GRASS GIS 7 Programmer's Manual  7.7.svn(2018)-r73675
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xabs.c
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1 
2 #include <math.h>
3 
4 #include <grass/gis.h>
5 #include <grass/raster.h>
6 #include <grass/calc.h>
7 
8 /**********************************************************************
9 abs(x)
10 
11  absolute value. if x is negative returns -x
12 **********************************************************************/
13 
14 int f_abs(int argc, const int *argt, void **args)
15 {
16  int i;
17 
18  if (argc < 1)
19  return E_ARG_LO;
20  if (argc > 1)
21  return E_ARG_HI;
22 
23  if (argt[0] != argt[1])
24  return E_RES_TYPE;
25 
26  switch (argt[1]) {
27  case CELL_TYPE:
28  {
29  CELL *res = args[0];
30  CELL *arg1 = args[1];
31 
32  for (i = 0; i < columns; i++)
33  if (IS_NULL_C(&arg1[i]))
34  SET_NULL_C(&res[i]);
35  else
36  res[i] = arg1[i] < 0 ? -arg1[i]
37  : arg1[i];
38  return 0;
39  }
40  case FCELL_TYPE:
41  {
42  FCELL *res = args[0];
43  FCELL *arg1 = args[1];
44 
45  for (i = 0; i < columns; i++)
46  if (IS_NULL_F(&arg1[i]))
47  SET_NULL_F(&res[i]);
48  else
49  res[i] = (FCELL) fabs(arg1[i]);
50  return 0;
51  }
52  case DCELL_TYPE:
53  {
54  DCELL *res = args[0];
55  DCELL *arg1 = args[1];
56 
57  for (i = 0; i < columns; i++)
58  if (IS_NULL_D(&arg1[i]))
59  SET_NULL_D(&res[i]);
60  else
61  res[i] = fabs(arg1[i]);
62  return 0;
63  }
64  default:
65  return E_INV_TYPE;
66  }
67 }
#define CELL_TYPE
Definition: raster.h:11
#define SET_NULL_C(x)
Definition: calc.h:32
double DCELL
Definition: gis.h:581
#define IS_NULL_F(x)
Definition: calc.h:29
#define IS_NULL_C(x)
Definition: calc.h:28
Definition: calc.h:13
int columns
Definition: calc.c:12
#define DCELL_TYPE
Definition: raster.h:13
Definition: calc.h:12
float FCELL
Definition: gis.h:582
#define IS_NULL_D(x)
Definition: calc.h:30
int CELL
Definition: gis.h:580
#define FCELL_TYPE
Definition: raster.h:12
#define SET_NULL_F(x)
Definition: calc.h:33
#define SET_NULL_D(x)
Definition: calc.h:34
int f_abs(int argc, const int *argt, void **args)
Definition: xabs.c:14