e90f5a17ec4d54d929739040e8db52cba97b5d2f
[ncurses.git] / form / frm_data.c
1 /****************************************************************************
2  * Copyright (c) 1998 Free Software Foundation, Inc.                        *
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28
29 /****************************************************************************
30  *   Author: Juergen Pfeifer <juergen.pfeifer@gmx.net> 1995,1997            *
31  ****************************************************************************/
32
33 #include "form.priv.h"
34
35 MODULE_ID("$Id: frm_data.c,v 1.6 1999/05/16 17:20:29 juergen 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 |                    becose the begin 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 bool data_behind(const FORM *form)
48 {
49   bool result = FALSE;
50
51   if (form && (form->status & _POSTED) && form->current)
52     {
53       FIELD *field;
54
55       field = form->current;
56       if (!Single_Line_Field(field))
57         {
58           result = (form->toprow==0) ? FALSE : TRUE;
59         }
60       else
61         {
62           result = (form->begincol==0) ? FALSE : TRUE;
63         }
64     }
65   return(result);
66 }
67
68 /*---------------------------------------------------------------------------
69 |   Facility      :  libnform  
70 |   Function      :  static char * After_Last_Non_Pad_Position(
71 |                                    char *buffer,
72 |                                    int len,
73 |                                    int pad)
74 |   
75 |   Description   :  Find the last position in the buffer that doesn't
76 |                    contain a padding character.
77 |
78 |   Return Values :  The pointer to this position 
79 +--------------------------------------------------------------------------*/
80 INLINE 
81 static char * After_Last_Non_Pad_Position(char *buffer, int len, int pad)
82 {
83   char *end = buffer + len;
84
85   assert(buffer && len>=0);
86   while ( (buffer < end) && (*(end-1)==pad) )
87     end--;
88
89   return end;
90 }
91
92 #define SMALL_BUFFER_SIZE (80)
93
94 /*---------------------------------------------------------------------------
95 |   Facility      :  libnform  
96 |   Function      :  bool data_ahead(const FORM *form)
97 |   
98 |   Description   :  Check for off-screen data ahead. This is more difficult
99 |                    because a dynamic field has a variable end. 
100 |
101 |   Return Values :  TRUE   - there are off-screen data ahead
102 |                    FALSE  - there are no off-screen data ahead
103 +--------------------------------------------------------------------------*/
104 bool data_ahead(const FORM *form)
105 {
106   bool result = FALSE;
107
108   if (form && (form->status & _POSTED) && form->current)
109     {
110       static char buffer[SMALL_BUFFER_SIZE + 1];
111       FIELD *field;
112       bool large_buffer;
113       bool cursor_moved = FALSE;
114       char *bp;
115       char *found_content;
116       int pos;
117
118       field = form->current;
119       assert(form->w);
120
121       large_buffer = (field->cols > SMALL_BUFFER_SIZE);
122       if (large_buffer)
123         bp = (char *)malloc((size_t)(field->cols) + 1);
124       else
125         bp = buffer;
126
127       assert(bp);
128       
129       if (Single_Line_Field(field))
130         {
131           int check_len;
132
133           pos = form->begincol + field->cols;
134           while (pos < field->dcols)
135             {
136               check_len = field->dcols - pos;
137               if ( check_len >= field->cols )
138                 check_len = field->cols;
139               cursor_moved = TRUE;
140               wmove(form->w,0,pos);
141               winnstr(form->w,bp,check_len);
142               found_content = 
143                 After_Last_Non_Pad_Position(bp,check_len,field->pad);
144               if (found_content==bp)
145                   pos += field->cols;             
146               else
147                 {
148                   result = TRUE;
149                   break;
150                 }
151             }
152         }
153       else
154         {
155           pos = form->toprow + field->rows;
156           while (pos < field->drows)
157             {
158               cursor_moved = TRUE;
159               wmove(form->w,pos,0);
160               pos++;
161               winnstr(form->w,bp,field->cols);
162               found_content = 
163                 After_Last_Non_Pad_Position(bp,field->cols,field->pad);
164               if (found_content!=bp)
165                 {
166                   result = TRUE;
167                   break;
168                 }
169             }
170         }
171
172       if (large_buffer)
173         free(bp);
174
175       if (cursor_moved)
176         wmove(form->w,form->currow,form->curcol);
177     }
178   return(result);
179 }
180
181 /* frm_data.c ends here */