add ostep homeworks
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yuchen
238
related_info/ostep/ostep3-malloc.py
Executable file
238
related_info/ostep/ostep3-malloc.py
Executable file
@@ -0,0 +1,238 @@
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#! /usr/bin/env python
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import random
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from optparse import OptionParser
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class malloc:
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def __init__(self, size, start, headerSize, policy, order, coalesce, align):
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# size of space
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self.size = size
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# info about pretend headers
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self.headerSize = headerSize
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# init free list
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self.freelist = []
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self.freelist.append((start, size))
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# keep track of ptr to size mappings
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self.sizemap = {}
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# policy
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self.policy = policy
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assert(self.policy in ['FIRST', 'BEST', 'WORST'])
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# list ordering
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self.returnPolicy = order
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assert(self.returnPolicy in ['ADDRSORT', 'SIZESORT+', 'SIZESORT-', 'INSERT-FRONT', 'INSERT-BACK'])
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# this does a ridiculous full-list coalesce, but that is ok
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self.coalesce = coalesce
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# alignment (-1 if no alignment)
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self.align = align
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assert(self.align == -1 or self.align > 0)
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def addToMap(self, addr, size):
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assert(addr not in self.sizemap)
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self.sizemap[addr] = size
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# print 'adding', addr, 'to map of size', size
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def malloc(self, size):
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if self.align != -1:
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left = size % self.align
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if left != 0:
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diff = self.align - left
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else:
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diff = 0
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# print 'aligning: adding %d to %d' % (diff, size)
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size += diff
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size += self.headerSize
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bestIdx = -1
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if self.policy == 'BEST':
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bestSize = self.size + 1
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elif self.policy == 'WORST' or self.policy == 'FIRST':
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bestSize = -1
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count = 0
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for i in range(len(self.freelist)):
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eaddr, esize = self.freelist[i][0], self.freelist[i][1]
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count += 1
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if esize >= size and ((self.policy == 'BEST' and esize < bestSize) or
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(self.policy == 'WORST' and esize > bestSize) or
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(self.policy == 'FIRST')):
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bestAddr = eaddr
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bestSize = esize
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bestIdx = i
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if self.policy == 'FIRST':
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break
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if bestIdx != -1:
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if bestSize > size:
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# print 'SPLIT', bestAddr, size
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self.freelist[bestIdx] = (bestAddr + size, bestSize - size)
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self.addToMap(bestAddr, size)
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elif bestSize == size:
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# print 'PERFECT MATCH (no split)', bestAddr, size
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self.freelist.pop(bestIdx)
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self.addToMap(bestAddr, size)
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else:
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abort('should never get here')
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return (bestAddr, count)
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# print '*** FAILED TO FIND A SPOT', size
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return (-1, count)
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def free(self, addr):
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# simple back on end of list, no coalesce
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if addr not in self.sizemap:
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return -1
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size = self.sizemap[addr]
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if self.returnPolicy == 'INSERT-BACK':
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self.freelist.append((addr, size))
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elif self.returnPolicy == 'INSERT-FRONT':
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self.freelist.insert(0, (addr, size))
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elif self.returnPolicy == 'ADDRSORT':
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self.freelist.append((addr, size))
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self.freelist = sorted(self.freelist, key=lambda e: e[0])
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elif self.returnPolicy == 'SIZESORT+':
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self.freelist.append((addr, size))
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self.freelist = sorted(self.freelist, key=lambda e: e[1], reverse=False)
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elif self.returnPolicy == 'SIZESORT-':
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self.freelist.append((addr, size))
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self.freelist = sorted(self.freelist, key=lambda e: e[1], reverse=True)
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# not meant to be an efficient or realistic coalescing...
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if self.coalesce == True:
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self.newlist = []
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self.curr = self.freelist[0]
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for i in range(1, len(self.freelist)):
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eaddr, esize = self.freelist[i]
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if eaddr == (self.curr[0] + self.curr[1]):
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self.curr = (self.curr[0], self.curr[1] + esize)
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else:
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self.newlist.append(self.curr)
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self.curr = eaddr, esize
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self.newlist.append(self.curr)
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self.freelist = self.newlist
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del self.sizemap[addr]
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return 0
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def dump(self):
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print 'Free List [ Size %d ]: ' % len(self.freelist),
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for e in self.freelist:
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print '[ addr:%d sz:%d ]' % (e[0], e[1]),
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print ''
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#
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# main program
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#
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parser = OptionParser()
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parser.add_option('-s', '--seed', default=0, help='the random seed', action='store', type='int', dest='seed')
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parser.add_option('-S', '--size', default=100, help='size of the heap', action='store', type='int', dest='heapSize')
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parser.add_option('-b', '--baseAddr', default=1000, help='base address of heap', action='store', type='int', dest='baseAddr')
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parser.add_option('-H', '--headerSize', default=0, help='size of the header', action='store', type='int', dest='headerSize')
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parser.add_option('-a', '--alignment', default=-1, help='align allocated units to size; -1->no align', action='store', type='int', dest='alignment')
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parser.add_option('-p', '--policy', default='BEST', help='list search (BEST, WORST, FIRST)', action='store', type='string', dest='policy')
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parser.add_option('-l', '--listOrder', default='ADDRSORT', help='list order (ADDRSORT, SIZESORT+, SIZESORT-, INSERT-FRONT, INSERT-BACK)', action='store', type='string', dest='order')
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parser.add_option('-C', '--coalesce', default=False, help='coalesce the free list?', action='store_true', dest='coalesce')
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parser.add_option('-n', '--numOps', default=10, help='number of random ops to generate', action='store', type='int', dest='opsNum')
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parser.add_option('-r', '--range', default=10, help='max alloc size', action='store', type='int', dest='opsRange')
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parser.add_option('-P', '--percentAlloc',default=50, help='percent of ops that are allocs', action='store', type='int', dest='opsPAlloc')
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parser.add_option('-A', '--allocList', default='', help='instead of random, list of ops (+10,-0,etc)', action='store', type='string', dest='opsList')
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parser.add_option('-c', '--compute', default=False, help='compute answers for me', action='store_true', dest='solve')
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(options, args) = parser.parse_args()
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m = malloc(int(options.heapSize), int(options.baseAddr), int(options.headerSize),
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options.policy, options.order, options.coalesce, options.alignment)
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percent = int(options.opsPAlloc) / 100.0
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random.seed(int(options.seed))
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p = {}
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L = []
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assert(percent > 0)
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if options.opsList == '':
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c = 0
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j = 0
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while j < int(options.opsNum):
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pr = False
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if random.random() < percent:
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size = int(random.random() * int(options.opsRange)) + 1
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ptr, cnt = m.malloc(size)
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if ptr != -1:
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p[c] = ptr
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L.append(c)
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print 'ptr[%d] = Alloc(%d)' % (c, size),
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if options.solve == True:
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print ' returned %d (searched %d elements)' % (ptr + options.headerSize, cnt)
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else:
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print ' returned ?'
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c += 1
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j += 1
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pr = True
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else:
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if len(p) > 0:
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# pick random one to delete
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d = int(random.random() * len(L))
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rc = m.free(p[L[d]])
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print 'Free(ptr[%d])' % L[d],
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if options.solve == True:
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print 'returned %d' % rc
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else:
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print 'returned ?'
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del p[L[d]]
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del L[d]
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# print 'DEBUG p', p
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# print 'DEBUG L', L
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pr = True
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j += 1
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if pr:
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if options.solve == True:
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m.dump()
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else:
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print 'List? '
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print ''
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else:
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c = 0
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for op in options.opsList.split(','):
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if op[0] == '+':
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# allocation!
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size = int(op.split('+')[1])
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ptr, cnt = m.malloc(size)
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if ptr != -1:
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p[c] = ptr
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print 'ptr[%d] = Alloc(%d)' % (c, size),
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if options.solve == True:
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print ' returned %d (searched %d elements)' % (ptr, cnt)
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else:
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print ' returned ?'
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c += 1
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elif op[0] == '-':
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# free
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index = int(op.split('-')[1])
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if index >= len(p):
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print 'Invalid Free: Skipping'
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continue
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print 'Free(ptr[%d])' % index,
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rc = m.free(p[index])
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if options.solve == True:
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print 'returned %d' % rc
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else:
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print 'returned ?'
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else:
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abort('badly specified operand: must be +Size or -Index')
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if options.solve == True:
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m.dump()
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else:
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print 'List?'
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print ''
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