ncurses 5.4
[ncurses.git] / form / frm_data.c
1 /****************************************************************************
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28
29 /****************************************************************************
30  *   Author:  Juergen Pfeifer, 1995,1997                                    *
31  ****************************************************************************/
32
33 #include "form.priv.h"
34
35 MODULE_ID("$Id: frm_data.c,v 1.10 2003/11/08 20:38:14 tom Exp $")
36
37 /*---------------------------------------------------------------------------
38 |   Facility      :  libnform  
39 |   Function      :  bool data_behind(const FORM *form)
40 |   
41 |   Description   :  Check for off-screen data behind. This is nearly trivial
42 |                    because the beginning of a field is fixed.
43 |
44 |   Return Values :  TRUE   - there are off-screen data behind
45 |                    FALSE  - there are no off-screen data behind
46 +--------------------------------------------------------------------------*/
47 NCURSES_EXPORT(bool)
48 data_behind (const FORM *form)
49 {
50   bool result = FALSE;
51
52   if (form && (form->status & _POSTED) && form->current)
53     {
54       FIELD *field;
55
56       field = form->current;
57       if (!Single_Line_Field(field))
58         {
59           result = (form->toprow==0) ? FALSE : TRUE;
60         }
61       else
62         {
63           result = (form->begincol==0) ? FALSE : TRUE;
64         }
65     }
66   return(result);
67 }
68
69 /*---------------------------------------------------------------------------
70 |   Facility      :  libnform  
71 |   Function      :  static char * After_Last_Non_Pad_Position(
72 |                                    char *buffer,
73 |                                    int len,
74 |                                    int pad)
75 |   
76 |   Description   :  Find the last position in the buffer that doesn't
77 |                    contain a padding character.
78 |
79 |   Return Values :  The pointer to this position 
80 +--------------------------------------------------------------------------*/
81 INLINE 
82 static char * After_Last_Non_Pad_Position(char *buffer, int len, int pad)
83 {
84   char *end = buffer + len;
85
86   assert(buffer && len>=0);
87   while ( (buffer < end) && (*(end-1)==pad) )
88     end--;
89
90   return end;
91 }
92
93 #define SMALL_BUFFER_SIZE (80)
94
95 /*---------------------------------------------------------------------------
96 |   Facility      :  libnform  
97 |   Function      :  bool data_ahead(const FORM *form)
98 |   
99 |   Description   :  Check for off-screen data ahead. This is more difficult
100 |                    because a dynamic field has a variable end. 
101 |
102 |   Return Values :  TRUE   - there are off-screen data ahead
103 |                    FALSE  - there are no off-screen data ahead
104 +--------------------------------------------------------------------------*/
105 NCURSES_EXPORT(bool)
106 data_ahead (const FORM *form)
107 {
108   bool result = FALSE;
109
110   if (form && (form->status & _POSTED) && form->current)
111     {
112       static char buffer[SMALL_BUFFER_SIZE + 1];
113       FIELD *field;
114       bool large_buffer;
115       bool cursor_moved = FALSE;
116       char *bp;
117       char *found_content;
118       int pos;
119
120       field = form->current;
121       assert(form->w);
122
123       large_buffer = (field->cols > SMALL_BUFFER_SIZE);
124       if (large_buffer)
125         bp = (char *)malloc((size_t)(field->cols) + 1);
126       else
127         bp = buffer;
128
129       assert(bp);
130       
131       if (Single_Line_Field(field))
132         {
133           int check_len;
134
135           pos = form->begincol + field->cols;
136           while (pos < field->dcols)
137             {
138               check_len = field->dcols - pos;
139               if ( check_len >= field->cols )
140                 check_len = field->cols;
141               cursor_moved = TRUE;
142               wmove(form->w,0,pos);
143               winnstr(form->w,bp,check_len);
144               found_content = 
145                 After_Last_Non_Pad_Position(bp,check_len,field->pad);
146               if (found_content==bp)
147                   pos += field->cols;             
148               else
149                 {
150                   result = TRUE;
151                   break;
152                 }
153             }
154         }
155       else
156         {
157           pos = form->toprow + field->rows;
158           while (pos < field->drows)
159             {
160               cursor_moved = TRUE;
161               wmove(form->w,pos,0);
162               pos++;
163               winnstr(form->w,bp,field->cols);
164               found_content = 
165                 After_Last_Non_Pad_Position(bp,field->cols,field->pad);
166               if (found_content!=bp)
167                 {
168                   result = TRUE;
169                   break;
170                 }
171             }
172         }
173
174       if (large_buffer)
175         free(bp);
176
177       if (cursor_moved)
178         wmove(form->w,form->currow,form->curcol);
179     }
180   return(result);
181 }
182
183 /* frm_data.c ends here */