1 /*
2 Terminal Mixer - multi-point multi-user access to terminal applications
3 Copyright (C) 2007 Lluís Batlle i Rossell
4
5 Please find the license in the provided COPYING file.
6 */
7 #include <stdlib.h>
8 #include <stdio.h>
9 #include <string.h>
10 #include "main.h"
11
12 #include "filter.h"
13
add_ffilter(struct FilterRules * fr,struct FFilter * ff)14 void add_ffilter(struct FilterRules *fr, struct FFilter *ff)
15 {
16 fr->nfilters += 1;
17 fr->filters = (struct FFilter **) realloc(fr->filters,
18 sizeof(*fr->filters) * fr->nfilters);
19 if (fr->filters == 0) error("realloc failed.");
20
21 fr->filters[fr->nfilters-1] = ff;
22 ff->matched = 0;
23 }
24
new_filter_rules()25 struct FilterRules * new_filter_rules()
26 {
27 struct FilterRules *fr;
28 fr = (struct FilterRules *) malloc(sizeof(*fr));
29 if (fr == 0) error("malloc failed.");
30
31 fr->nfilters = 0;
32 fr->filters = 0; /* null for realloc */
33 fr->fbuffer = 0;
34 fr->fbuffer_len = 0;
35 fr->fbuffer_allocated = 0;
36
37 return fr;
38 }
39
40 /* We want to access index even before the 'buffer' limits.
41 * Those are at fr->fbuffer, and referred as -X indexes. */
get_char(struct FilterRules * fr,const unsigned char * buffer,int pos)42 static int get_char(struct FilterRules *fr, const unsigned char *buffer, int pos)
43 {
44 if (pos >= 0)
45 return buffer[pos];
46 else
47 {
48 if (-pos > fr->fbuffer_len)
49 return -1;
50 /* pos is negative */
51 return fr->fbuffer[fr->fbuffer_len + pos];
52 }
53 }
54
set_char(struct FilterRules * fr,unsigned char * buffer,int pos,int c)55 static int set_char(struct FilterRules *fr, unsigned char *buffer, int pos, int c)
56 {
57 if (pos >= 0)
58 {
59 buffer[pos] = c;
60 return buffer[pos];
61 }
62 else
63 {
64 if (-pos > fr->fbuffer_len)
65 return -1;
66 fr->fbuffer[fr->fbuffer_len - pos] = c;
67 return fr->fbuffer[fr->fbuffer_len - pos];
68 }
69 }
70
71 /* Return 1 if matches */
apply_ffilter(struct FilterRules * fr,struct FFilter * ff,char * obuf,int * olen,const unsigned char * buffer,int pos)72 static int apply_ffilter(struct FilterRules *fr, struct FFilter *ff,
73 char *obuf, int *olen, const unsigned char *buffer, int pos)
74 {
75 int res;
76
77 res = ff->function(ff, buffer[pos]);
78 if (res)
79 {
80 /* String matches */
81 if (ff->callback)
82 {
83 int shift;
84 shift = pos - ff->matched;
85 /* Call callback */
86 ff->callback(fr, ff, obuf, olen, buffer, shift);
87 }
88 return 1;
89 }
90 return 0;
91 }
92
reset_matched(struct FilterRules * fr)93 static void reset_matched(struct FilterRules *fr)
94 {
95 int i;
96 for (i=0; i < fr->nfilters; ++i)
97 {
98 struct FFilter *ff;
99 ff = fr->filters[i];
100 ff->matched = 0;
101 if (ff->reset)
102 ff->reset(ff);
103 }
104 }
105
filter_stream(struct FilterRules * fr,char * obuf,int * olen,const char * buffer,int len)106 void filter_stream(struct FilterRules *fr, char *obuf, int *olen, const char *buffer, int len)
107 {
108 int i;
109
110 int ipos;
111 int max_matched;
112
113 *olen = 0;
114 ipos = - fr->fbuffer_len;
115 max_matched = fr->fbuffer_len;
116 for(i=0; i< len; ++i)
117 { /* each char */
118 int j;
119 int old_max_matched = max_matched;
120 int found = 0;
121 max_matched = 0;
122 /*printf("Try '%c'...\n", buffer[i]);*/
123 for (j=0; j < fr->nfilters; ++j)
124 {
125 struct FFilter *ff;
126 ff = fr->filters[j];
127 found = apply_ffilter(fr, ff, obuf, olen, buffer, i);
128 max_matched = max(max_matched, ff->matched);
129 if (found)
130 break;
131 }
132 /* Some chars may not be needed for the filters
133 * already. */
134 /*printf("ipos: %i\n", ipos);*/
135 if (found)
136 {
137 /*printf("[match!]\n");*/
138 reset_matched(fr);
139 /* The longest string will be matched, sure. Right?*/
140 ipos += max_matched;
141 max_matched = 0;
142 }
143 else
144 {
145 int freed = old_max_matched + 1 /* new char */ - max_matched;
146 for(j=0; j < freed; ++j)
147 {
148 obuf[(*olen)++] = get_char(fr, buffer, ipos++);
149 }
150 }
151 }
152 if (max_matched > fr->fbuffer_allocated)
153 {
154 fr->fbuffer = realloc(fr->fbuffer, max_matched);
155 if (fr->fbuffer == 0) error("Cannot allocate fbuffer");
156 }
157 /* Copy only new data from buffer */
158 {
159 int start_new_data;
160 int size_cpy;
161 int offset;
162 size_cpy = max_matched;
163 start_new_data = len - max_matched;
164 offset = 0;
165 if (start_new_data < 0)
166 {
167 offset += (-start_new_data);
168 size_cpy -= (-start_new_data);
169 start_new_data = 0;
170 }
171 memcpy(fr->fbuffer + offset, buffer + start_new_data, size_cpy);
172 fr->fbuffer_len = max_matched;
173 }
174 }
175
filter_flush(struct FilterRules * fr,char * obuf,int * olen)176 void filter_flush(struct FilterRules *fr, char *obuf, int *olen)
177 {
178 memcpy(obuf, fr->fbuffer, fr->fbuffer_len);
179 *olen = fr->fbuffer_len;
180 fr->fbuffer_len = 0;
181 }
182