1fd794156e207961f2cd48a2396ba7120cfad03c
[ncurses.git] / form / frm_data.c
1 /*-----------------------------------------------------------------------------+
2 |           The ncurses form library is  Copyright (C) 1995-1997               |
3 |             by Juergen Pfeifer <Juergen.Pfeifer@T-Online.de>                 |
4 |                          All Rights Reserved.                                |
5 |                                                                              |
6 | Permission to use, copy, modify, and distribute this software and its        |
7 | documentation for any purpose and without fee is hereby granted, provided    |
8 | that the above copyright notice appear in all copies and that both that      |
9 | copyright notice and this permission notice appear in supporting             |
10 | documentation, and that the name of the above listed copyright holder(s) not |
11 | be used in advertising or publicity pertaining to distribution of the        |
12 | software without specific, written prior permission.                         | 
13 |                                                                              |
14 | THE ABOVE LISTED COPYRIGHT HOLDER(S) DISCLAIM ALL WARRANTIES WITH REGARD TO  |
15 | THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FIT-  |
16 | NESS, IN NO EVENT SHALL THE ABOVE LISTED COPYRIGHT HOLDER(S) BE LIABLE FOR   |
17 | ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RE- |
18 | SULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, |
19 | NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH    |
20 | THE USE OR PERFORMANCE OF THIS SOFTWARE.                                     |
21 +-----------------------------------------------------------------------------*/
22
23 #include "form.priv.h"
24
25 MODULE_ID("$Id: frm_data.c,v 1.3 1997/05/01 16:47:54 juergen Exp $")
26
27 /*---------------------------------------------------------------------------
28 |   Facility      :  libnform  
29 |   Function      :  bool data_behind(const FORM *form)
30 |   
31 |   Description   :  Check for off-screen data behind. This is nearly trivial
32 |                    becose the begin of a field is fixed.
33 |
34 |   Return Values :  TRUE   - there are off-screen data behind
35 |                    FALSE  - there are no off-screen data behind
36 +--------------------------------------------------------------------------*/
37 bool data_behind(const FORM *form)
38 {
39   bool result = FALSE;
40
41   if (form && (form->status & _POSTED) && form->current)
42     {
43       FIELD *field;
44
45       field = form->current;
46       if (!Single_Line_Field(field))
47         {
48           result = (form->toprow==0) ? FALSE : TRUE;
49         }
50       else
51         {
52           result = (form->begincol==0) ? FALSE : TRUE;
53         }
54     }
55   return(result);
56 }
57
58 /*---------------------------------------------------------------------------
59 |   Facility      :  libnform  
60 |   Function      :  static char * After_Last_Non_Pad_Position(
61 |                                    char *buffer,
62 |                                    int len,
63 |                                    int pad)
64 |   
65 |   Description   :  Find the last position in the buffer that doesn't
66 |                    contain a padding character.
67 |
68 |   Return Values :  The pointer to this position 
69 +--------------------------------------------------------------------------*/
70 INLINE 
71 static char * After_Last_Non_Pad_Position(char *buffer, int len, int pad)
72 {
73   char *end = buffer + len;
74
75   assert(buffer && len>=0);
76   while ( (buffer < end) && (*(end-1)==pad) )
77     end--;
78
79   return end;
80 }
81
82 #define SMALL_BUFFER_SIZE (80)
83
84 /*---------------------------------------------------------------------------
85 |   Facility      :  libnform  
86 |   Function      :  bool data_ahead(const FORM *form)
87 |   
88 |   Description   :  Check for off-screen data ahead. This is more difficult
89 |                    because a dynamic field has a variable end. 
90 |
91 |   Return Values :  TRUE   - there are off-screen data ahead
92 |                    FALSE  - there are no off-screen data ahead
93 +--------------------------------------------------------------------------*/
94 bool data_ahead(const FORM *form)
95 {
96   bool result = FALSE;
97
98   if (form && (form->status & _POSTED) && form->current)
99     {
100       static char buffer[SMALL_BUFFER_SIZE + 1];
101       FIELD *field;
102       bool large_buffer;
103       bool cursor_moved = FALSE;
104       char *bp;
105       char *found_content;
106       int pos;
107
108       field = form->current;
109       assert(form->w);
110
111       large_buffer = (field->cols > SMALL_BUFFER_SIZE);
112       if (large_buffer)
113         bp = (char *)malloc((size_t)(field->cols) + 1);
114       else
115         bp = buffer;
116
117       assert(bp);
118       
119       if (Single_Line_Field(field))
120         {
121           int check_len;
122
123           pos = form->begincol + field->cols;
124           while (pos < field->dcols)
125             {
126               check_len = field->dcols - pos;
127               if ( check_len >= field->cols )
128                 check_len = field->cols;
129               cursor_moved = TRUE;
130               wmove(form->w,0,pos);
131               winnstr(form->w,bp,check_len);
132               found_content = 
133                 After_Last_Non_Pad_Position(bp,check_len,field->pad);
134               if (found_content==bp)
135                   pos += field->cols;             
136               else
137                 {
138                   result = TRUE;
139                   break;
140                 }
141             }
142         }
143       else
144         {
145           pos = form->toprow + field->rows;
146           while (pos < field->drows)
147             {
148               cursor_moved = TRUE;
149               wmove(form->w,pos,0);
150               pos++;
151               winnstr(form->w,bp,field->cols);
152               found_content = 
153                 After_Last_Non_Pad_Position(bp,field->cols,field->pad);
154               if (found_content!=bp)
155                 {
156                   result = TRUE;
157                   break;
158                 }
159             }
160         }
161
162       if (large_buffer)
163         free(bp);
164
165       if (cursor_moved)
166         wmove(form->w,form->currow,form->curcol);
167     }
168   return(result);
169 }
170
171 /* frm_data.c ends here */