Ping.
On Thu, May 17, 2012 at 11:29 AM, Doug Evans <d...@google.com> wrote: > Hi. > > This is a slightly modified version of my previous patch. > > ref: http://gcc.gnu.org/ml/gcc-patches/2012-05/msg00962.html > > The only change is to make the result of the functions an int > instead of a const pointer. > This lets them be used in places where the code is using > non-const pointers without having to apply ugly casts. > > Ok to check in? > > 2012-05-17 Doug Evans <d...@google.com> > > * leb128.h: New file. > > Index: leb128.h > =================================================================== > RCS file: leb128.h > diff -N leb128.h > --- /dev/null 1 Jan 1970 00:00:00 -0000 > +++ leb128.h 17 May 2012 18:23:29 -0000 > @@ -0,0 +1,130 @@ > +/* Utilities for reading leb128 values. > + Copyright (C) 2012 Free Software Foundation, Inc. > + > +This file is part of the libiberty library. > +Libiberty is free software; you can redistribute it and/or > +modify it under the terms of the GNU Library General Public > +License as published by the Free Software Foundation; either > +version 2 of the License, or (at your option) any later version. > + > +Libiberty 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 > +Library General Public License for more details. > + > +You should have received a copy of the GNU Library General Public > +License along with libiberty; see the file COPYING.LIB. If not, write > +to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, > +Boston, MA 02110-1301, USA. */ > + > +/* The functions defined here can be speed critical. > + Since they are all pretty small we keep things simple and just define > + them all as "static inline". */ > + > +#ifndef LEB128_H > +#define LEB128_H > + > +#include "ansidecl.h" > + > +/* Get a definition for NULL. */ > +#include <stdio.h> > + > +#ifdef HAVE_STDINT_H > +#include <stdint.h> > +#endif > +#ifdef HAVE_INTTYPES_H > +#include <inttypes.h> > +#endif > + > +/* Decode the unsigned LEB128 constant at BUF into the variable pointed to > + by R, and return the number of bytes read. > + If we read off the end of the buffer, zero is returned, > + and nothing is stored in R. > + > + Note: The result is an int instead of a pointer to the next byte to be > + read to avoid const-vs-non-const problems. */ > + > +static inline int > +read_uleb128 (const unsigned char *buf, const unsigned char *buf_end, > + uint64_t *r) > +{ > + const unsigned char *p = buf; > + unsigned int shift = 0; > + uint64_t result = 0; > + unsigned char byte; > + > + while (1) > + { > + if (p >= buf_end) > + return 0; > + > + byte = *p++; > + result |= ((uint64_t) (byte & 0x7f)) << shift; > + if ((byte & 0x80) == 0) > + break; > + shift += 7; > + } > + > + *r = result; > + return p - buf; > +} > + > +/* Decode the signed LEB128 constant at BUF into the variable pointed to > + by R, and return the number of bytes read. > + If we read off the end of the buffer, zero is returned, > + and nothing is stored in R. > + > + Note: The result is an int instead of a pointer to the next byte to be > + read to avoid const-vs-non-const problems. */ > + > +static inline int > +read_sleb128 (const unsigned char *buf, const unsigned char *buf_end, > + int64_t *r) > +{ > + const unsigned char *p = buf; > + unsigned int shift = 0; > + int64_t result = 0; > + unsigned char byte; > + > + while (1) > + { > + if (p >= buf_end) > + return 0; > + > + byte = *p++; > + result |= ((uint64_t) (byte & 0x7f)) << shift; > + shift += 7; > + if ((byte & 0x80) == 0) > + break; > + } > + if (shift < (sizeof (*r) * 8) && (byte & 0x40) != 0) > + result |= -(((uint64_t) 1) << shift); > + > + *r = result; > + return p - buf; > +} > + > +/* Return the number of bytes to read to skip past an LEB128 number in BUF. > + If the end isn't found before reaching BUF_END, return zero. > + > + Note: The result is an int instead of a pointer to the next byte to be > + read to avoid const-vs-non-const problems. */ > + > +static inline int > +skip_leb128 (const unsigned char *buf, const unsigned char *buf_end) > +{ > + const unsigned char *p = buf; > + unsigned char byte; > + > + while (1) > + { > + if (p == buf_end) > + return 0; > + > + byte = *p++; > + if ((byte & 128) == 0) > + return p - buf; > + } > +} > + > +#endif /* LEB128_H */
