev   line source
Me@19 1 /*
seanhalle@44 2 * Copyright 2009 OpenSourceResearchInstitute.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@43 30 retQ = (PrivQueueStruc *) PR_int__malloc( sizeof( PrivQueueStruc ) );
Me@19 31
seanhalle@32 32 //This malloc is not safe to use in wrapper lib nor app code!
seanhalle@43 33 retQ->startOfData = PR_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
seanhalle@44 43 /*A bit tricky, 'cause have to copy in two halves, and be careful about case
seanhalle@44 44 * when insert is at top and extract at bottom..
seanhalle@44 45 */
Me@19 46 void
Me@19 47 enlargePrivQ( PrivQueueStruc *Q )
seanhalle@35 48 { int32 oldSize, newSize, topPartSize, bottPartSize;
seanhalle@32 49 int8 *insertPos, *extractPos;
seanhalle@32 50 int8 *oldStartOfData, *oldEndOfData, *newStartOfData, *newEndOfData;
seanhalle@35 51 int32 insertOffsetBytes, extractOffsetBytes;
seanhalle@35 52 int8 *copyStartAddr;
Me@19 53
seanhalle@32 54 oldStartOfData = (int8 *)Q->startOfData;
seanhalle@32 55 oldEndOfData = (int8 *)Q->endOfData;
seanhalle@32 56 insertPos = (int8 *)Q->insertPos;
seanhalle@32 57 extractPos = (int8 *)Q->extractPos;
Me@19 58
seanhalle@32 59 //TODO: verify these get number of bytes correct
seanhalle@35 60 insertOffsetBytes = (int32)(insertPos - oldStartOfData);
seanhalle@35 61 extractOffsetBytes = (int32)(extractPos - oldStartOfData);
seanhalle@32 62
seanhalle@35 63 oldSize = oldEndOfData - oldStartOfData + 1; //in bytes
seanhalle@32 64 newSize = 2 * oldSize;
seanhalle@32 65
seanhalle@32 66 //This malloc is not safe to use in wrapper lib nor app code!
seanhalle@43 67 Q->startOfData = (void **)PR_int__malloc( newSize );
seanhalle@32 68 newStartOfData = (int8 *)Q->startOfData;
seanhalle@32 69 newEndOfData = newStartOfData + newSize; //all calcs in Bytes
seanhalle@32 70 Q->endOfData = (void **)newEndOfData;
seanhalle@32 71
seanhalle@32 72 //TODO: test all of this, for both cases
seanhalle@32 73
seanhalle@32 74 //Moving the data and pointers to the new array is
seanhalle@32 75 //a little trickier than at first it seems.. the top part
seanhalle@32 76 // of old queue must be moved to the top part of new queue, while
seanhalle@32 77 // bottom part of old to bottom part of new, then the new insert
seanhalle@32 78 // and extract positions calculated by offset from top and bottom
seanhalle@32 79 //UNLESS the one case where old extract was at bottom and insert
seanhalle@32 80 // was at top.
seanhalle@32 81 //TODO: check that this is correct!
seanhalle@35 82 if( extractPos == oldStartOfData && insertPos == oldEndOfData )
seanhalle@32 83 {
seanhalle@32 84 memcpy( newStartOfData, oldStartOfData, oldSize ); //oldSize is bytes
seanhalle@32 85 Q->extractPos = Q->startOfData; //start of valid data
seanhalle@32 86 Q->insertPos = Q->startOfData + oldSize - 1; //end of valid data
seanhalle@32 87 }
seanhalle@32 88 else //have to copy two parts separately, then calc positions
seanhalle@32 89 { //TODO: check end-addr, sizes, and new positions carefully
seanhalle@35 90
seanhalle@32 91 //copy top part, starting at extract up until end of data,
seanhalle@35 92 // into top of new array
seanhalle@32 93 topPartSize = oldEndOfData - extractPos + 1; //+1 includes extractPos
seanhalle@35 94 copyStartAddr = newEndOfData - topPartSize + 1;//+1 cancels other
seanhalle@32 95 memcpy( copyStartAddr, Q->extractPos, topPartSize );
seanhalle@35 96 Q->extractPos = (void **)copyStartAddr; //extract just-copied data
seanhalle@35 97
seanhalle@32 98 //copy bottom part, from old start up to old insert,
seanhalle@35 99 // into bottom of new array
seanhalle@32 100 bottPartSize = oldSize - topPartSize - 1; //-1 for empty insertPos
seanhalle@32 101 memcpy( newStartOfData, oldStartOfData, bottPartSize );
seanhalle@32 102 Q->insertPos = (void **)(newStartOfData + bottPartSize);
seanhalle@32 103 }
seanhalle@32 104 //This free is not safe to use in wrapper lib nor app code!
seanhalle@43 105 PR_int__free(oldStartOfData);
Me@19 106 }
Me@19 107
Me@19 108
seanhalle@37 109 /*Returns TRUE when queue is empty
seanhalle@37 110 */
seanhalle@37 111 bool32 isEmptyPrivQ( PrivQueueStruc* Q )
seanhalle@37 112 { void *out = 0;
seanhalle@37 113 void **startOfData = Q->startOfData;
seanhalle@37 114 void **endOfData = Q->endOfData;
seanhalle@37 115
seanhalle@37 116 void **insertPos = Q->insertPos;
seanhalle@37 117 void **extractPos = Q->extractPos;
seanhalle@37 118
seanhalle@37 119 //if not empty -- (extract is just below insert when empty)
seanhalle@37 120 if( insertPos - extractPos != 1 &&
seanhalle@37 121 !(extractPos == endOfData && insertPos == startOfData))
seanhalle@37 122 {
seanhalle@37 123 return FALSE;
seanhalle@37 124 }
seanhalle@37 125 //Q is empty
seanhalle@37 126 return TRUE;
seanhalle@37 127 }
seanhalle@37 128
seanhalle@37 129 /*Returns NULL when queue is empty
seanhalle@37 130 */
seanhalle@37 131 void* peekPrivQ( PrivQueueStruc* Q )
seanhalle@37 132 { void *out = 0;
seanhalle@37 133 void **startOfData = Q->startOfData;
seanhalle@37 134 void **endOfData = Q->endOfData;
seanhalle@37 135
seanhalle@37 136 void **insertPos = Q->insertPos;
seanhalle@37 137 void **extractPos = Q->extractPos;
seanhalle@37 138
seanhalle@37 139 //if not empty -- (extract is just below insert when empty)
seanhalle@37 140 if( insertPos - extractPos != 1 &&
seanhalle@37 141 !(extractPos == endOfData && insertPos == startOfData))
seanhalle@37 142 {
seanhalle@37 143 out = *(Q->extractPos);
seanhalle@37 144 return out;
seanhalle@37 145 }
seanhalle@37 146 //Q is empty
seanhalle@37 147 return NULL;
seanhalle@37 148 }
seanhalle@37 149
seanhalle@37 150
Me@19 151 /*Returns NULL when queue is empty
Me@19 152 */
Me@19 153 void* readPrivQ( PrivQueueStruc* Q )
Me@19 154 { void *out = 0;
Me@19 155 void **startOfData = Q->startOfData;
Me@19 156 void **endOfData = Q->endOfData;
Me@19 157
Me@19 158 void **insertPos = Q->insertPos;
Me@19 159 void **extractPos = Q->extractPos;
Me@19 160
Me@19 161 //if not empty -- (extract is just below insert when empty)
Me@19 162 if( insertPos - extractPos != 1 &&
Me@19 163 !(extractPos == endOfData && insertPos == startOfData))
Me@19 164 { //move before read
Me@19 165 if( extractPos == endOfData ) //write new pos exactly once, correctly
Me@19 166 { Q->extractPos = startOfData; //can't overrun then fix it 'cause
Me@19 167 } // other thread might read bad pos
Me@19 168 else
Me@19 169 { Q->extractPos++;
Me@19 170 }
Me@19 171 out = *(Q->extractPos);
Me@19 172 return out;
Me@19 173 }
Me@19 174 //Q is empty
Me@19 175 return NULL;
Me@19 176 }
Me@19 177
Me@19 178
Me@19 179 /*Expands the queue size automatically when it's full
Me@19 180 */
Me@19 181 void
Me@19 182 writePrivQ( void * in, PrivQueueStruc* Q )
Me@19 183 {
Me@19 184 void **startOfData = Q->startOfData;
Me@19 185 void **endOfData = Q->endOfData;
Me@19 186
Me@19 187 void **insertPos = Q->insertPos;
Me@19 188 void **extractPos = Q->extractPos;
Me@19 189
Me@19 190 tryAgain:
Me@19 191 //Full? (insert is just below extract when full)
Me@19 192 if( extractPos - insertPos != 1 &&
Me@19 193 !(insertPos == endOfData && extractPos == startOfData))
Me@19 194 { *(Q->insertPos) = in; //insert before move
Me@19 195 if( insertPos == endOfData ) //write new pos exactly once, correctly
Me@19 196 { Q->insertPos = startOfData;
Me@19 197 }
Me@19 198 else
Me@19 199 { Q->insertPos++;
Me@19 200 }
Me@19 201 return;
Me@19 202 }
Me@19 203 //Q is full
Me@19 204 enlargePrivQ( Q );
Me@19 205 goto tryAgain;
Me@19 206 }
Me@19 207
Me@19 208
Me@19 209 /*Returns false when the queue was full.
Me@19 210 * have option of calling make_larger_PrivQ to make more room, then try again
Me@19 211 */
seanhalle@35 212 bool32
seanhalle@35 213 writeIfSpacePrivQ( void * in, PrivQueueStruc* Q )
Me@19 214 {
Me@19 215 void **startOfData = Q->startOfData;
Me@19 216 void **endOfData = Q->endOfData;
Me@19 217
Me@19 218 void **insertPos = Q->insertPos;
Me@19 219 void **extractPos = Q->extractPos;
Me@19 220
Me@19 221 if( extractPos - insertPos != 1 &&
Me@19 222 !(insertPos == endOfData && extractPos == startOfData))
Me@19 223 { *(Q->insertPos) = in; //insert before move
Me@19 224 if( insertPos == endOfData ) //write new pos exactly once, correctly
Me@19 225 { Q->insertPos = startOfData;
Me@19 226 }
Me@19 227 else
Me@19 228 { Q->insertPos++;
Me@19 229 }
Me@19 230 return TRUE;
Me@19 231 }
Me@19 232 //Q is full
Me@19 233 return FALSE;
Me@19 234 }
seanhalle@27 235
seanhalle@32 236 int32
seanhalle@32 237 numInPrivQ( PrivQueueStruc *Q )
seanhalle@32 238 { int32 size, numIn;
seanhalle@32 239
seanhalle@32 240 if( Q->insertPos < Q->extractPos )
seanhalle@32 241 { //insert has wrapped around so numIn is:
seanhalle@32 242 // insertPos + size - extractPos -- Consider, is empty when
seanhalle@32 243 // extractPos = endOfData and insert = start -- correctly get zero
seanhalle@33 244 size = Q->endOfData - Q->startOfData + 1; //sz of 10 is 0..9
seanhalle@33 245 numIn = Q->insertPos - Q->extractPos + size - 1; //-1 bec insrt empty
seanhalle@32 246 }
seanhalle@32 247 else
seanhalle@32 248 {
seanhalle@33 249 numIn = Q->insertPos - Q->extractPos -1;//-1 bec insertPos empty
seanhalle@32 250 }
seanhalle@32 251 return numIn;
seanhalle@32 252 }
seanhalle@32 253
seanhalle@32 254
seanhalle@32 255 /*Treats queue as a stack -- no matter contents, if read done right after
seanhalle@32 256 * a push, then the pushed item is what comes out.
seanhalle@32 257 * Expands the queue size automatically when it's full.
seanhalle@32 258 */
seanhalle@32 259 void
seanhalle@32 260 pushPrivQ( void * in, PrivQueueStruc* Q )
seanhalle@32 261 {
seanhalle@32 262 while(1){
seanhalle@32 263 void **startOfData = Q->startOfData;
seanhalle@32 264 void **endOfData = Q->endOfData;
seanhalle@32 265
seanhalle@32 266 void **insertPos = Q->insertPos;
seanhalle@32 267 void **extractPos = Q->extractPos;
seanhalle@32 268
seanhalle@32 269 //Full? (insert is just below extract when full)
seanhalle@32 270 if( extractPos - insertPos != 1 &&
seanhalle@32 271 !(insertPos == endOfData && extractPos == startOfData))
seanhalle@32 272 { //insert -- but go backwards, inserting at read position then
seanhalle@32 273 // move read pos backwards
seanhalle@32 274 *(Q->extractPos) = in;
seanhalle@32 275 if( extractPos == startOfData ) //write new pos exactly once, correctly
seanhalle@32 276 { Q->extractPos = endOfData; //can't overrun then fix it 'cause
seanhalle@32 277 } // other thread might read bad pos
seanhalle@32 278 else
seanhalle@32 279 { Q->extractPos--;
seanhalle@32 280 }
seanhalle@32 281 return;
seanhalle@32 282 }
seanhalle@32 283 //Q is full
seanhalle@32 284 enlargePrivQ( Q );
seanhalle@32 285 }
seanhalle@32 286 }
seanhalle@32 287
seanhalle@32 288
seanhalle@44 289 /*NOTE: This free is not safe to use in wrapper lib nor app code
seanhalle@44 290 */
seanhalle@44 291 void
seanhalle@44 292 freePrivQ( PrivQueueStruc *Q )
seanhalle@44 293 {
seanhalle@44 294 //This free is not safe to use in wrapper lib nor app code!
seanhalle@44 295 PR_int__free( Q->startOfData );
seanhalle@44 296 PR_int__free( Q );
seanhalle@44 297 }