Annotation of embedaddon/libpdel/io/boundary_fp.c, revision 1.1.1.1
1.1 misho 1:
2: /*
3: * Copyright (c) 2001-2002 Packet Design, LLC.
4: * All rights reserved.
5: *
6: * Subject to the following obligations and disclaimer of warranty,
7: * use and redistribution of this software, in source or object code
8: * forms, with or without modifications are expressly permitted by
9: * Packet Design; provided, however, that:
10: *
11: * (i) Any and all reproductions of the source or object code
12: * must include the copyright notice above and the following
13: * disclaimer of warranties; and
14: * (ii) No rights are granted, in any manner or form, to use
15: * Packet Design trademarks, including the mark "PACKET DESIGN"
16: * on advertising, endorsements, or otherwise except as such
17: * appears in the above copyright notice or in the software.
18: *
19: * THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
20: * TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO
21: * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING
22: * THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED
23: * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
24: * OR NON-INFRINGEMENT. PACKET DESIGN DOES NOT WARRANT, GUARANTEE,
25: * OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS
26: * OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY,
27: * RELIABILITY OR OTHERWISE. IN NO EVENT SHALL PACKET DESIGN BE
28: * LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE
29: * OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT,
30: * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL
31: * DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF
32: * USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY THEORY OF
33: * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
35: * THE USE OF THIS SOFTWARE, EVEN IF PACKET DESIGN IS ADVISED OF
36: * THE POSSIBILITY OF SUCH DAMAGE.
37: *
38: * Author: Archie Cobbs <archie@freebsd.org>
39: */
40:
41: #include <sys/types.h>
42: #include <sys/param.h>
43:
44: #include <stdio.h>
45: #include <stdlib.h>
46: #include <stdarg.h>
47: #include <string.h>
48: #include <assert.h>
49: #include <errno.h>
50:
51: #include "structs/structs.h"
52: #include "structs/type/array.h"
53:
54: #include "util/typed_mem.h"
55: #include "io/boundary_fp.h"
56:
57: #define MEM_TYPE "boundary_fp"
58:
59: #define MAX_BOUNDARY 255 /* must be less than 256 */
60:
61: /* Internal state per stream */
62: struct boundary_fp {
63: FILE *fp;
64: char bdry[MAX_BOUNDARY]; /* boundary string */
65: u_char fail[MAX_BOUNDARY]; /* failure function */
66: u_char buf[MAX_BOUNDARY]; /* input buffer data */
67: int closeit; /* close underlying stream */
68: int blen; /* boundary string length */
69: int nbuf; /* number chars in buffer */
70: int nmatch; /* length of the longest suffix
71: of buffer data that matches
72: a prefix of the boundary */
73: };
74:
75: /*
76: * Internal functions
77: */
78: static int boundary_read(void *cookie, char *buf, int len);
79: static int boundary_close(void *cookie);
80:
81: /*
82: * Create a FILE * that reads from another FILE *, stopping
83: * just after it reads in the supplied boundary string.
84: */
85: FILE *
86: boundary_fopen(FILE *fp, const char *boundary, int closeit)
87: {
88: struct boundary_fp *m;
89: int blen;
90: int i, j;
91:
92: /* Sanity check */
93: if ((blen = strlen(boundary)) > MAX_BOUNDARY) {
94: errno = EINVAL;
95: return (NULL);
96: }
97:
98: /* Create state structure */
99: if ((m = MALLOC(MEM_TYPE, sizeof(*m))) == NULL)
100: return (NULL);
101: memset(m, 0, sizeof(*m));
102: m->fp = fp;
103: m->blen = blen;
104: m->closeit = closeit;
105: memcpy(m->bdry, boundary, m->blen);
106:
107: /* Generate failure function (linear algorithms exist; this isn't) */
108: for (i = 2; i < m->blen; i++) {
109: for (j = 1; j < i && strncmp(m->bdry, m->bdry + j, i - j); j++);
110: m->fail[i] = i - j;
111: }
112:
113: /* Create new stream using methods below */
114: if ((fp = funopen(m, boundary_read,
115: NULL, NULL, boundary_close)) == NULL) {
116: FREE(MEM_TYPE, m);
117: return (NULL);
118: }
119:
120: /* Done */
121: return (fp);
122: }
123:
124: /*
125: * Read method.
126: */
127: static int
128: boundary_read(void *cookie, char *buf, int len)
129: {
130: struct boundary_fp *const m = cookie;
131: int nr;
132: int i;
133:
134: /* Sanity */
135: assert(m->nmatch <= m->nbuf);
136:
137: /* Have we got a complete boundary sitting in the buffer? */
138: if (m->nmatch == m->blen)
139: return (0);
140:
141: /* Return available data, if any (and shift buffer) */
142: if (m->nbuf > m->nmatch) {
143: len = MIN(len, m->nbuf - m->nmatch);
144: memcpy(buf, m->buf, len);
145: m->nbuf -= len;
146: memmove(m->buf, m->buf + len, m->nbuf);
147: return (len);
148: }
149:
150: /*
151: * Try to fill up the buffer from underlying stream. It is not
152: * possible to read past the end of a boundary at this point.
153: */
154: nr = fread(m->buf + m->nbuf, 1, m->blen - m->nbuf, m->fp);
155:
156: /* Check for EOF/error on underlying stream */
157: if (nr == 0) {
158: if (!ferror(m->fp))
159: errno = EFTYPE; /* no final boundary seen */
160: return (-1);
161: }
162:
163: /* Recompute match counter using failure links and new data */
164: for (i = m->nbuf; i < m->nbuf + nr; i++) {
165: while (m->nmatch > 0 && m->buf[i] != m->bdry[m->nmatch])
166: m->nmatch = m->fail[m->nmatch];
167: if (m->buf[i] == m->bdry[m->nmatch])
168: m->nmatch++;
169: }
170: m->nbuf += nr;
171:
172: /* Try again */
173: return (boundary_read(cookie, buf, len));
174: }
175:
176: /*
177: * Close method.
178: */
179: static int
180: boundary_close(void *cookie)
181: {
182: struct boundary_fp *const m = cookie;
183:
184: if (m->closeit)
185: fclose(m->fp);
186: FREE(MEM_TYPE, m);
187: return (0);
188: }
189:
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