1 files changed, 146 insertions, 0 deletions
diff --git a/libdwarf/dwarf_leb.c b/libdwarf/dwarf_leb.c
new file mode 100644
index 0000000..7e01d84
--- /dev/null
+++ b/libdwarf/dwarf_leb.c
@@ -0,0 +1,146 @@
+/*
+
+  Copyright (C) 2000,2004 Silicon Graphics, Inc.  All Rights Reserved.
+  Portions Copyright 2011 David Anderson. All Rights Reserved.
+
+  This program is free software; you can redistribute it and/or modify it
+  under the terms of version 2.1 of the GNU Lesser General Public License 
+  as published by the Free Software Foundation.
+
+  This program is distributed in the hope that it would be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
+
+  Further, this software is distributed without any warranty that it is
+  free of the rightful claim of any third person regarding infringement 
+  or the like.  Any license provided herein, whether implied or 
+  otherwise, applies only to this software file.  Patent licenses, if
+  any, provided herein do not apply to combinations of this program with 
+  other software, or any other product whatsoever.  
+
+  You should have received a copy of the GNU Lesser General Public 
+  License along with this program; if not, write the Free Software 
+  Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston MA 02110-1301,
+  USA.
+
+  Contact information:  Silicon Graphics, Inc., 1500 Crittenden Lane,
+  Mountain View, CA 94043, or:
+
+  http://www.sgi.com
+
+  For further information regarding this notice, see:
+
+  http://oss.sgi.com/projects/GenInfo/NoticeExplan
+
+*/
+
+
+
+#include "config.h"
+#include "dwarf_incl.h"
+#include <stdio.h>
+
+
+/* Decode ULEB */
+Dwarf_Unsigned
+_dwarf_decode_u_leb128(Dwarf_Small * leb128, Dwarf_Word * leb128_length)
+{
+    unsigned char byte;
+    Dwarf_Word word_number;
+    Dwarf_Unsigned number;
+    Dwarf_Sword shift;
+    Dwarf_Sword byte_length;
+
+    /*  The following unrolls-the-loop for the first few bytes and
+        unpacks into 32 bits to make this as fast as possible.
+        word_number is assumed big enough that the shift has a defined
+        result. */
+    if ((*leb128 & 0x80) == 0) {
+        if (leb128_length != NULL)
+            *leb128_length = 1;
+        return (*leb128);
+    } else if ((*(leb128 + 1) & 0x80) == 0) {
+        if (leb128_length != NULL)
+            *leb128_length = 2;
+
+        word_number = *leb128 & 0x7f;
+        word_number |= (*(leb128 + 1) & 0x7f) << 7;
+        return (word_number);
+    } else if ((*(leb128 + 2) & 0x80) == 0) {
+        if (leb128_length != NULL)
+            *leb128_length = 3;
+
+        word_number = *leb128 & 0x7f;
+        word_number |= (*(leb128 + 1) & 0x7f) << 7;
+        word_number |= (*(leb128 + 2) & 0x7f) << 14;
+        return (word_number);
+    } else if ((*(leb128 + 3) & 0x80) == 0) {
+        if (leb128_length != NULL)
+            *leb128_length = 4;
+
+        word_number = *leb128 & 0x7f;
+        word_number |= (*(leb128 + 1) & 0x7f) << 7;
+        word_number |= (*(leb128 + 2) & 0x7f) << 14;
+        word_number |= (*(leb128 + 3) & 0x7f) << 21;
+        return (word_number);
+    }
+
+    /*  The rest handles long numbers Because the 'number' may be larger 
+        than the default int/unsigned, we must cast the 'byte' before
+        the shift for the shift to have a defined result. */
+    number = 0;
+    shift = 0;
+    byte_length = 1;
+    byte = *(leb128);
+    for (;;) {
+        number |= ((Dwarf_Unsigned) (byte & 0x7f)) << shift;
+
+        if ((byte & 0x80) == 0) {
+            if (leb128_length != NULL)
+                *leb128_length = byte_length;
+            return (number);
+        }
+        shift += 7;
+
+        byte_length++;
+        ++leb128;
+        byte = *leb128;
+    }
+}
+
+#define BITSINBYTE 8
+
+/*  decode SLEB */
+Dwarf_Signed
+_dwarf_decode_s_leb128(Dwarf_Small * leb128, Dwarf_Word * leb128_length)
+{
+    Dwarf_Signed number = 0;
+    Dwarf_Bool sign = 0;
+    Dwarf_Sword shift = 0;
+    unsigned char byte = *leb128;
+    Dwarf_Sword byte_length = 1;
+
+    /*  byte_length being the number of bytes of data absorbed so far in 
+        turning the leb into a Dwarf_Signed. */
+
+    for (;;) {
+        sign = byte & 0x40;
+        number |= ((Dwarf_Signed) ((byte & 0x7f))) << shift;
+        shift += 7;
+
+        if ((byte & 0x80) == 0) {
+            break;
+        }
+        ++leb128;
+        byte = *leb128;
+        byte_length++;
+    }
+
+    if ((shift < sizeof(Dwarf_Signed) * BITSINBYTE) && sign) {
+        number |= -((Dwarf_Signed) 1 << shift);
+    }
+
+    if (leb128_length != NULL)
+        *leb128_length = byte_length;
+    return (number);
+}