/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 07:24

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	74	{
31	74	stream_A85D_state const ss = (stream_A85D_state ) st;
32
33	74	s_A85D_init_inline(ss);
34	74	return 0;
35	74	}
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	35.9k	{
43	35.9k	stream_A85D_state const ss = (stream_A85D_state ) st;
44	35.9k	register const byte *p = pr->ptr;
45	35.9k	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	35.9k	const byte rlimit = pr->limit - (last ? 0 : 7); / max EOD len + 1 */
51	35.9k	const byte *r = max(p, rlimit);
52	35.9k	byte *wlimit = pw->limit;
53	35.9k	int ccount = ss->odd;
54	35.9k	ulong word = ss->word;
55	35.9k	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	75.2k	while (r < pr->limit) {
60	39.2k	if (*++r == '~')
61	247k	while (r < pr->limit)
62	211k	if (*++r == '>') {
63		/* we have both characters of a complete EOD. */
64	3	rlimit = pr->limit; /* go ahead and process everything */
65	3	r = rlimit; /* break out of the while loops */
66	3	break;
67	3	}
68	39.2k	}
69	403k	while (p < rlimit) {
70	403k	int ch = *++p;
71	403k	uint ccode = ch - '!';
72
73	403k	if (ccode < 85) { /* catches ch < '!' as well */
74	366k	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	73.4k	if (wlimit - q < 4) {
80	120	p--;
81	120	status = 1;
82	120	break;
83	120	}
84		/* Check for overflow condition, throw ioerror if so */
85	73.3k	if (word >= 0x03030303 && ccode > 0) {
86	17	status = ERRC;
87	17	break;
88	17	}
89	73.2k	word = word * 85 + ccode;
90	73.2k	q[1] = (byte) (word >> 24);
91	73.2k	q[2] = (byte) (word >> 16);
92	73.2k	q[3] = (byte) ((uint) word >> 8);
93	73.2k	q[4] = (byte) word;
94	73.2k	q += 4;
95	73.2k	word = 0;
96	73.2k	ccount = 0;
97	293k	} else {
98	293k	word = word * 85 + ccode;
99	293k	++ccount;
100	293k	}
101	366k	} else if (ch == 'z' && ccount == 0) {
102	39	if (wlimit - q < 4) {
103	0	p--;
104	0	status = 1;
105	0	break;
106	0	}
107	39	q[1] = q[2] = q[3] = q[4] = 0,
108	39	q += 4;
109	36.5k	} else if (scan_char_decoder[ch] == ctype_space)
110	36.5k	DO_NOTHING;
111	35.5k	else if (ch == '~') {
112	35.5k	int i = 1;
113
114	35.5k	rlimit = pr->limit; /* Here we use the real "limit" */
115		/* Handle odd bytes. */
116	35.5k	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	35.5k	if ((int)(wlimit - q) < ccount - 1) {
126	9	status = 1;
127	9	p--;
128	9	break;
129	9	}
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	35.5k	while ((p + i <= rlimit) && (p[i] == 13 \|\| p[i] == 10))
139	35	i++;
140	35.5k	if (p + i <= rlimit && p[i] != '>') {
141	35.5k	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	35.5k	} else {
149	35.5k	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	35.5k	break;
156	35.5k	}
157	35.5k	}
158	20	finish:
159	20	if (p + i <= rlimit)
160	18	p += i; /* advance to the '>' */
161	2	else
162	2	p = rlimit; /* Can happen if the '>' is missing */
163	20	pw->ptr = q;
164	20	status = a85d_finish(ccount, word, pw);
165	20	q = pw->ptr;
166	20	break;
167	35.5k	} else { /* syntax error or exception */
168	50	status = ERRC;
169	50	break;
170	50	}
171	403k	}
172	35.9k	pw->ptr = q;
173	35.9k	if (status == 0 && last) {
174	30	if ((int)(wlimit - q) < ccount - 1)
175	0	status = 1;
176	30	else if (ss->require_eod)
177	29	status = ERRC;
178	1	else
179	1	status = a85d_finish(ccount, word, pw);
180	30	}
181	35.9k	pr->ptr = p;
182	35.9k	ss->odd = ccount;
183	35.9k	ss->word = word;
184	35.9k	return status;
185	35.9k	}
186		/* Handle the end of input data. */
187		static int
188		a85d_finish(int ccount, ulong word, stream_cursor_write * pw)
189	21	{
190		/* Assume there is enough room in the output buffer! */
191	21	byte *q = pw->ptr;
192	21	int status = EOFC;
193
194	21	switch (ccount) {
195	4	case 0:
196	4	break;
197	1	case 1: /* syntax error */
198	1	status = ERRC;
199	1	break;
200	5	case 2: /* 1 odd byte */
201	5	word = word * (85L * 85 * 85) + 85L * 85 * 85 - 1L;
202	5	goto o1;
203	6	case 3: /* 2 odd bytes */
204	6	word = word * (85L * 85) + 85L * 85L - 1L;
205	6	goto o2;
206	5	case 4: /* 3 odd bytes */
207	5	word = word * 85L + 84L;
208	5	q[3] = (byte) (word >> 8);
209	11	o2: q[2] = (byte) (word >> 16);
210	16	o1: q[1] = (byte) (word >> 24);
211	16	q += ccount - 1;
212	16	pw->ptr = q;
213	21	}
214	21	return status;
215	21	}
216
217		/* Stream template */
218		const stream_template s_A85D_template = {
219		&st_A85D_state, s_A85D_init, s_A85D_process, 2, 4
220		};