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/* Handle so called `shell archives'.
Copyright (C) 1994, 1995, 2007 Free Software Foundation, Inc.
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 3, 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "system.h"
/* Basic one-character encoding function to make a char printing. */
#define ENCODE_BYTE(Byte) ((((Byte) + 63) & 63) + ' ' + 1)
/* Buffer size for one line of output. */
#define LINE_BUFFER_SIZE 45
/*------------------------------------------.
| Output one GROUP of three bytes on FILE. |
`------------------------------------------*/
static void
write_encoded_bytes (group, file)
char *group;
FILE *file;
{
int c1, c2, c3, c4;
c1 = group[0] >> 2;
c2 = ((group[0] << 4) & (3 << 4)) | ((group[1] >> 4) & 15);
c3 = ((group[1] << 2) & (15 << 2)) | ((group[2] >> 6) & 3);
c4 = group[2] & 63;
putc (ENCODE_BYTE (c1), file);
putc (ENCODE_BYTE (c2), file);
putc (ENCODE_BYTE (c3), file);
putc (ENCODE_BYTE (c4), file);
}
/*--------------------------------------------------------------------.
| From FILE, refill BUFFER up to BUFFER_SIZE raw bytes, returning the |
| number of bytes read. |
`--------------------------------------------------------------------*/
static int
read_raw_bytes (file, buffer, buffer_size)
FILE *file;
char *buffer;
int buffer_size;
{
int character;
int counter;
for (counter = 0; counter < buffer_size; counter++)
{
character = getc (file);
if (character == EOF)
return counter;
buffer[counter] = character;
}
return buffer_size;
}
/*----------------------------------------------------.
| Copy INPUT file to OUTPUT file, while encoding it. |
`----------------------------------------------------*/
void
copy_file_encoded (input, output)
FILE *input;
FILE *output;
{
char buffer[LINE_BUFFER_SIZE];
int counter;
int number_of_bytes;
while (1)
{
number_of_bytes = read_raw_bytes (input, buffer, LINE_BUFFER_SIZE);
putc (ENCODE_BYTE (number_of_bytes), output);
for (counter = 0; counter < number_of_bytes; counter += 3)
write_encoded_bytes (&buffer[counter], output);
putc ('\n', output);
if (number_of_bytes == 0)
break;
}
}
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