1 files changed, 130 insertions, 0 deletions
diff --git a/src/crc32.c b/src/crc32.c
new file mode 100755
index 0000000..bd68609
--- /dev/null
+++ b/src/crc32.c
@@ -0,0 +1,130 @@
+/* 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 <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdio.h>
+#include "crc32.h"
+
+/*
+ * Initial crc32 function
+ * This function was renamed from crc32(...) to crc32_easytag(...) to avoid a
+ * strange problem with some gtk theme that may use the same name of function.
+ */
+int crc32_easytag(register int fd, unsigned long *main_val)
+{
+    char          buf[BUFFERSIZE], *p;
+    int           nr;
+    unsigned long crc = ~0, crc32_total = ~0;
+
+    while ((nr = read(fd, &buf, sizeof(buf))) > 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;
+}
+
+
+
+/*
+ * Calculate the CRC-32 value of audio data (doesn't read the ID3v2 and ID3v1 tags).
+ * Return 0 if OK
+ */
+int crc32_file_with_ID3_tag(char *filename, unsigned long *main_val)
+{
+    char          buf[BUFFERSIZE], *p;
+    int           nr;
+    unsigned long crc = ~0, crc32_total = ~0;
+    FILE         *fd;
+    unsigned char tmp_id3[4];
+    int           id3v2size = 0;
+    struct        stat statbuf;
+    unsigned long size = 0;
+    int           has_id3v1 = 0;
+
+
+    if (!filename)
+        return 1;
+
+    stat(filename,&statbuf);
+    size = statbuf.st_size;
+
+    if ( (fd = fopen(filename,"r"))==NULL )
+        return 1;
+
+    // Check if there is an ID3v1 tag...
+    fseek(fd, -128, SEEK_END);
+    if (fread(tmp_id3, 1, 3, fd) != 3)
+        return 1;
+    if (tmp_id3[0] == 'T' && tmp_id3[1] == 'A' && tmp_id3[2] == 'G')
+        has_id3v1 = 1;
+
+
+    // Check if there is an ID3v2 tag...
+    fseek(fd, 0L, SEEK_SET);
+    if (fread(tmp_id3, 1, 4, fd) != 4)
+        return 1;
+    // Calculate ID3v2 length
+    if (tmp_id3[0] == 'I' && tmp_id3[1] == 'D' && tmp_id3[2] == '3' && tmp_id3[3] < 0xFF)
+    {
+        // id3v2 tag skipeer $49 44 33 yy yy xx zz zz zz zz [zz size]
+        fseek(fd, 2, SEEK_CUR); // Size is 6-9 position
+        if (fread(tmp_id3, 1, 4, fd) != 4)
+            return 1;
+        id3v2size = 10 + ( (long)(tmp_id3[3])        | ((long)(tmp_id3[2]) << 7)
+                        | ((long)(tmp_id3[1]) << 14) | ((long)(tmp_id3[0]) << 21) );
+
+        fseek(fd, id3v2size, SEEK_SET);
+        size = size - id3v2size;
+    }else
+    {
+        fseek(fd, 0L, SEEK_SET);
+    }
+
+    while ((nr = fread(buf, sizeof(char), sizeof(buf), fd)) > 0)
+    {
+        if (has_id3v1 && nr <= 128) // We are reading end of ID3v1 tag
+            break;
+        if ( has_id3v1 && ((size=size-nr) < 128) ) // ID3v1 tag is in the current buf
+            nr = nr - 128 + size;
+
+        for (p = buf; nr--; ++p)
+        {
+            crc = (crc >> 8) ^ crctable[(crc ^ *p) & 0xff];
+            crc32_total = (crc >> 8) ^ crctable[(crc32_total ^ *p) & 0xff];
+        }
+    }
+
+    fclose(fd);
+
+    if (nr < 0)
+        return 1;
+
+    *main_val = ~crc;
+
+    return 0;
+}