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/* Copyright (C) 1999 Aladdin Enterprises. All rights reserved.
This software is licensed to a single customer by Artifex Software Inc.
under the terms of a specific OEM agreement.
*/
/*$RCSfile$ $Revision$ */
/* ASCII85Decode filter */
#include "std.h"
#include "strimpl.h"
#include "sa85d.h"
#include "scanchar.h"
/* ------ ASCII85Decode ------ */
private_st_A85D_state();
/* Initialize the state */
private int
s_A85D_init(stream_state * st)
{
stream_A85D_state *const ss = (stream_A85D_state *) st;
return s_A85D_init_inline(ss);
}
/* Process a buffer */
private int a85d_finish(P3(int, ulong, stream_cursor_write *));
private int
s_A85D_process(stream_state * st, stream_cursor_read * pr,
stream_cursor_write * pw, bool last)
{
stream_A85D_state *const ss = (stream_A85D_state *) st;
register const byte *p = pr->ptr;
register byte *q = pw->ptr;
const byte *rlimit = pr->limit;
byte *wlimit = pw->limit;
int ccount = ss->odd;
ulong word = ss->word;
int status = 0;
while (p < rlimit) {
int ch = *++p;
uint ccode = ch - '!';
if (ccode < 85) { /* catches ch < '!' as well */
if (wlimit - q < 4) {
p--;
status = 1;
break;
}
word = word * 85 + ccode;
if (++ccount == 5) {
q[1] = (byte) (word >> 24);
q[2] = (byte) (word >> 16);
q[3] = (byte) ((uint) word >> 8);
q[4] = (byte) word;
q += 4;
word = 0;
ccount = 0;
}
} else if (ch == 'z' && ccount == 0) {
if (wlimit - q < 4) {
p--;
status = 1;
break;
}
q[1] = q[2] = q[3] = q[4] = 0,
q += 4;
} else if (scan_char_decoder[ch] == ctype_space)
DO_NOTHING;
else if (ch == '~') {
/* Handle odd bytes. */
if (p == rlimit) {
if (last)
status = ERRC;
else
p--;
break;
}
if ((int)(wlimit - q) < ccount - 1) {
status = 1;
p--;
break;
}
if (*++p != '>') {
status = ERRC;
break;
}
pw->ptr = q;
status = a85d_finish(ccount, word, pw);
q = pw->ptr;
break;
} else { /* syntax error or exception */
status = ERRC;
break;
}
}
pw->ptr = q;
if (status == 0 && last) {
if ((int)(wlimit - q) < ccount - 1)
status = 1;
else
status = a85d_finish(ccount, word, pw);
}
pr->ptr = p;
ss->odd = ccount;
ss->word = word;
return status;
}
/* Handle the end of input data. */
private int
a85d_finish(int ccount, ulong word, stream_cursor_write * pw)
{
/* Assume there is enough room in the output buffer! */
byte *q = pw->ptr;
int status = EOFC;
switch (ccount) {
case 0:
break;
case 1: /* syntax error */
status = ERRC;
break;
case 2: /* 1 odd byte */
word = word * (85L * 85 * 85) + 0xffffffL;
goto o1;
case 3: /* 2 odd bytes */
word = word * (85L * 85) + 0xffffL;
goto o2;
case 4: /* 3 odd bytes */
word = word * 85 + 0xffL;
q[3] = (byte) (word >> 8);
o2: q[2] = (byte) (word >> 16);
o1: q[1] = (byte) (word >> 24);
q += ccount - 1;
pw->ptr = q;
}
return status;
}
/* Stream template */
const stream_template s_A85D_template = {
&st_A85D_state, s_A85D_init, s_A85D_process, 2, 4
};
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