/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 06:59

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	34	{
31	34	stream_A85D_state const ss = (stream_A85D_state ) st;
32
33	34	s_A85D_init_inline(ss);
34	34	return 0;
35	34	}
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	2.37k	{
43	2.37k	stream_A85D_state const ss = (stream_A85D_state ) st;
44	2.37k	register const byte *p = pr->ptr;
45	2.37k	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	2.37k	const byte rlimit = pr->limit - (last ? 0 : 7); / max EOD len + 1 */
51	2.37k	const byte *r = max(p, rlimit);
52	2.37k	byte *wlimit = pw->limit;
53	2.37k	int ccount = ss->odd;
54	2.37k	ulong word = ss->word;
55	2.37k	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	16.9k	while (r < pr->limit) {
60	14.5k	if (*++r == '~')
61	1.84k	while (r < pr->limit)
62	1.40k	if (*++r == '>') {
63		/* we have both characters of a complete EOD. */
64	0	rlimit = pr->limit; /* go ahead and process everything */
65	0	r = rlimit; /* break out of the while loops */
66	0	break;
67	0	}
68	14.5k	}
69	588k	while (p < rlimit) {
70	588k	int ch = *++p;
71	588k	uint ccode = ch - '!';
72
73	588k	if (ccode < 85) { /* catches ch < '!' as well */
74	584k	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	116k	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	116k	if (word >= 0x03030303 && ccode > 0) {
86	13	status = ERRC;
87	13	break;
88	13	}
89	116k	word = word * 85 + ccode;
90	116k	q[1] = (byte) (word >> 24);
91	116k	q[2] = (byte) (word >> 16);
92	116k	q[3] = (byte) ((uint) word >> 8);
93	116k	q[4] = (byte) word;
94	116k	q += 4;
95	116k	word = 0;
96	116k	ccount = 0;
97	467k	} else {
98	467k	word = word * 85 + ccode;
99	467k	++ccount;
100	467k	}
101	584k	} else if (ch == 'z' && ccount == 0) {
102	13	if (wlimit - q < 4) {
103	0	p--;
104	0	status = 1;
105	0	break;
106	0	}
107	13	q[1] = q[2] = q[3] = q[4] = 0,
108	13	q += 4;
109	3.41k	} else if (scan_char_decoder[ch] == ctype_space)
110	3.41k	DO_NOTHING;
111	1.75k	else if (ch == '~') {
112	1.71k	int i = 1;
113
114	1.71k	rlimit = pr->limit; /* Here we use the real "limit" */
115		/* Handle odd bytes. */
116	1.71k	if (p == rlimit) {
117	0	if (!last)
118	0	p--;
119	0	else if (ss->pdf_rules)
120	0	goto finish;
121	0	else
122	0	status = ERRC;
123	0	break;
124	0	}
125	1.71k	if ((int)(wlimit - q) < ccount - 1) {
126	2	status = 1;
127	2	p--;
128	2	break;
129	2	}
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	2.04k	while ((p + i <= rlimit) && (p[i] == 13 \|\| p[i] == 10))
139	330	i++;
140	1.71k	if (p + i <= rlimit && p[i] != '>') {
141	1.70k	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	1.70k	} else {
149	1.70k	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	1.70k	break;
156	1.70k	}
157	1.70k	}
158	12	finish:
159	12	if (p + i <= rlimit)
160	5	p += i; /* advance to the '>' */
161	7	else
162	7	p = rlimit; /* Can happen if the '>' is missing */
163	12	pw->ptr = q;
164	12	status = a85d_finish(ccount, word, pw);
165	12	q = pw->ptr;
166	12	break;
167	1.71k	} else { /* syntax error or exception */
168	35	status = ERRC;
169	35	break;
170	35	}
171	588k	}
172	2.37k	pw->ptr = q;
173	2.37k	if (status == 0 && last) {
174	43	if ((int)(wlimit - q) < ccount - 1)
175	0	status = 1;
176	43	else if (ss->require_eod)
177	43	status = ERRC;
178	0	else
179	0	status = a85d_finish(ccount, word, pw);
180	43	}
181	2.37k	pr->ptr = p;
182	2.37k	ss->odd = ccount;
183	2.37k	ss->word = word;
184	2.37k	return status;
185	2.37k	}
186		/* Handle the end of input data. */
187		static int
188		a85d_finish(int ccount, ulong word, stream_cursor_write * pw)
189	12	{
190		/* Assume there is enough room in the output buffer! */
191	12	byte *q = pw->ptr;
192	12	int status = EOFC;
193
194	12	switch (ccount) {
195	2	case 0:
196	2	break;
197	5	case 1: /* syntax error */
198	5	status = ERRC;
199	5	break;
200	3	case 2: /* 1 odd byte */
201	3	word = word * (85L * 85 * 85) + 85L * 85 * 85 - 1L;
202	3	goto o1;
203	1	case 3: /* 2 odd bytes */
204	1	word = word * (85L * 85) + 85L * 85L - 1L;
205	1	goto o2;
206	1	case 4: /* 3 odd bytes */
207	1	word = word * 85L + 84L;
208	1	q[3] = (byte) (word >> 8);
209	2	o2: q[2] = (byte) (word >> 16);
210	5	o1: q[1] = (byte) (word >> 24);
211	5	q += ccount - 1;
212	5	pw->ptr = q;
213	12	}
214	12	return status;
215	12	}
216
217		/* Stream template */
218		const stream_template s_A85D_template = {
219		&st_A85D_state, s_A85D_init, s_A85D_process, 2, 4
220		};