00001 // vil_nitf2: Written by Harry Voorhees (hlv@) and Rob Radtke (rob@) of 00002 // Stellar Science Ltd. Co. (stellarscience.com) for 00003 // Air Force Research Laboratory, 2005. 00004 00005 #ifndef VIL_NITF2_SCALAR_FIELD_H 00006 #define VIL_NITF2_SCALAR_FIELD_H 00007 00008 #include "vil_nitf2_field.h" 00009 00010 class vil_nitf2_field_definition; 00011 class vil_nitf2_tagged_record_sequence; 00012 00013 // An abstract class that represents a scalar field, i.e., one that 00014 // is not within a repeat loop. Subclasses store the type-specific 00015 // value. 00016 00017 class vil_nitf2_scalar_field : public vil_nitf2_field 00018 { 00019 public: 00020 vil_nitf2_scalar_field(vil_nitf2_field_definition* definition) 00021 : vil_nitf2_field(definition) {} 00022 00023 virtual ~vil_nitf2_scalar_field() {} 00024 00025 virtual int num_dimensions() const { return 0; } 00026 00027 // Sets output argument to the value of field. Subclasses overload the 00028 // appropriate method to set out parameter and return true. These methods 00029 // are defined here for the convenience of my callers, so they don't 00030 // have to downcast to the specific field type. 00031 #if VXL_HAS_INT_64 00032 virtual bool value(vil_nitf2_long&) const { return false; } 00033 #endif 00034 virtual bool value(int&) const { return false; } 00035 virtual bool value(double&) const { return false; } 00036 virtual bool value(char&) const { return false; } 00037 virtual bool value(void*&) const { return false; } 00038 virtual bool value(vcl_string&) const { return false; } 00039 virtual bool value(vil_nitf2_location*&) const { return false; } 00040 virtual bool value(vil_nitf2_date_time&) const { return false; } 00041 virtual bool value(vil_nitf2_tagged_record_sequence&) const { return false; } 00042 00043 // Attempts to read a scalar field from input stream, using specified 00044 // definition. Returns field if successfully created. May set arg 00045 // error to true even if field is returned; for example, if it's a 00046 // required (non-blank) field that is all blank. If variable_width 00047 // is non-negative, it overrides the formatter's field width. 00048 static vil_nitf2_scalar_field* read(vil_nitf2_istream& input, 00049 vil_nitf2_field_definition* definition, 00050 int variable_width = -1, 00051 bool* error = 0); 00052 00053 virtual field_tree* get_tree() const; 00054 00055 // Write to NITF stream. Arg variable_width, if non-negative, overrides 00056 // formatter's field_width. 00057 bool write(vil_nitf2_ostream& output, int variable_width = -1) const; 00058 }; 00059 00060 #endif // VIL_NITF2_SCALAR_FIELD_H
1.7.5.1