src/LEB128.cpp

   1
   2
   3 // Decode an unsigned LEB128
   4 // Algorithm from Appendix C of the DWARF 2, and 3, spec section "7.6"
   5 unsigned long ReadULEB128(char *addr)
   6 {
   7         unsigned long result = 0;
   8         size_t shift = 0;
   9         unsigned char byte;
  10
  11         do
  12         {
  13                 byte = *addr++;
  14                 result |= (byte & 0x7f) << shift;
  15                 shift += 7;
  16         }
  17         while ((byte & 0x80));
  18
  19         return result;
  20 }
  21
  22
  23 // Decode a signed LEB128
  24 // Algorithm from Appendix C of the DWARF 2, and 3, spec section "7.6"
  25 long ReadLEB128(char *addr)
  26 {
  27         long result = 0;
  28         size_t shift = 0;
  29         unsigned char byte;
  30
  31         do
  32         {
  33                 byte = *addr++;
  34                 result |= (byte & 0x7f) << shift;
  35                 shift += 7;
  36         }
  37         while ((byte & 0x80));
  38
  39         if ((shift < (8 * sizeof(result))) && (byte & 0x40))
  40         {
  41                 result |= (~0 << shift);
  42         }
  43
  44         return result;
  45 }
  46