dirfile2ascii(1) [debian man page]
dirfile2ascii(1) GETDATA dirfile2ascii(1) NAME
dirfile2ascii -- output dirfile database vectors as ASCII text SYNOPSIS
dirfile2ascii [ OPTION ]... DIRFILE [ [ -a | -A | -e | -E | -F | -g | -G | -o | -i | -u | -x | -X ] FIELD ]... DESCRIPTION
Fetches data from a dirfile(5) database specified by DIRFILE and writes it as ASCII to standard output. Any number of vector FIELDs may be specified. Each specified field is printed in a separate column. Mandatory arguments to long options are mandatory for short options too. -d, --delimeter=delim separate columns by delim. (Default: a single space.) -f, --first-frame=first_frame-last_frame read from frame first_frame to frame last_frame (inclusive). -f, --first-frame=first_frame:nframes equivalent to --first-frame=first_frame --num-frames=nframes. -f, --first-frame=first_frame If first_frame >= 0, start reading at frame first_frame. If first_frame is -1 and --num-frames=nframes is specified, read the last nframes frames. If --first-frame is not specified, reading starts at frame zero. -n, --num-frames=nframes read at most nframes frames. If not specified, or if nframes = 0, all frames to the end-of-field are read. -p, --precision=format use format to format output. format may contain any of the flag characters, a field width, and/or a precision as specified in printf(3). It may not contain a length modifier. -q, --quiet don't write diagnostic messages on standard error. (This is the default behaviour). -s, --skip=frame_skip if frame_skip > 0, output only one sample for every frame_skip frames. -v, --verbose write diagnostic messages on standard error. -z, --fill=STRING Fill columns which go past the end of their corresponding field with the string STRING. The default behaviour is to fill columns with floating-point conversions with NaN and columns with integer conversion with 0, which mirrors what occurs when an attempt is made to print data from before the start of a field. (Note: the default behaviour cannot be reproduced with this option, since STRING is applied to all columns, regardless of conversion type.) In addition to the above, each FIELD argument may be preceded by a short option, one of: -a, -A, -e, -E, -F, -g, -G, -i, -o, -u, -x, -X, indicating the conversion to be used. See printf(3) for the meaning of these conversion specifiers. The output flags, width, and preci- sion may be specified by using --precision. If no conversion specifier is given, %f is used. For conversion specifiers %a, %A, %e, %E, %f, %F, %g, %G, data is read from the dirfile as double precision floats. For conversion speci- fier %i, data is read as 64-bit signed integers. For conversion specifiers %o, %u, %x, %X, data is read as 64-bit unsigned integers. LIMITATIONS
No native support for printing complex data is provided. This may be worked around by using dirfile(5) representation suffixes. For exam- ple, the command $ dirfile2ascii DIRFILE FIELD.r FIELD.i will print the real and imaginary parts of the complex valued field FIELD in the first and second columns, respectively. SEE ALSO
dirfile(5), printf(3) Version 0.7.1 30 November 2010 dirfile2ascii(1)
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gd_getdata(3) GETDATA gd_getdata(3) NAME
gd_getdata -- retrieve data from a dirfile database SYNOPSIS
#include <getdata.h> size_t gd_getdata(DIRFILE *dirfile, const char *field_code, off_t first_frame, off_t first_sample, size_t num_frames, size_t num_samples, gd_type_t return_type, void *data_out); DESCRIPTION
The gd_getdata() function queries a dirfile(5) database specified by dirfile for the field field_code. It fetches num_frames frames plus num_samples samples from this field, starting first_sample samples past frame first_frame. The data is converted to the data type speci- fied by return_type, and stored in the user-supplied buffer data_out. The field_code may contain one of the representation suffixes listed in dirfile-format(5). If it does, gd_getdata() will compute the ap- propriate complex norm before returning the data. The dirfile argument must point to a valid DIRFILE object previously created by a call to gd_open(3). The argument data_out must point to a valid memory location of sufficient size to hold all data requested. The first sample returned will be first_frame * samples_per_frame + first_sample as measured from the start of the dirfile, where samples_per_frame is the number of samples per frame as returned by gd_spf(3). The number of samples fetched is, similarly, num_frames * samples_per_frame + num_samples. Although calling gd_getdata() using both samples and frames is possible, the function is typically called with either num_samples and first_sample, or num_frames and first_frames, equal to zero. The return_type argument should be one of the following symbols, which indicates the desired return type of the data: GD_UINT8 unsigned 8-bit integer GD_INT8 signed (two's complement) 8-bit integer GD_UINT16 unsigned 16-bit integer GD_INT16 signed (two's complement) 16-bit integer GD_UINT32 unsigned 32-bit integer GD_INT32 signed (two's complement) 32-bit integer GD_UINT64 unsigned 64-bit integer GD_INT64 signed (two's complement) 64-bit integer GD_FLOAT32 IEEE-754 standard 32-bit single precision floating point number GD_FLOAT64 IEEE-754 standard 64-bit double precision floating point number GD_COMPLEX64 C99-conformant 64-bit single precision complex number GD_COMPLEX128 C99-conformant 128-bit double precision complex number GD_NULL the null type: the database is queried as usual, but no data is returned. In this case, data_out is ignored and may be NULL. The return type of the data need not be the same as the type of the data stored in the database. Type conversion will be performed as nec- essary to return the requested type. If the field_code does not indicate a representation, but conversion from a complex value to a purely real one is required, only the real portion of the requested vector will be returned. RETURN VALUE
In all cases, gd_getdata() returns the number of samples (not bytes) successfully read from the database. If the end-of-field is encoun- tered before the requested number of samples have been read, a short count will result. The library does not consider this an error. Re- quests for data before the beginning-of-field marker, which may have been shifted from frame zero by the presence of a FRAMEOFFSET direc- tive, will result in the the data being padded at the front by NaN or zero depending on whether the return type is of floating point or in- tegral type. If an error has occurred, zero is returned and the dirfile error will be set to a non-zero value. Possible error values are: GD_E_ALLOC The library was unable to allocate memory. GD_E_BAD_CODE The field specified by field_code, or one of the fields it uses for input, was not found in the database. GD_E_BAD_DIRFILE An invalid dirfile was supplied. GD_E_BAD_FIELD_TYPE The supplied field_code referred to a CONST, CARRAY, or STRING field. The caller should use gd_get_constant(3), gd_get_carray(3), or gd_get_string(3) instead. GD_E_BAD_REPR The representation suffix specified in field_code, or in one of the field codes it uses for input, was invalid. GD_E_BAD_SCALAR A scalar field used in the definition of the field was not found, or was not of scalar type. GD_E_BAD_TYPE An invalid return_type was specified. GD_E_DIMENSION A scalar field was found where a vector field was expected. GD_E_INTERNAL_ERROR An internal error occurred in the library while trying to perform the task. This indicates a bug in the library. Please report the incident to the maintainer. GD_E_OPEN_LINFILE An error occurred while trying to read a LINTERP table from disk. GD_E_RAW_IO An error occurred while trying to open or read from a file on disk containing a raw field. GD_E_RECURSE_LEVEL Too many levels of recursion were encountered while trying to resolve field_code. This usually indicates a circular dependency in field specification in the dirfile. GD_E_UNKNOWN_ENCODING The encoding scheme of a RAW field could not be determined. This may also indicate that the binary file associated with the RAW field could not be found. GD_E_UNSUPPORTED Reading from dirfiles with the encoding scheme of the specified dirfile is not supported by the library. See dirfile-encoding(5) for details on dirfile encoding schemes. The dirfile error may be retrieved by calling gd_error(3). A descriptive error string for the last error encountered can be obtained from a call to gd_error_string(3). LIMITATIONS
The PHASE field type is poorly defined, since a forward-shifted PHASE field will always encounter the end-of-field marker before its input field does. This has ramifications when using gd_getdata() with streaming data. The Dirfile Standards make tacit admission to this prob- lem by indicating the results of reading a PHASE field beyond the beginning- or end-of-field is "implementation dependent" (see dirfile- format(5)). As with any other field, gd_getdata() will return a short count whenever a read from a PHASE field encounters the end-of-field marker. Backward-shifted PHASE fields do not suffer from this problem, since gd_getdata() pads reads past the beginning-of-field marker with NaN or zero as appropriate. Database creators who wish to use the PHASE field type with streaming data are encouraged to work around this limita- tion by only using backward-shifted PHASE fields, by writing RAW data at the maximal time lag, and then back-shifting all data which should have been written earlier. Another possible work-around is to write systematically less data to the first RAW field in proportion to the maximal forward phase shift. This method will work with applications which respect the database size reported by gd_nframes(3) resulting in these applications effectively ignoring all frames past the frame containing the maximally forward-shifted PHASE field's end-of-field marker. SEE ALSO
dirfile(5), dirfile-encoding(5), gd_open(3), gd_get_constant(3), gd_error(3), gd_error_string(3), gd_nframes(3), gd_spf(3), gd_get_string(3), gd_putdata(3) Version 0.7.0 3 November 2010 gd_getdata(3)