blob: 683621add410b16308bf5377e482dc093c7ea454 [file] [log] [blame]
// Copyright 2018 The Wuffs Authors.
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
//> or the MIT license
// <LICENSE-MIT or>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// SPDX-License-Identifier: Apache-2.0 OR MIT
// ----------------
crc32 prints the CRC-32 checksum (using the IEEE polynomial) of stdin. It is
similar to the standard /usr/bin/crc32 program, except that this example
program only reads from stdin.
To run:
$CXX && ./a.out < ../../; rm -f a.out
for a C++ compiler $CXX, such as clang++ or g++.
#if defined(__cplusplus) && (__cplusplus < 201103L)
#error "This C++ program requires -std=c++11 or later"
#include <errno.h>
#include <inttypes.h>
#include <stdio.h>
// Wuffs ships as a "single file C library" or "header file library" as per
// To use that single file as a "foo.c"-like implementation, instead of a
// "foo.h"-like header, #define WUFFS_IMPLEMENTATION before #include'ing or
// compiling it.
// Defining the WUFFS_CONFIG__STATIC_FUNCTIONS macro is optional, but when
// combined with WUFFS_IMPLEMENTATION, it demonstrates making all of Wuffs'
// functions have static storage.
// This can help the compiler ignore or discard unused code, which can produce
// faster compiles and smaller binaries. Other motivations are discussed in the
// Defining the WUFFS_CONFIG__MODULE* macros are optional, but it lets users of
// release/c/etc.c choose which parts of Wuffs to build. That file contains the
// entire Wuffs standard library, implementing a variety of codecs and file
// formats. Without this macro definition, an optimizing compiler or linker may
// very well discard Wuffs code for unused codecs, but listing the Wuffs
// modules we use makes that process explicit. Preprocessing means that such
// code simply isn't compiled.
// If building this program in an environment that doesn't easily accommodate
// relative includes, you can use the script/inline-c-relative-includes.go
// program to generate a stand-alone C++ file.
#include "../../release/c/wuffs-unsupported-snapshot.c"
#define SRC_BUFFER_ARRAY_SIZE (32 * 1024)
uint8_t g_src_buffer_array[SRC_BUFFER_ARRAY_SIZE];
int //
main(int argc, char** argv) {
wuffs_crc32__ieee_hasher h;
wuffs_base__status status = h.initialize(sizeof h, WUFFS_VERSION, 0);
if (!status.is_ok()) {
fprintf(stderr, "%s\n", status.message());
return 1;
while (true) {
size_t n = fread(g_src_buffer_array, sizeof(uint8_t), SRC_BUFFER_ARRAY_SIZE,
uint32_t checksum =
h.update_u32(wuffs_base__make_slice_u8(g_src_buffer_array, n));
if (feof(stdin)) {
printf("%08" PRIx32 "\n", checksum);
return 0;
} else if (ferror(stdin)) {
fprintf(stderr, "read error\n");
return 1;