Add crc32 function to libiberty

[Ian Lance Taylor <iant at google dot com>]

Some upcoming work in gold (by Sriraman Tallam) requires a CRC function.
I could add a CRC function to gold, but I think it makes sense to add it
to libiberty instead.  This CRC function is a copy of the one in gdb,
except that the table of constants is precomputed.  The gdb maintainers
may want to consider switching to this version--I don't think 1K of
read-only data space is all that much these days.

I am running a bootstrap on x86_64-unknown-linux-gnu and plan to commit
this shortly.

Ian


include/ChangeLog:

2009-07-24  Ian Lance Taylor  <iant@google.com>

	* libiberty.h (crc32): Declare.

libiberty/ChangeLog:

2009-07-24  Ian Lance Taylor  <iant@google.com>

	* crc32.c: New file.
	* Makefile.in: Rebuild dependencies.
	(CFILES): Add crc32.c.
	(REQUIRED_OFILES): Add ./crc32.o.
	* functions.texi: Rebuild.


Index: include/libiberty.h
===================================================================
--- include/libiberty.h	(revision 150064)
+++ include/libiberty.h	(working copy)
@@ -1,6 +1,7 @@
 /* Function declarations for libiberty.
 
-   Copyright 2001, 2002, 2005, 2007 Free Software Foundation, Inc.
+   Copyright 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
+   2006, 2007, 2008, 2009 Free Software Foundation, Inc.
    
    Note - certain prototypes declared in this header file are for
    functions whoes implementation copyright does not belong to the
@@ -311,6 +312,8 @@ extern void *xmemdup (const void *, size
 extern double physmem_total (void);
 extern double physmem_available (void);
 
+/* Compute the 32-bit CRC of a block of memory.  */
+extern unsigned int crc32 (const unsigned char *, int, unsigned int);
 
 /* These macros provide a K&R/C89/C++-friendly way of allocating structures
    with nice encapsulation.  The XDELETE*() macros are technically
Index: libiberty/Makefile.in
===================================================================
--- libiberty/Makefile.in	(revision 150064)
+++ libiberty/Makefile.in	(working copy)
@@ -124,7 +124,7 @@ COMPILE.c = $(CC) -c @DEFS@ $(CFLAGS) $(
 CFILES = alloca.c argv.c asprintf.c atexit.c				\
 	basename.c bcmp.c bcopy.c bsearch.c bzero.c			\
 	calloc.c choose-temp.c clock.c concat.c cp-demangle.c		\
-	 cp-demint.c cplus-dem.c					\
+	 cp-demint.c cplus-dem.c crc32.c				\
 	dyn-string.c							\
 	fdmatch.c ffs.c fibheap.c filename_cmp.c floatformat.c		\
 	fnmatch.c fopen_unlocked.c					\
@@ -160,7 +160,7 @@ CFILES = alloca.c argv.c asprintf.c atex
 REQUIRED_OFILES =							\
 	./regex.o ./cplus-dem.o ./cp-demangle.o ./md5.o ./sha1.o	\
 	./alloca.o ./argv.o						\
-	./choose-temp.o ./concat.o ./cp-demint.o			\
+	./choose-temp.o ./concat.o ./cp-demint.o ./crc32.o		\
 	./dyn-string.o							\
 	./fdmatch.o ./fibheap.o ./filename_cmp.o ./floatformat.o	\
 	./fnmatch.o ./fopen_unlocked.o					\
@@ -603,6 +603,12 @@ $(CONFIGURED_OFILES): stamp-picdir
 	else true; fi
 	$(COMPILE.c) $(srcdir)/cplus-dem.c $(OUTPUT_OPTION)
 
+./crc32.o: $(srcdir)/crc32.c config.h $(INCDIR)/ansidecl.h $(INCDIR)/libiberty.h
+	if [ x"$(PICFLAG)" != x ]; then \
+	  $(COMPILE.c) $(PICFLAG) $(srcdir)/crc32.c -o pic/$@; \
+	else true; fi
+	$(COMPILE.c) $(srcdir)/crc32.c $(OUTPUT_OPTION)
+
 ./dyn-string.o: $(srcdir)/dyn-string.c config.h $(INCDIR)/ansidecl.h \
 	$(INCDIR)/dyn-string.h $(INCDIR)/libiberty.h
 	if [ x"$(PICFLAG)" != x ]; then \
Index: libiberty/crc32.c
===================================================================
--- libiberty/crc32.c	(revision 0)
+++ libiberty/crc32.c	(revision 0)
@@ -0,0 +1,167 @@
+/* crc32.c
+   Copyright (C) 2009 Free Software Foundation, Inc.
+
+   This file is part of the libiberty library.
+
+   This file 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 2 of the License, or
+   (at your option) any later version.
+
+   In addition to the permissions in the GNU General Public License, the
+   Free Software Foundation gives you unlimited permission to link the
+   compiled version of this file into combinations with other programs,
+   and to distribute those combinations without any restriction coming
+   from the use of this file.  (The General Public License restrictions
+   do apply in other respects; for example, they cover modification of
+   the file, and distribution when not linked into a combined
+   executable.)
+
+   This program 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 this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "libiberty.h"
+
+/* This table was generated by the following program.  This matches
+   what gdb does.
+
+   #include <stdio.h>
+
+   int
+   main ()
+   {
+     int i, j;
+     unsigned int c;
+     int table[256];
+
+     for (i = 0; i < 256; i++)
+       {
+	 for (c = i << 24, j = 8; j > 0; --j)
+	   c = c & 0x80000000 ? (c << 1) ^ 0x04c11db7 : (c << 1);
+	 table[i] = c;
+       }
+
+     printf ("static const unsigned int crc32_table[] =\n{\n");
+     for (i = 0; i < 256; i += 4)
+       {
+	 printf ("  0x%08x, 0x%08x, 0x%08x, 0x%08x",
+		 table[i + 0], table[i + 1], table[i + 2], table[i + 3]);
+	 if (i + 4 < 256)
+	   putchar (',');
+	 putchar ('\n');
+       }
+     printf ("};\n");
+     return 0;
+   }
+
+   For more information on CRC, see, e.g.,
+   http://www.ross.net/crc/download/crc_v3.txt.  */
+
+static const unsigned int crc32_table[] =
+{
+  0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9,
+  0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
+  0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61,
+  0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
+  0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9,
+  0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
+  0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011,
+  0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
+  0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
+  0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
+  0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81,
+  0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
+  0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49,
+  0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
+  0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1,
+  0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
+  0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae,
+  0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
+  0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
+  0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
+  0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde,
+  0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
+  0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066,
+  0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
+  0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e,
+  0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
+  0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6,
+  0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
+  0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
+  0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
+  0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686,
+  0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
+  0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637,
+  0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
+  0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f,
+  0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
+  0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47,
+  0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
+  0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
+  0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
+  0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7,
+  0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
+  0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f,
+  0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
+  0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7,
+  0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
+  0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f,
+  0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
+  0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
+  0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
+  0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8,
+  0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
+  0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30,
+  0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
+  0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088,
+  0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
+  0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0,
+  0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
+  0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
+  0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
+  0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0,
+  0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
+  0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668,
+  0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
+};
+
+/*
+
+@deftypefn Extension unsigned int crc32 (const unsigned char *@var{buf}, int @var{len}, unsigned int @var{init})
+
+Compute the 32-bit CRC of @var{buf} which has length @var{len}.  The
+starting value is @var{init}; this may be used to compute the CRC of
+data split across multiple buffers by passing the return value of each
+call as the @var{init} parameter of the next.
+
+This is intended to match the CRC used by the @command{gdb} remote
+protocol for the @samp{qCRC} command.  In order to get the same
+results as gdb for a block of data, you must pass the first CRC
+parameter as @code{0xffffffff}.
+
+@end deftypefn
+
+*/
+
+unsigned int
+crc32 (const unsigned char *buf, int len, unsigned int init)
+{
+  unsigned int crc = init;
+  while (len--)
+    {
+      crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ *buf) & 255];
+      buf++;
+    }
+  return crc;
+}