Add example which uses the frame api through the library

1 files changed, 165 insertions, 0 deletions

diff --git a/examples/frameCompress.c b/examples/frameCompress.c
new file mode 100644
index 0000000..7b13579
--- /dev/null
+++ b/examples/frameCompress.c
@@ -0,0 +1,165 @@
+#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 = {
+	{ 5, 0, 0, 0, 0, { 0, 0 } },
+	0,
+	0,
+	{ 0, 0, 0, 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]);
+}