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      1 /* Find CU for given offset.
      2    Copyright (C) 2003, 2004 Red Hat, Inc.
      3    Written by Ulrich Drepper <drepper (at) redhat.com>, 2003.
      4 
      5    This program is Open Source software; you can redistribute it and/or
      6    modify it under the terms of the Open Software License version 1.0 as
      7    published by the Open Source Initiative.
      8 
      9    You should have received a copy of the Open Software License along
     10    with this program; if not, you may obtain a copy of the Open Software
     11    License version 1.0 from http://www.opensource.org/licenses/osl.php or
     12    by writing the Open Source Initiative c/o Lawrence Rosen, Esq.,
     13    3001 King Ranch Road, Ukiah, CA 95482.   */
     14 
     15 #ifdef HAVE_CONFIG_H
     16 # include <config.h>
     17 #endif
     18 
     19 #include <assert.h>
     20 #include <search.h>
     21 #include "libdwP.h"
     22 
     23 
     24 static int
     25 findcu_cb (const void *arg1, const void *arg2)
     26 {
     27   struct Dwarf_CU *cu1 = (struct Dwarf_CU *) arg1;
     28   struct Dwarf_CU *cu2 = (struct Dwarf_CU *) arg2;
     29 
     30   /* Find out which of the two arguments is the search value.  It has
     31      end offset 0.  */
     32   if (cu1->end == 0)
     33     {
     34       if (cu1->start < cu2->start)
     35 	return -1;
     36       if (cu1->start >= cu2->end)
     37 	return 1;
     38     }
     39   else
     40     {
     41       if (cu2->start < cu1->start)
     42 	return 1;
     43       if (cu2->start >= cu1->end)
     44 	return -1;
     45     }
     46 
     47   return 0;
     48 }
     49 
     50 
     51 struct Dwarf_CU *
     52 __libdw_findcu (dbg, start)
     53      Dwarf *dbg;
     54      Dwarf_Off start;
     55 {
     56   /* Maybe we already know that CU.  */
     57   struct Dwarf_CU fake = { .start = start, .end = 0 };
     58   struct Dwarf_CU **found = tfind (&fake, &dbg->cu_tree, findcu_cb);
     59   if (found != NULL)
     60     return *found;
     61 
     62   if (start < dbg->next_cu_offset)
     63     {
     64       __libdw_seterrno (DWARF_E_INVALID_DWARF);
     65       return NULL;
     66     }
     67 
     68   /* No.  Then read more CUs.  */
     69   while (1)
     70     {
     71       Dwarf_Off oldoff = dbg->next_cu_offset;
     72       uint8_t address_size;
     73       uint8_t offset_size;
     74       Dwarf_Off abbrev_offset;
     75 
     76       if (dwarf_nextcu (dbg, oldoff, &dbg->next_cu_offset, NULL,
     77 			&abbrev_offset, &address_size, &offset_size) != 0)
     78 	/* No more entries.  */
     79 	return NULL;
     80 
     81       /* Create an entry for this CU.  */
     82       struct Dwarf_CU *newp = libdw_typed_alloc (dbg, struct Dwarf_CU);
     83 
     84       newp->dbg = dbg;
     85       newp->start = oldoff;
     86       newp->end = dbg->next_cu_offset;
     87       newp->address_size = address_size;
     88       newp->offset_size = offset_size;
     89       Dwarf_Abbrev_Hash_init (&newp->abbrev_hash, 41);
     90       newp->orig_abbrev_offset = newp->last_abbrev_offset = abbrev_offset;
     91       newp->lines = NULL;
     92       newp->locs = NULL;
     93 
     94       /* Add the new entry to the search tree.  */
     95       if (tsearch (newp, &dbg->cu_tree, findcu_cb) == NULL)
     96 	{
     97 	  /* Something went wrong.  Unfo the operation.  */
     98 	  dbg->next_cu_offset = oldoff;
     99 	  __libdw_seterrno (DWARF_E_NOMEM);
    100 	  return NULL;
    101 	}
    102 
    103       /* Is this the one we are looking for?  */
    104       if (start < dbg->next_cu_offset)
    105 	// XXX Match exact offset.
    106 	return newp;
    107     }
    108   /* NOTREACHED */
    109 }
    110