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SwRI can revise these Terms at any time * without notice by updating this posting. * * Trademarks * * The SwRI logo is a trademark of SwRI in the United States and other countries. * */ #ident "@(#) read_header.c 1.30 05/08/19 SwRI" #include #if defined (__MINGW32__) || defined (__MSVCRT__) #include #else #include #endif #include #include #include "gen_defs.h" #include "ret_codes.h" #include "libbase_idfs.h" #include "libVIDF.h" /* for header format comparison */ /***************************************************************************** * * * IR_READ_HEADER SUBROUTINE * * * * DESCRIPTION * * This routine is called anytime a new header record needs to be read. * * If the header being read is the first header to be read, memory is * * allocated and pointers are set. If the header being read is not the * * first header record to be read, a check is made to see if the size of * * the header record has increased, and if so, memory is reallocated and * * pointers are reset. If the size hasn't increased, the pointers that * * need to be redefined based on the values read from the header are * * processed. If upon record retrieval, an EOF code is encountered or if a * * partial record is read, an internal flag is set so that the next time * * read_drec () or read_tensor_data () is called, another attempt is made * * to read from the header file. This additional attempt is made for * * real-time processing only. A partial record is considered a fatal error * * for playback processing. Since new header record formats had to be * * defined to incorporate multi-dimensional data into IDFS, it was decided * * to let this module make the decision as to which header record format * * module was to be invoked as opposed to having to change the modules * * which call this routine. * * * * INPUT VARIABLES * * void *data_ptr ptr to memory location for structure that * * holds returned data values (either * * idf_data or tensor_data) * * * * USAGE * * x = ir_read_header (data_ptr) * * * * NECESSARY SUBPROGRAMS * * sizeof () the size of the specified object in bytes * * lseek() moves the file pointer to a location * * within the file * * read() reads N bytes from the file associated * * with the file descriptor given * * malloc() allocates memory * * realloc() reallocates memory * * free () frees previously allocated memory * * ntohs () network to host short conversion * * ir_read_header_format_one() processes the header record according to * * the original IDFS header definition * * ir_read_header_format_two() processes the header record according to * * the single-value tensor header definition * * * * EXTERNAL VARIABLES * * struct general_info ginfo structure that holds information concern- * * ing the experiment that is being processed* * * * INTERNAL VARIABLES * * struct experiment_info *ex a pointer to the structure that holds * * specific experiment information * * struct ptr_rec *ptr a pointer to the structure which holds * * all pointers to the header and data for * * the experiment of interest * * size_t bytes the number of bytes to allocate * * size_t num_bytes_sshort number of bytes needed for a SDDAS_SHORT * * int num_bytes the no. of bytes requested from the file * * int ret_bytes the no. of bytes actually read by READ() * * SDDAS_SHORT header_size the size of the header record * * SDDAS_SHORT rval the value returned by the called routine * * SDDAS_CHAR larger_header flag that indicates if a larger header * * was read * * void *tmp_ptr pointer which holds address passed back by* * the call to the MALLOC routine * * * * SUBSYSTEM * * Display Level * * * *****************************************************************************/ SDDAS_SHORT ir_read_header (void *data_ptr) { extern struct general_info ginfo; struct experiment_info *ex; struct ptr_rec *ptr; size_t bytes, num_bytes_sshort; int num_bytes, ret_bytes; SDDAS_SHORT header_size, rval; SDDAS_CHAR larger_header; void *tmp_ptr; /***************************************************************************/ /* Determine the size of the header. */ /***************************************************************************/ ex = ginfo.expt; ptr = ex->info_ptr; larger_header = 0; num_bytes_sshort = sizeof (SDDAS_SHORT); num_bytes = num_bytes_sshort; ret_bytes = read (ex->fdh, (char *) &header_size, num_bytes); header_size = ntohs (header_size); /***************************************************************************/ /* Error conditions are the exception, not the rule, so only determine */ /* the exact error when necessary. */ /***************************************************************************/ if (ret_bytes != num_bytes) { /***************************************************************************/ /* A read error was encountered on the file. */ /***************************************************************************/ if (ret_bytes < 0) return (RHDR_READ_ERROR); /***************************************************************************/ /* If a non-real time file is being processed, an error was encountered. */ /* For real time, the record may not have been written to disk yet. */ /***************************************************************************/ else if (ret_bytes == 0) { ex->hrec_eof = 1; if (ex->requested_time.btime_sec >= 0) return (RHDR_READ_ERROR); else return (EOF_STATUS); } /***********************************************************************/ /* Back up the partial number of bytes read for future read attempts */ /* for real time files; non-real time files result in a read error. */ /***********************************************************************/ else { ex->hrec_eof = 1; lseek (ex->fdh, (off_t) (-1 * ret_bytes), 1); if (ex->requested_time.btime_sec >= 0) return (PARTIAL_READ); else return (EOF_STATUS); } } /***********************************************************************/ /* The header is a fill header (header not yet received on LAN by */ /* listener). Back up the bytes read to get the header size in */ /* anticipation of future read attempts. */ /***********************************************************************/ if (header_size == 0 || header_size == NO_MORE_DATA || header_size == NEXT_FILE) { ex->hrec_eof = 1; ret_bytes = num_bytes_sshort; lseek (ex->fdh, (off_t) (-1 * ret_bytes), 1); /*********************************************************************/ /* The listener has encountered an LOS or EOF while waiting on the */ /* redelivery of the header record in question. */ /*********************************************************************/ if (header_size == NO_MORE_DATA) return (LOS_STATUS); else if (header_size == NEXT_FILE) return (NEXT_FILE_STATUS); else if (ex->requested_time.btime_sec >= 0) return (FILL_HEADER); else return (EOF_STATUS); } /************************************************************************/ /* If space has been previously allocated, free old memory before new */ /* space is allocated. */ /************************************************************************/ if (ptr->h_size == -1) { bytes = header_size; if (ex->bmem.base_hdr != NO_MEMORY) { free (ex->bmem.base_hdr); ex->bmem.base_hdr = NO_MEMORY; if (ex->header_format == ORIGINAL_HEADER && ptr->base_idfs_info != NO_MEMORY) { free (ptr->base_idfs_info); ptr->base_idfs_info = NO_MEMORY; ptr->hdr_fmt1_ptr = NO_MEMORY; } else if (ex->header_format == TENSOR_SINGLE_HEADER && ptr->base_tensor_info != NO_MEMORY) { free (ptr->base_tensor_info); ptr->base_tensor_info = NO_MEMORY; ptr->hdr_fmt2_ptr = NO_MEMORY; } } if ((tmp_ptr = malloc (bytes)) == NO_MEMORY) return (RHDR_HDR_MALLOC); ex->bmem.base_hdr = tmp_ptr; ex->HEADER_MEM = (SDDAS_CHAR *) ex->bmem.base_hdr; larger_header = 1; } /*********************************************************************/ /* Reallocate the memory for the header information if the size of */ /* the header increased in size. */ /*********************************************************************/ else if (header_size > ptr->h_size) { bytes = header_size; if (ex->header_format == ORIGINAL_HEADER && ptr->base_idfs_info != NO_MEMORY) { free (ptr->base_idfs_info); ptr->base_idfs_info = NO_MEMORY; ptr->hdr_fmt1_ptr = NO_MEMORY; } else if (ex->header_format == TENSOR_SINGLE_HEADER && ptr->base_tensor_info != NO_MEMORY) { free (ptr->base_tensor_info); ptr->base_tensor_info = NO_MEMORY; ptr->hdr_fmt2_ptr = NO_MEMORY; } if ((tmp_ptr = realloc (ex->bmem.base_hdr, bytes)) == NO_MEMORY) return (RHDR_HDR_REALLOC); ex->bmem.base_hdr = tmp_ptr; ex->HEADER_MEM = (SDDAS_CHAR *) ex->bmem.base_hdr; larger_header = 1; } /********************************************************************/ /* Read in the new header information. */ /********************************************************************/ num_bytes = header_size - num_bytes_sshort; ret_bytes = read (ex->fdh, ex->HEADER_MEM + num_bytes_sshort, num_bytes); /***************************************************************************/ /* Error conditions are the exception, not the rule, so only determine */ /* the exact error when necessary. */ /***************************************************************************/ if (ret_bytes != num_bytes) { /***************************************************************************/ /* A read error was encountered on the file. */ /***************************************************************************/ if (ret_bytes < 0) return (RHDR_READ_ERROR); /***************************************************************************/ /* If a non-real time file is being processed, an error was encountered. */ /* For real time, the record may not have been written to disk yet. */ /* Back up the bytes read to get the header size in anticipation of */ /* future read attempts. */ /***************************************************************************/ else if (ret_bytes == 0) { ex->hrec_eof = 1; ret_bytes = num_bytes_sshort; lseek (ex->fdh, (off_t) (-1 * ret_bytes), 1); if (ex->requested_time.btime_sec >= 0) return (RHDR_READ_ERROR); else return (EOF_STATUS); } /***********************************************************************/ /* Back up the partial number of bytes read for future read attempts */ /* for real time files; non-real time files result in a read error. */ /* Don't forget the bytes read to get the header size. */ /***********************************************************************/ else { ex->hrec_eof = 1; num_bytes = ret_bytes + num_bytes_sshort; lseek (ex->fdh, (off_t) (-1 * num_bytes), 1); if (ex->requested_time.btime_sec >= 0) return (PARTIAL_READ); else return (EOF_STATUS); } } /***************************************************************************/ /* Determine which header record format is to be utilized. No need to */ /* check validity of format value since already done. */ /***************************************************************************/ ptr->h_size = header_size; if (ex->header_format == ORIGINAL_HEADER) rval = ir_read_header_format_one (larger_header, data_ptr); else rval = ir_read_header_format_two (larger_header, data_ptr); return (rval); }