/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 07:06

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	8	{
31	8	stream_A85D_state const ss = (stream_A85D_state ) st;
32
33	8	s_A85D_init_inline(ss);
34	8	return 0;
35	8	}
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	913	{
43	913	stream_A85D_state const ss = (stream_A85D_state ) st;
44	913	register const byte *p = pr->ptr;
45	913	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	913	const byte rlimit = pr->limit - (last ? 0 : 7); / max EOD len + 1 */
51	913	const byte *r = max(p, rlimit);
52	913	byte *wlimit = pw->limit;
53	913	int ccount = ss->odd;
54	913	ulong word = ss->word;
55	913	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	6.82k	while (r < pr->limit) {
60	5.90k	if (*++r == '~')
61	0	while (r < pr->limit)
62	0	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	5.90k	}
69	791k	while (p < rlimit) {
70	790k	int ch = *++p;
71	790k	uint ccode = ch - '!';
72
73	790k	if (ccode < 85) { /* catches ch < '!' as well */
74	787k	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	157k	if (wlimit - q < 4) {
80	119	p--;
81	119	status = 1;
82	119	break;
83	119	}
84		/* Check for overflow condition, throw ioerror if so */
85	157k	if (word >= 0x03030303 && ccode > 0) {
86	3	status = ERRC;
87	3	break;
88	3	}
89	157k	word = word * 85 + ccode;
90	157k	q[1] = (byte) (word >> 24);
91	157k	q[2] = (byte) (word >> 16);
92	157k	q[3] = (byte) ((uint) word >> 8);
93	157k	q[4] = (byte) word;
94	157k	q += 4;
95	157k	word = 0;
96	157k	ccount = 0;
97	630k	} else {
98	630k	word = word * 85 + ccode;
99	630k	++ccount;
100	630k	}
101	787k	} else if (ch == 'z' && ccount == 0) {
102	11	if (wlimit - q < 4) {
103	0	p--;
104	0	status = 1;
105	0	break;
106	0	}
107	11	q[1] = q[2] = q[3] = q[4] = 0,
108	11	q += 4;
109	2.58k	} else if (scan_char_decoder[ch] == ctype_space)
110	2.58k	DO_NOTHING;
111	64	else if (ch == '~') {
112	46	int i = 1;
113
114	46	rlimit = pr->limit; /* Here we use the real "limit" */
115		/* Handle odd bytes. */
116	46	if (p == rlimit) {
117	2	if (!last)
118	0	p--;
119	2	else if (ss->pdf_rules)
120	0	goto finish;
121	2	else
122	2	status = ERRC;
123	2	break;
124	2	}
125	44	if ((int)(wlimit - q) < ccount - 1) {
126	0	status = 1;
127	0	p--;
128	0	break;
129	0	}
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	371	while ((p + i <= rlimit) && (p[i] == 13 \|\| p[i] == 10))
139	327	i++;
140	44	if (p + i <= rlimit && p[i] != '>') {
141	32	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	32	} else {
149	32	if (p + i == rlimit) {
150	2	if (last)
151	2	status = ERRC;
152	0	else
153	0	p--; /* we'll see the '~' after filling the buffer */
154	2	}
155	32	break;
156	32	}
157	32	}
158	12	finish:
159	12	if (p + i <= rlimit)
160	3	p += i; /* advance to the '>' */
161	9	else
162	9	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	44	} else { /* syntax error or exception */
168	18	status = ERRC;
169	18	break;
170	18	}
171	790k	}
172	913	pw->ptr = q;
173	913	if (status == 0 && last) {
174	35	if ((int)(wlimit - q) < ccount - 1)
175	0	status = 1;
176	35	else if (ss->require_eod)
177	34	status = ERRC;
178	1	else
179	1	status = a85d_finish(ccount, word, pw);
180	35	}
181	913	pr->ptr = p;
182	913	ss->odd = ccount;
183	913	ss->word = word;
184	913	return status;
185	913	}
186		/* Handle the end of input data. */
187		static int
188		a85d_finish(int ccount, ulong word, stream_cursor_write * pw)
189	13	{
190		/* Assume there is enough room in the output buffer! */
191	13	byte *q = pw->ptr;
192	13	int status = EOFC;
193
194	13	switch (ccount) {
195	2	case 0:
196	2	break;
197	5	case 1: /* syntax error */
198	5	status = ERRC;
199	5	break;
200	4	case 2: /* 1 odd byte */
201	4	word = word * (85L * 85 * 85) + 85L * 85 * 85 - 1L;
202	4	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	6	o1: q[1] = (byte) (word >> 24);
211	6	q += ccount - 1;
212	6	pw->ptr = q;
213	13	}
214	13	return status;
215	13	}
216
217		/* Stream template */
218		const stream_template s_A85D_template = {
219		&st_A85D_state, s_A85D_init, s_A85D_process, 2, 4
220		};