/src/ghostpdl/base/sa85d.c

Source (jump to first uncovered line)
/* Copyright (C) 2001-2023 Artifex Software, Inc.
   All Rights Reserved.

   This software is provided AS-IS with no warranty, either express or
   implied.

   This software is distributed under license and may not be copied,
   modified or distributed except as expressly authorized under the terms
   of the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  39 Mesa Street, Suite 108A, San Francisco,
   CA 94129, USA, for further information.
*/


/* ASCII85Decode filter */
#include "std.h"
#include "strimpl.h"
#include "sa85d.h"
#include "scanchar.h"

/* ------ ASCII85Decode ------ */

private_st_A85D_state();

/* Initialize the state */
static int
s_A85D_init(stream_state * st)
{
    stream_A85D_state *const ss = (stream_A85D_state *) st;

    s_A85D_init_inline(ss);
    return 0;
}

/* Process a buffer */
static int a85d_finish(int, ulong, stream_cursor_write *);
static 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;
    /* stop processing early unless the target is empty (last == true)  */
    /* to make sure we consume the EOD marker correctly. The EOD marker */
    /* might be as many as 6 characters after the last valid data char  */
    /* D <cr> <lf> '~' <cr> <lf> '>' where 'D' is a data character.     */
    const byte *rlimit = pr->limit - (last ? 0 : 7); /* max EOD len + 1 */
    const byte *r = max(p, rlimit);
    byte *wlimit = pw->limit;
    int ccount = ss->odd;
    ulong word = ss->word;
    int status = 0;

    /* scan to make sure that an EOD isn't fully contained in the */
    /* last part of the buffer (between rlimit and pr->limit).    */
    while (r < pr->limit) {
        if (*++r == '~')
            while (r < pr->limit)
                if (*++r == '>') {
                    /* we have both characters of a complete EOD. */
                    rlimit = pr->limit; /* go ahead and process everything */
                    r = rlimit;   /* break out of the while loops */
                    break;
                }
    }
    while (p < rlimit) {
        int ch = *++p;
        uint ccode = ch - '!';

        if (ccode < 85) { /* catches ch < '!' as well */
            if (ccount == 4) {
                /*
                 * We've completed a 32-bit group.  Make sure we have
                 * room for it in the output.
                 */
                if (wlimit - q < 4) {
                    p--;
                    status = 1;
                    break;
                }
                /* Check for overflow condition, throw ioerror if so */
                if (word >= 0x03030303 && ccode > 0) {
                    status = ERRC;
                    break;
                }
                word = word * 85 + ccode;
                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 {
                word = word * 85 + ccode;
                ++ccount;
            }
        } 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 == '~') {
            int i = 1;

            rlimit = pr->limit;   /* Here we use the real "limit" */
            /* Handle odd bytes. */
            if (p == rlimit) {
                if (!last)
                  p--;
                else if (ss->pdf_rules)
                  goto finish;
                else
                    status = ERRC;
                break;
            }
            if ((int)(wlimit - q) < ccount - 1) {
                status = 1;
                p--;
                break;
            }

            /* According to PLRM 3rd, if the A85 filter encounters '~',
             * the next character must be '>'.
             * And any other characters should raise an ioerror.
             * But Adobe Acrobat allows CR/LF between ~ and >.
             * So we allow CR/LF between them. */
            /* PDF further relaxes the requirements and accepts bare '~'.
             */
            while ((p + i <= rlimit) && (p[i] == 13 || p[i] == 10))
                i++;
            if (p + i <= rlimit && p[i] != '>') {
                if (ss->pdf_rules) {
                    if (p[i] == 13 || p[i] == 10) {
                        if (!last)
                            break;
                    } else {
                        p--;
                    }
                } else {
                    if (p + i == rlimit) {
                        if (last)
                            status = ERRC;
                        else
                            p--; /* we'll see the '~' after filling the buffer */
                    }
                    break;
                }
            }
          finish:
            if (p + i <= rlimit)
                p += i;    /* advance to the '>' */
            else
                p = rlimit; /* Can happen if the '>' is missing */
            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 if (ss->require_eod)
            status = ERRC;
        else
            status = a85d_finish(ccount, word, pw);
    }
    pr->ptr = p;
    ss->odd = ccount;
    ss->word = word;
    return status;
}
/* Handle the end of input data. */
static 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) + 85L * 85 * 85 - 1L;
            goto o1;
        case 3:   /* 2 odd bytes */
            word = word * (85L * 85) + 85L * 85L - 1L;
            goto o2;
        case 4:   /* 3 odd bytes */
            word = word * 85L + 84L;
            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
};

Coverage Report

Created: 2025-06-10 07:15

Line	Count	Source (jump to first uncovered line)
1		/* Copyright (C) 2001-2023 Artifex Software, Inc.
2		All Rights Reserved.
3
4		This software is provided AS-IS with no warranty, either express or
5		implied.
6
7		This software is distributed under license and may not be copied,
8		modified or distributed except as expressly authorized under the terms
9		of the license contained in the file LICENSE in this distribution.
10
11		Refer to licensing information at http://www.artifex.com or contact
12		Artifex Software, Inc., 39 Mesa Street, Suite 108A, San Francisco,
13		CA 94129, USA, for further information.
14		*/
15
16
17		/* ASCII85Decode filter */
18		#include "std.h"
19		#include "strimpl.h"
20		#include "sa85d.h"
21		#include "scanchar.h"
22
23		/* ------ ASCII85Decode ------ */
24
25		private_st_A85D_state();
26
27		/* Initialize the state */
28		static int
29		s_A85D_init(stream_state * st)
30	67	{
31	67	stream_A85D_state const ss = (stream_A85D_state ) st;
32
33	67	s_A85D_init_inline(ss);
34	67	return 0;
35	67	}
36
37		/* Process a buffer */
38		static int a85d_finish(int, ulong, stream_cursor_write *);
39		static int
40		s_A85D_process(stream_state * st, stream_cursor_read * pr,
41		stream_cursor_write * pw, bool last)
42	44.2k	{
43	44.2k	stream_A85D_state const ss = (stream_A85D_state ) st;
44	44.2k	register const byte *p = pr->ptr;
45	44.2k	register byte *q = pw->ptr;
46		/* stop processing early unless the target is empty (last == true) */
47		/* to make sure we consume the EOD marker correctly. The EOD marker */
48		/* might be as many as 6 characters after the last valid data char */
49		/* D <cr> <lf> '~' <cr> <lf> '>' where 'D' is a data character. */
50	44.2k	const byte rlimit = pr->limit - (last ? 0 : 7); / max EOD len + 1 */
51	44.2k	const byte *r = max(p, rlimit);
52	44.2k	byte *wlimit = pw->limit;
53	44.2k	int ccount = ss->odd;
54	44.2k	ulong word = ss->word;
55	44.2k	int status = 0;
56
57		/* scan to make sure that an EOD isn't fully contained in the */
58		/* last part of the buffer (between rlimit and pr->limit). */
59	100k	while (r < pr->limit) {
60	56.0k	if (*++r == '~')
61	295k	while (r < pr->limit)
62	252k	if (*++r == '>') {
63		/* we have both characters of a complete EOD. */
64	72	rlimit = pr->limit; /* go ahead and process everything */
65	72	r = rlimit; /* break out of the while loops */
66	72	break;
67	72	}
68	56.0k	}
69	377k	while (p < rlimit) {
70	377k	int ch = *++p;
71	377k	uint ccode = ch - '!';
72
73	377k	if (ccode < 85) { /* catches ch < '!' as well */
74	331k	if (ccount == 4) {
75		/*
76		* We've completed a 32-bit group. Make sure we have
77		* room for it in the output.
78		*/
79	66.4k	if (wlimit - q < 4) {
80	104	p--;
81	104	status = 1;
82	104	break;
83	104	}
84		/* Check for overflow condition, throw ioerror if so */
85	66.3k	if (word >= 0x03030303 && ccode > 0) {
86	17	status = ERRC;
87	17	break;
88	17	}
89	66.3k	word = word * 85 + ccode;
90	66.3k	q[1] = (byte) (word >> 24);
91	66.3k	q[2] = (byte) (word >> 16);
92	66.3k	q[3] = (byte) ((uint) word >> 8);
93	66.3k	q[4] = (byte) word;
94	66.3k	q += 4;
95	66.3k	word = 0;
96	66.3k	ccount = 0;
97	265k	} else {
98	265k	word = word * 85 + ccode;
99	265k	++ccount;
100	265k	}
101	331k	} else if (ch == 'z' && ccount == 0) {
102	68	if (wlimit - q < 4) {
103	0	p--;
104	0	status = 1;
105	0	break;
106	0	}
107	68	q[1] = q[2] = q[3] = q[4] = 0,
108	68	q += 4;
109	45.6k	} else if (scan_char_decoder[ch] == ctype_space)
110	45.6k	DO_NOTHING;
111	43.8k	else if (ch == '~') {
112	43.8k	int i = 1;
113
114	43.8k	rlimit = pr->limit; /* Here we use the real "limit" */
115		/* Handle odd bytes. */
116	43.8k	if (p == rlimit) {
117	1	if (!last)
118	0	p--;
119	1	else if (ss->pdf_rules)
120	0	goto finish;
121	1	else
122	1	status = ERRC;
123	1	break;
124	1	}
125	43.8k	if ((int)(wlimit - q) < ccount - 1) {
126	12	status = 1;
127	12	p--;
128	12	break;
129	12	}
130
131		/* According to PLRM 3rd, if the A85 filter encounters '~',
132		* the next character must be '>'.
133		* And any other characters should raise an ioerror.
134		* But Adobe Acrobat allows CR/LF between ~ and >.
135		* So we allow CR/LF between them. */
136		/* PDF further relaxes the requirements and accepts bare '~'.
137		*/
138	43.8k	while ((p + i <= rlimit) && (p[i] == 13 \|\| p[i] == 10))
139	50	i++;
140	43.8k	if (p + i <= rlimit && p[i] != '>') {
141	43.7k	if (ss->pdf_rules) {
142	0	if (p[i] == 13 \|\| p[i] == 10) {
143	0	if (!last)
144	0	break;
145	0	} else {
146	0	p--;
147	0	}
148	43.7k	} else {
149	43.7k	if (p + i == rlimit) {
150	1	if (last)
151	1	status = ERRC;
152	0	else
153	0	p--; /* we'll see the '~' after filling the buffer */
154	1	}
155	43.7k	break;
156	43.7k	}
157	43.7k	}
158	23	finish:
159	23	if (p + i <= rlimit)
160	20	p += i; /* advance to the '>' */
161	3	else
162	3	p = rlimit; /* Can happen if the '>' is missing */
163	23	pw->ptr = q;
164	23	status = a85d_finish(ccount, word, pw);
165	23	q = pw->ptr;
166	23	break;
167	43.8k	} else { /* syntax error or exception */
168	44	status = ERRC;
169	44	break;
170	44	}
171	377k	}
172	44.2k	pw->ptr = q;
173	44.2k	if (status == 0 && last) {
174	45	if ((int)(wlimit - q) < ccount - 1)
175	0	status = 1;
176	45	else if (ss->require_eod)
177	44	status = ERRC;
178	1	else
179	1	status = a85d_finish(ccount, word, pw);
180	45	}
181	44.2k	pr->ptr = p;
182	44.2k	ss->odd = ccount;
183	44.2k	ss->word = word;
184	44.2k	return status;
185	44.2k	}
186		/* Handle the end of input data. */
187		static int
188		a85d_finish(int ccount, ulong word, stream_cursor_write * pw)
189	24	{
190		/* Assume there is enough room in the output buffer! */
191	24	byte *q = pw->ptr;
192	24	int status = EOFC;
193
194	24	switch (ccount) {
195	5	case 0:
196	5	break;
197	2	case 1: /* syntax error */
198	2	status = ERRC;
199	2	break;
200	5	case 2: /* 1 odd byte */
201	5	word = word * (85L * 85 * 85) + 85L * 85 * 85 - 1L;
202	5	goto o1;
203	7	case 3: /* 2 odd bytes */
204	7	word = word * (85L * 85) + 85L * 85L - 1L;
205	7	goto o2;
206	5	case 4: /* 3 odd bytes */
207	5	word = word * 85L + 84L;
208	5	q[3] = (byte) (word >> 8);
209	12	o2: q[2] = (byte) (word >> 16);
210	17	o1: q[1] = (byte) (word >> 24);
211	17	q += ccount - 1;
212	17	pw->ptr = q;
213	24	}
214	24	return status;
215	24	}
216
217		/* Stream template */
218		const stream_template s_A85D_template = {
219		&st_A85D_state, s_A85D_init, s_A85D_process, 2, 4
220		};