/* OpenIDA - Outil d'analyse de fichiers binaires
 * utils.h - prototypes pour les fonctions d'aisance vis à vis du format DWARF
 *
 * Copyright (C) 2008 Cyrille Bagard
 *
 *  This file is part of OpenIDA.
 *
 *  OpenIDA is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  OpenIDA is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Foobar.  If not, see <http://www.gnu.org/licenses/>.
 */


#include "utils.h"


#include "dwarf-int.h"



/******************************************************************************
*                                                                             *
*  Paramètres  : format = informations de débogage à consulter.               *
*                pos    = tête de lecture à mettre à jour. [OUT]              *
*                value  = valeur au format LEB128 lue. [OUT]                  *
*                                                                             *
*  Description : Lit une valeur Little Endian Base 128 signée.                *
*                                                                             *
*  Retour      : Bilan de l'opération.                                        *
*                                                                             *
*  Remarques   : -                                                            *
*                                                                             *
******************************************************************************/

bool read_leb128(dwarf_format *format, off_t *pos, int64_t *value)
{
    int shift;                              /* Décallage à appliquer       */
    off_t i;                                /* Boucle de parcours          */

    *value = 0;

    for (i = 0; i < 8; i++)
    {
        /* On évite les débordements... */
        if ((*pos + i) >= DBG_FORMAT(format)->length) return false;

        *value |= (DBG_FORMAT(format)->content[*pos + i] & 0x7f) << shift;

        shift += 7;
        (*pos)++;

        if ((DBG_FORMAT(format)->content[*pos] & 0x80) == 0x00) break;

    }

    if ((shift < 64) && (DBG_FORMAT(format)->content[*pos - 1] & 0x40) == 0x40)
        *value |= - (1 << shift);

    return (i < 8);

}