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tar,smemcap: commonalyze checksumming code for tar header

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function                                             old     new   delta
chksum_and_xwrite_tar_header                           -      99     +99
writeheader                                          280     199     -81
chksum_and_xwrite                                    102       -    -102
------------------------------------------------------------------------------
(add/remove: 2/1 grow/shrink: 0/1 up/down: 99/-183)           Total: -84 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2021-08-20 17:58:49 +02:00
parent 38e9c8c95b
commit 62d5a1e56f
4 changed files with 39 additions and 44 deletions
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16
procps/smemcap.c
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@@ -29,7 +29,6 @@ struct fileblock {
static void writeheader(const char *path, struct stat *sb, int type)
{
struct tar_header_t header;
int i, sum;
memset(&header, 0, TAR_BLOCK_SIZE);
strcpy(header.name, path);
@@ -40,20 +39,7 @@ static void writeheader(const char *path, struct stat *sb, int type)
sprintf(header.size, "%o", (unsigned)sb->st_size);
sprintf(header.mtime, "%llo", sb->st_mtime & 077777777777LL);
header.typeflag = type;
strcpy(header.magic, "ustar "); /* like GNU tar */
/* Calculate and store the checksum (the sum of all of the bytes of
* the header). The checksum field must be filled with blanks for the
* calculation. The checksum field is formatted differently from the
* other fields: it has 6 digits, a NUL, then a space -- rather than
* digits, followed by a NUL like the other fields... */
header.chksum[7] = ' ';
sum = ' ' * 7;
for (i = 0; i < TAR_BLOCK_SIZE; i++)
sum += ((unsigned char*)&header)[i];
sprintf(header.chksum, "%06o", sum);
xwrite(STDOUT_FILENO, &header, TAR_BLOCK_SIZE);
chksum_and_xwrite_tar_header(STDOUT_FILENO, &header);
}
static void archivefile(const char *path)