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CV(1)

NAME

cv - convert binary data files between representation formats

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SYNOPSIS

cv in_pat out_pat [[infile] outfile]

DESCRIPTION

cv converts a stream of binary numbers from one representation (format) to another, reading from infile and writing the converted result to outfile. Each format is described by a short pattern (no embedded blanks) drawn from the choices [h|n][s|u][c|s|i|l|d|8|16|32|64]:

  • h or n: Host-specific (h) or network-independent (n) byte order. Host format uses the native number representation and byte ordering of the machine running cv. Network format is big-endian, two’s complement; network doubles are 64-bit IEEE 754 in big-endian order. When omitted, network format is assumed.

  • s or u: Signed (s) or unsigned (u) integer. This flag has no effect on the double-precision format. When omitted, signed format is assumed.

  • c, s, i, l, d: C language types char, short, int, long, and double, sized as on the host processor.

  • 8, 16, 32, 64: Explicit bit sizes, typically paired with n to specify exact data sizes regardless of host word length.

For example, hui is a host unsigned int and nl is a network (signed) long. cv refuses to send binary output to a terminal.

OPTIONS

in_pat

Format pattern of the input data. An empty string ("") defaults to huc (host unsigned char).

out_pat

Format pattern of the output data. An empty string ("") defaults to nuc (network unsigned char).

infile

File to read input from. When both infile and outfile are given, this is the first filename; with a single filename it is the input and output goes to standard output. If omitted entirely, standard input is used.

outfile

File to write the converted data to. Present only when two filenames are supplied; otherwise output goes to standard output.

EXAMPLES

Example 1. Convert host signed shorts to network 32-bit integers
cv hss n32 data.short data.net

Reads the binary file data.short of machine-specific signed shorts and writes network-independent 32-bit integers to data.net, producing a portable file that can be read identically on any platform.

Example 2. Repack network doubles as host doubles in a pipeline
cat data.nd | cv nd hd > data.hd

Reads network-independent double-precision floats from standard input and emits host-native doubles on standard output, the typical first step before feeding the values to a program that expects local byte order.

SEE ALSO

brlcad(1), dpix-pix(1), pix-bw(1), bw-pix(1)

  1. J. Muuss, Workstations, Networking, Distributed Graphics, and Parallel Processing in Computer Graphics Techniques: Theory and Practice, edited by D. F. Rogers, R. A. Earnshaw, Springer-Verlag, 1990

AUTHOR

BRL-CAD Team

This software is Copyright (c) 1991-2026 by the United States Government as represented by U.S. Army Research Laboratory.

BUG REPORTS

Reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org