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// LZ4frame API example : compress a file
// Based on sample code from Zbigniew Jędrzejewski-Szmek
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <lz4frame.h>
#define BUF_SIZE (16*1024)
#define LZ4_HEADER_SIZE 19
#define LZ4_FOOTER_SIZE 4
static const LZ4F_preferences_t lz4_preferences = {
{ LZ4F_max256KB, LZ4F_blockLinked, LZ4F_noContentChecksum, LZ4F_frame, 0, { 0, 0 } },
0, /* compression level */
0, /* autoflush */
{ 0, 0, 0, 0 }, /* reserved, must be set to 0 */
};
static int compress_file(FILE *in, FILE *out, size_t *size_in, size_t *size_out) {
LZ4F_errorCode_t r;
LZ4F_compressionContext_t ctx;
char *src, *buf = NULL;
size_t size, n, k, count_in = 0, count_out, offset = 0, frame_size;
r = LZ4F_createCompressionContext(&ctx, LZ4F_VERSION);
if (LZ4F_isError(r)) {
printf("Failed to create context: error %zu", r);
return 1;
}
r = 1;
src = malloc(BUF_SIZE);
if (!src) {
printf("Not enough memory");
goto cleanup;
}
frame_size = LZ4F_compressBound(BUF_SIZE, &lz4_preferences);
size = frame_size + LZ4_HEADER_SIZE + LZ4_FOOTER_SIZE;
buf = malloc(size);
if (!buf) {
printf("Not enough memory");
goto cleanup;
}
n = offset = count_out = LZ4F_compressBegin(ctx, buf, size, &lz4_preferences);
if (LZ4F_isError(n)) {
printf("Failed to start compression: error %zu", n);
goto cleanup;
}
printf("Buffer size is %zu bytes, header size %zu bytes\n", size, n);
for (;;) {
k = fread(src, 1, BUF_SIZE, in);
if (k == 0)
break;
count_in += k;
n = LZ4F_compressUpdate(ctx, buf + offset, size - offset, src, k, NULL);
if (LZ4F_isError(n)) {
printf("Compression failed: error %zu", n);
goto cleanup;
}
offset += n;
count_out += n;
if (size - offset < frame_size + LZ4_FOOTER_SIZE) {
printf("Writing %zu bytes\n", offset);
k = fwrite(buf, 1, offset, out);
if (k < offset) {
if (ferror(out))
printf("Write failed");
else
printf("Short write");
goto cleanup;
}
offset = 0;
}
}
n = LZ4F_compressEnd(ctx, buf + offset, size - offset, NULL);
if (LZ4F_isError(n)) {
printf("Failed to end compression: error %zu", n);
goto cleanup;
}
offset += n;
count_out += n;
printf("Writing %zu bytes\n", offset);
k = fwrite(buf, 1, offset, out);
if (k < offset) {
if (ferror(out))
printf("Write failed");
else
printf("Short write");
goto cleanup;
}
*size_in = count_in;
*size_out = count_out;
r = 0;
cleanup:
if (ctx)
LZ4F_freeCompressionContext(ctx);
free(src);
free(buf);
return r;
}
static int compress(const char *input, const char *output) {
char *tmp = NULL;
FILE *in = NULL, *out = NULL;
size_t size_in = 0, size_out = 0;
int r = 1;
if (!output) {
size_t len = strlen(input);
output = tmp = malloc(len + 5);
if (!tmp) {
printf("Not enough memory");
return 1;
}
strcpy(tmp, input);
strcpy(tmp + len, ".lz4");
}
in = fopen(input, "rb");
if (!in) {
fprintf(stderr, "Failed to open input file %s: %s\n", input, strerror(errno));
goto cleanup;
}
out = fopen(output, "wb");
if (!out) {
fprintf(stderr, "Failed to open output file %s: %s\n", output, strerror(errno));
goto cleanup;
}
r = compress_file(in, out, &size_in, &size_out);
if (r == 0)
printf("%s: %zu → %zu bytes, %.1f%%\n",
input, size_in, size_out,
(double)size_out / size_in * 100);
cleanup:
if (in)
fclose(in);
if (out)
fclose(out);
free(tmp);
return r;
}
int main(int argc, char **argv) {
if (argc < 2 || argc > 3) {
fprintf(stderr, "Syntax: %s <input> <output>\n", argv[0]);
return EXIT_FAILURE;
}
return compress(argv[1], argv[2]);
}
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