File: | src/usr.bin/less/less/../jump.c |
Warning: | line 119, column 7 Although the value stored to 'len' is used in the enclosing expression, the value is never actually read from 'len' |
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1 | /* |
2 | * Copyright (C) 1984-2012 Mark Nudelman |
3 | * Modified for use with illumos by Garrett D'Amore. |
4 | * Copyright 2014 Garrett D'Amore <garrett@damore.org> |
5 | * |
6 | * You may distribute under the terms of either the GNU General Public |
7 | * License or the Less License, as specified in the README file. |
8 | * |
9 | * For more information, see the README file. |
10 | */ |
11 | |
12 | /* |
13 | * Routines which jump to a new location in the file. |
14 | */ |
15 | |
16 | #include "less.h" |
17 | #include "position.h" |
18 | |
19 | extern int jump_sline; |
20 | extern int squished; |
21 | extern int screen_trashed; |
22 | extern int sc_width, sc_height; |
23 | extern int show_attn; |
24 | extern int top_scroll; |
25 | |
26 | /* |
27 | * Jump to the end of the file. |
28 | */ |
29 | void |
30 | jump_forw(void) |
31 | { |
32 | off_t pos; |
33 | off_t end_pos; |
34 | |
35 | if (ch_end_seek()) { |
36 | error("Cannot seek to end of file", NULL((void *)0)); |
37 | return; |
38 | } |
39 | /* |
40 | * Note; lastmark will be called later by jump_loc, but it fails |
41 | * because the position table has been cleared by pos_clear below. |
42 | * So call it here before calling pos_clear. |
43 | */ |
44 | lastmark(); |
45 | /* |
46 | * Position the last line in the file at the last screen line. |
47 | * Go back one line from the end of the file |
48 | * to get to the beginning of the last line. |
49 | */ |
50 | pos_clear(); |
51 | end_pos = ch_tell(); |
52 | pos = back_line(end_pos); |
53 | if (pos == -1) { |
54 | jump_loc(0, sc_height-1); |
55 | } else { |
56 | jump_loc(pos, sc_height-1); |
57 | if (position(sc_height-1) != end_pos) |
58 | repaint(); |
59 | } |
60 | } |
61 | |
62 | /* |
63 | * Jump to line n in the file. |
64 | */ |
65 | void |
66 | jump_back(off_t linenum) |
67 | { |
68 | off_t pos; |
69 | PARG parg; |
70 | |
71 | /* |
72 | * Find the position of the specified line. |
73 | * If we can seek there, just jump to it. |
74 | * If we can't seek, but we're trying to go to line number 1, |
75 | * use ch_beg_seek() to get as close as we can. |
76 | */ |
77 | pos = find_pos(linenum); |
78 | if (pos != -1 && ch_seek(pos) == 0) { |
79 | if (show_attn) |
80 | set_attnpos(pos); |
81 | jump_loc(pos, jump_sline); |
82 | } else if (linenum <= 1 && ch_beg_seek() == 0) { |
83 | jump_loc(ch_tell(), jump_sline); |
84 | error("Cannot seek to beginning of file", NULL((void *)0)); |
85 | } else { |
86 | parg.p_linenum = linenum; |
87 | error("Cannot seek to line number %n", &parg); |
88 | } |
89 | } |
90 | |
91 | /* |
92 | * Repaint the screen. |
93 | */ |
94 | void |
95 | repaint(void) |
96 | { |
97 | struct scrpos scrpos; |
98 | /* |
99 | * Start at the line currently at the top of the screen |
100 | * and redisplay the screen. |
101 | */ |
102 | get_scrpos(&scrpos); |
103 | pos_clear(); |
104 | jump_loc(scrpos.pos, scrpos.ln); |
105 | } |
106 | |
107 | /* |
108 | * Jump to a specified percentage into the file. |
109 | */ |
110 | void |
111 | jump_percent(int percent, long fraction) |
112 | { |
113 | off_t pos, len; |
114 | |
115 | /* |
116 | * Determine the position in the file |
117 | * (the specified percentage of the file's length). |
118 | */ |
119 | if ((len = ch_length()) == -1) { |
Although the value stored to 'len' is used in the enclosing expression, the value is never actually read from 'len' | |
120 | ierror("Determining length of file", NULL((void *)0)); |
121 | ch_end_seek(); |
122 | } |
123 | if ((len = ch_length()) == -1) { |
124 | error("Don't know length of file", NULL((void *)0)); |
125 | return; |
126 | } |
127 | pos = percent_pos(len, percent, fraction); |
128 | if (pos >= len) |
129 | pos = len-1; |
130 | |
131 | jump_line_loc(pos, jump_sline); |
132 | } |
133 | |
134 | /* |
135 | * Jump to a specified position in the file. |
136 | * Like jump_loc, but the position need not be |
137 | * the first character in a line. |
138 | */ |
139 | void |
140 | jump_line_loc(off_t pos, int sline) |
141 | { |
142 | int c; |
143 | |
144 | if (ch_seek(pos) == 0) { |
145 | /* |
146 | * Back up to the beginning of the line. |
147 | */ |
148 | while ((c = ch_back_get()) != '\n' && c != EOI(-1)) |
149 | ; |
150 | if (c == '\n') |
151 | (void) ch_forw_get(); |
152 | pos = ch_tell(); |
153 | } |
154 | if (show_attn) |
155 | set_attnpos(pos); |
156 | jump_loc(pos, sline); |
157 | } |
158 | |
159 | /* |
160 | * Jump to a specified position in the file. |
161 | * The position must be the first character in a line. |
162 | * Place the target line on a specified line on the screen. |
163 | */ |
164 | void |
165 | jump_loc(off_t pos, int sline) |
166 | { |
167 | int nline; |
168 | off_t tpos; |
169 | off_t bpos; |
170 | |
171 | /* |
172 | * Normalize sline. |
173 | */ |
174 | sline = adjsline(sline); |
175 | |
176 | if ((nline = onscreen(pos)) >= 0) { |
177 | /* |
178 | * The line is currently displayed. |
179 | * Just scroll there. |
180 | */ |
181 | nline -= sline; |
182 | if (nline > 0) |
183 | forw(nline, position(BOTTOM_PLUS_ONE(-2)), 1, 0, 0); |
184 | else |
185 | back(-nline, position(TOP(0)), 1, 0); |
186 | if (show_attn) |
187 | repaint_hilite(1); |
188 | return; |
189 | } |
190 | |
191 | /* |
192 | * Line is not on screen. |
193 | * Seek to the desired location. |
194 | */ |
195 | if (ch_seek(pos)) { |
196 | error("Cannot seek to that file position", NULL((void *)0)); |
197 | return; |
198 | } |
199 | |
200 | /* |
201 | * See if the desired line is before or after |
202 | * the currently displayed screen. |
203 | */ |
204 | tpos = position(TOP(0)); |
205 | bpos = position(BOTTOM_PLUS_ONE(-2)); |
206 | if (tpos == -1 || pos >= tpos) { |
207 | /* |
208 | * The desired line is after the current screen. |
209 | * Move back in the file far enough so that we can |
210 | * call forw() and put the desired line at the |
211 | * sline-th line on the screen. |
212 | */ |
213 | for (nline = 0; nline < sline; nline++) { |
214 | if (bpos != -1 && pos <= bpos) { |
215 | /* |
216 | * Surprise! The desired line is |
217 | * close enough to the current screen |
218 | * that we can just scroll there after all. |
219 | */ |
220 | forw(sc_height-sline+nline-1, bpos, 1, 0, 0); |
221 | if (show_attn) |
222 | repaint_hilite(1); |
223 | return; |
224 | } |
225 | pos = back_line(pos); |
226 | if (pos == -1) { |
227 | /* |
228 | * Oops. Ran into the beginning of the file. |
229 | * Exit the loop here and rely on forw() |
230 | * below to draw the required number of |
231 | * blank lines at the top of the screen. |
232 | */ |
233 | break; |
234 | } |
235 | } |
236 | lastmark(); |
237 | squished = 0; |
238 | screen_trashed = 0; |
239 | forw(sc_height-1, pos, 1, 0, sline-nline); |
240 | } else { |
241 | /* |
242 | * The desired line is before the current screen. |
243 | * Move forward in the file far enough so that we |
244 | * can call back() and put the desired line at the |
245 | * sline-th line on the screen. |
246 | */ |
247 | for (nline = sline; nline < sc_height - 1; nline++) { |
248 | pos = forw_line(pos); |
249 | if (pos == -1) { |
250 | /* |
251 | * Ran into end of file. |
252 | * This shouldn't normally happen, |
253 | * but may if there is some kind of read error. |
254 | */ |
255 | break; |
256 | } |
257 | if (pos >= tpos) { |
258 | /* |
259 | * Surprise! The desired line is |
260 | * close enough to the current screen |
261 | * that we can just scroll there after all. |
262 | */ |
263 | back(nline + 1, tpos, 1, 0); |
264 | if (show_attn) |
265 | repaint_hilite(1); |
266 | return; |
267 | } |
268 | } |
269 | lastmark(); |
270 | if (!top_scroll) |
271 | do_clear(); |
272 | else |
273 | home(); |
274 | screen_trashed = 0; |
275 | add_back_pos(pos); |
276 | back(sc_height-1, pos, 1, 0); |
277 | } |
278 | } |