retdat

RetDat -- retrieve one sample from the ADB

BOOL retdat(buffer,offset,sample,sample_num)

ADB *buffer ;

unsigned short offset, sample_num ;

unsigned char *sample ;

PURPOSE

retdat copies one sample from the data_set into the area pointed to by "sample". Samples are numbered starting at 0. The directory entry located at "offset" bytes from the beginning of the ADB determines the location of the data_set and the size of the sample.

INPUTS

buffer

ADB - aircraft data block

offset

offset in bytes to directory entry

sample_num

number of desired sample

sample

location to which to copy the data

OUTPUTS

true if the sample is copied, false otherwise.

PARACODE

BOOL retdat(buffer,offset,data_element,data_set_index) find the specified directory entry if the directory entry element size = OVERFLOW then return NO if the data_set_index * element_size >= byte_count then return NO bytes_to_transfer = entry element_size data_element_address = start_of_adb + entry_data_offset + entry_element_size * data_set_index while there are still bytes_to_transfer do transfer the next data_element return YES

CODE

/* FILE: RETDAT.C */ #include #include "air.h" BOOLE retdat(buffer,offset,data_element,data_set_index) ADB *buffer ; unsigned short offset ; unsigned char *data_element ; unsigned short data_set_index ; { DIR_ENTRY *entry ; unsigned short bytes_to_transfer ; unsigned char *adb_data_element, *char_buffer ; char_buffer = (unsigned char *)buffer ; entry = (DIR_ENTRY *)(char_buffer + offset) ; if (entry->element_size == OVERFLOW) return(NO) ; if ((data_set_index * entry->element_size) >= entry->byte_count) return(NO) ; bytes_to_transfer = entry->element_size ; adb_data_element = char_buffer + entry->data_offset + entry->element_size * data_set_index ; while (bytes_to_transfer-- > 0) *data_element++ = *adb_data_element++ ; return(YES) ; }