release/src/router/mysql/storage/ndb/src/kernel/vm/SectionReader.cpp

   1 /* Copyright (c) 2003-2005 MySQL AB
   2
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation; version 2 of the License.
   6
   7    This program is distributed in the hope that it will be useful,
   8    but WITHOUT ANY WARRANTY; without even the implied warranty of
   9    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10    GNU General Public License for more details.
  11
  12    You should have received a copy of the GNU General Public License
  13    along with this program; if not, write to the Free Software
  14    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA */
  15
  16 #include <SectionReader.hpp>
  17 #include <TransporterDefinitions.hpp>
  18 #include "LongSignal.hpp"
  19
  20 #if 0
  21   Uint32 m_len;
  22   class SectionSegmentPool & m_pool;
  23   class SectionSegment * m_head;
  24   class SectionSegment * m_currentPos;
  25 #endif
  26
  27 SectionReader::SectionReader
  28 (struct SegmentedSectionPtr & ptr, class SectionSegmentPool & pool)
  29   : m_pool(pool)
  30 {
  31   if(ptr.p == 0){
  32     m_pos = 0;
  33     m_len = 0;
  34     m_head = 0;
  35     m_currentSegment = 0;
  36   } else {
  37     m_pos = 0;
  38     m_len = ptr.p->m_sz;
  39     m_head = ptr.p;
  40     m_currentSegment = ptr.p;
  41   }
  42 }
  43
  44 void
  45 SectionReader::reset(){
  46   m_pos = 0;
  47   m_currentSegment = m_head;
  48 }
  49
  50 bool
  51 SectionReader::step(Uint32 len){
  52   if(m_pos + len >= m_len) {
  53     m_pos++;
  54     return false;
  55   }
  56   while(len > SectionSegment::DataLength){
  57     m_currentSegment = m_pool.getPtr(m_currentSegment->m_nextSegment);
  58
  59     len -= SectionSegment::DataLength;
  60     m_pos += SectionSegment::DataLength;
  61   }
  62
  63   Uint32 ind = m_pos % SectionSegment::DataLength;
  64   while(len > 0){
  65     len--;
  66     m_pos++;
  67
  68     ind++;
  69     if(ind == SectionSegment::DataLength){
  70       ind = 0;
  71       m_currentSegment = m_pool.getPtr(m_currentSegment->m_nextSegment);
  72     }
  73   }
  74   return true;
  75 }
  76
  77 bool
  78 SectionReader::getWord(Uint32 * dst){
  79   if (peekWord(dst)) {
  80     step(1);
  81     return true;
  82   }
  83   return false;
  84 }
  85
  86 bool
  87 SectionReader::peekWord(Uint32 * dst) const {
  88   if(m_pos < m_len){
  89     Uint32 ind = m_pos % SectionSegment::DataLength;
  90     * dst = m_currentSegment->theData[ind];
  91     return true;
  92   }
  93   return false;
  94 }
  95
  96 bool
  97 SectionReader::peekWords(Uint32 * dst, Uint32 len) const {
  98   if(m_pos + len > m_len)
  99     return false;
 100
 101   Uint32 ind = (m_pos % SectionSegment::DataLength);
 102   Uint32 left = SectionSegment::DataLength - ind;
 103   SectionSegment * p = m_currentSegment;
 104
 105   while(len > left){
 106     memcpy(dst, &p->theData[ind], 4 * left);
 107     dst += left;
 108     len -= left;
 109     ind = 0;
 110     left = SectionSegment::DataLength;
 111     p = m_pool.getPtr(p->m_nextSegment);
 112   }
 113
 114   memcpy(dst, &p->theData[ind], 4 * len);
 115   return true;
 116 }
 117
 118 bool
 119 SectionReader::getWords(Uint32 * dst, Uint32 len){
 120   if(m_pos + len > m_len)
 121     return false;
 122
 123   Uint32 ind = (m_pos % SectionSegment::DataLength);
 124   Uint32 left = SectionSegment::DataLength - ind;
 125   SectionSegment * p = m_currentSegment;
 126
 127   while(len > left){
 128     memcpy(dst, &p->theData[ind], 4 * left);
 129     dst += left;
 130     len -= left;
 131     ind = 0;
 132     left = SectionSegment::DataLength;
 133     p = m_pool.getPtr(p->m_nextSegment);
 134   }
 135
 136   memcpy(dst, &p->theData[ind], 4 * len);
 137
 138   m_pos += len;
 139   m_currentSegment = p;
 140   return true;
 141 }
 142