1 files changed, 88 insertions, 0 deletions
diff --git a/analyze_gz.c b/analyze_gz.c
new file mode 100644
index 0000000..1ea0d78
--- /dev/null
+++ b/analyze_gz.c
@@ -0,0 +1,88 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "hexdump_pretty.h"
+
+#include "gzip.h"
+
+int main(int argc, char *argv[]) {
+	if (argc == 1) {
+		fprintf(stderr, "Usage: %s <filename.gz>\n", argv[0]);
+		return 1;
+	}
+
+	FILE *f = fopen(argv[1], "rb");
+	size_t len;
+
+	struct member header;
+	uint8_t *extra_fields = NULL;
+	uint16_t crc16 = 0;
+	char *filename = NULL;
+	char *file_comment = NULL;
+
+	len = fread(&header, sizeof(header), 1, f);
+
+	if (len != 1) {
+		fprintf(stderr, "Unexpected end of header\n");
+		return 1;
+	}
+
+	write_chunk_s((uint8_t[2]) {header.id1, header.id2}, 2);
+	write_chunk_s(&header.cm, 1);
+	write_chunk_s(&header.flg, 1);
+	{
+		size_t s = sizeof(header.mtime);
+		uint8_t *buf = malloc(s);
+		memcpy(buf, &header.mtime, s);
+		write_chunk(buf, s);
+	}
+	write_chunk_s(&header.xfl, 1);
+	write_chunk_s(&header.os, 1);
+
+	if (header.flg & FEXTRA) {
+		uint16_t xlen;
+		len = fread(&xlen, sizeof(xlen), 1, f);
+		{
+			uint8_t *buf = malloc(len);
+			memcpy(buf, &xlen, len);
+			write_chunk(buf, len);
+		}
+		extra_fields = malloc(xlen);
+		len = fread(extra_fields, 1, xlen, f);
+		write_chunk(extra_fields, xlen);
+	}
+
+	if (header.flg & FNAME) {
+		size_t n;
+		len = getdelim(&filename, &n, '\0', f);
+		write_chunk((uint8_t*) filename, n);
+	}
+
+	if (header.flg & FCOMMENT) {
+		size_t n;
+		len = getdelim(&file_comment, &n, '\0', f);
+		write_chunk((uint8_t*) file_comment, n);
+	}
+
+	if (header.flg & FHCRC) {
+		len = fread(&crc16, sizeof(crc16), 1, f);
+		{
+			uint8_t *buf = malloc(len);
+			memcpy(buf, &crc16, len);
+			write_chunk(buf, len);
+		}
+	}
+
+// cleanup:
+	if (extra_fields) free(extra_fields);
+	if (filename) free(filename);
+	if (file_comment) free(file_comment);
+	flush_line();
+	cleanup_line();
+
+	printf("\n");
+
+
+}