[Easytag-mailing] adding features to easytag.

[oliver <oliver are-b org>]

Hi,

I was working on adding some features to easytag and emailed jerome 
about this a week ago. I still haven't receieved a reply so I'm going to 
ask here.

I wanted to add (among others) crc32 support. My idea was to have the 
option to set the crc32 into the comment field, if disired.

I added the appropiate option/buttons etc.

Then I took cksfv and extracted the crc32.c and heavly modified it to 
suit this projects needs. I created a new crc32.c and a crc32.h. I then 
made a little test.c to see if the newly created object would work. 
Everything seemd to work fine compiling test as gcc -o test crc32.c 
test.c and #including "crc32" at the top of test.c.

Then I added the crc32.c and crc32.h files to the easytag0.27.1 source 
tree. I'm unaware of the workings of autoconf etc and updated the 
Makefile.am and Makefile.im to atleast create a proper Makefile after 
the configure. here's the additions.

<snip>
easytag_SOURCES = \
<snip>
 charset.h \
 crc32.c \
 crc32.h \
 easytag.c \
<snip>
am_easytag_OBJECTS = about.$(OBJEXT) ape_tag.$(OBJEXT) bar.$(OBJEXT) \
	browser.$(OBJEXT) cddb.$(OBJEXT) charset.$(OBJEXT) \ crc32.$(OBJEXT) 
easytag.$(OBJEXT) et_core.$(OBJEXT) \
<snip>

I then configured and compiled the program again (without ANY patch that 
I created applied) and it compiled and linked just fine. Installing was 
without a problem either but when running the app it just crashed. I did 
not use any function from the added object, nor did I include the 
crc32.h header in any file. This seems to be working just fine. The next 
step was to include the crc32.h in id3_tag.c to use the added function. 
This also compiled, linked and runned fine.

Next I just called the function, wich results in an easytag that does no 
longer work. Of course it could be caused by my addition not beeing 
executed properly, however, makeing a simple test program, it just works 
fine.

I attached the crc32.c crc32.h and the test.c I used as a test app.
syntax: test <file>
will show the crc32 value of <file>

I modified id3_tag.c as follows:

addeded
#include "crc32.h"

and in
gboolean Id3tag_Read_File_Tag (gchar *filename, File_Tag *FileTag)
+    unsigned long val;

aswell as after the 'fopen'
    if ( (file=fopen(filename,"r"))==NULL )
    {
        g_print(_("ERROR while opening file: '%s' 
(%s).\n\a"),filename,g_strerror(errno));
        return FALSE;
    }
+    crc32(file, &val);
fclose(file); // We close it cause id3lib opens/closes file itself


this allready results in failure. I could try using a gtk unsigned long, 
but I doubt it would help much as this should simply work.

any help greatly appreciated.

oliver

#include <stdio.h>
#include <fcntl.h>
#include "crc32.h"

int main(int argc, char *argv[]) {
	FILE *fd;
	unsigned long val;
	printf("Massive crc32 checker\n");
	if (argc == 2) {
		printf("argv: %s\n", argv[1]);
		if ((fd = fopen(argv[1], "rbS")) == NULL) {
			fprintf(stderr, "Error while opening file: '%s'\n", argv[1]);
			return 0;
		} else {
			if (crc32(fd, &val)) {
				fprintf(stderr, "Error while performing crc32\n");
			} else {
				printf("%.8lx\n", val);
			}
			return 1;
		}
	}
	return 0;
}

/* crc32.h - the crc check algorithm for cksfv modified by oliver for easytag
   
   Copyright (C) 2000 Bryan Call <bc fodder org>
   Copyright (C) 2003 Oliver Schinagl <oliver are-b org>

   This program 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.

   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., 675 Mass Ave, Cambridge, MA 02139, USA. */


#define BUFFERSIZE 16384   /* (16k) buffer size for reading from the file */

static const unsigned long crctable[256] = {
  0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
  0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
  0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
  0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
  0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
  0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
  0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
  0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
  0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
  0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
  0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
  0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
  0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
  0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
  0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
  0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
  0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
  0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
  0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
  0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
  0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
  0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
  0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
  0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
  0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
  0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
  0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
  0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
  0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
  0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
  0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
  0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
  0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
  0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
  0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
  0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
  0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
  0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
  0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
  0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
  0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
  0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
  0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
  0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
  0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
  0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
  0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
  0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
  0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
  0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
  0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
  0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
  0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
  0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
  0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
  0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
  0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
  0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
  0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
  0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
  0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
  0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
  0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
  0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d,
};

int crc32(register FILE *fd, unsigned long *main_val);

/* crc32.c - the crc check algorithm for cksfv modified by oliver for easytag
   
   Copyright (C) 2000 Bryan Call <bc fodder org>
   Copyright (C) 2003 Oliver Schinagl <oliver are-b org>

   This program 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.

   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., 675 Mass Ave, Cambridge, MA 02139, USA. */

#include <stdio.h>
#include "crc32.h"

int crc32(register FILE *fd, unsigned long *main_val)
{
  char                  buf[BUFFERSIZE], *p;
  int                   nr;
  unsigned long         crc = ~0, crc32_total = ~0;
	
  while ((nr = fread(buf, sizeof(char), sizeof(buf), fd)) > 0)
    for (p = buf; nr--; ++p) {
      crc = (crc >> 8) ^ crctable[(crc ^ *p) & 0xff];
      crc32_total = (crc >> 8) ^ crctable[(crc32_total ^ *p) & 0xff];
    }
  if (nr < 0)
    return 1;

  *main_val = ~crc;
  return 0;
}