unzip applet by Laurence Anderson

----------------------------------------------------------------------

1 files changed, 110 insertions, 0 deletions

diff --git a/archival/libunarchive/get_header_zip.c b/archival/libunarchive/get_header_zip.c
new file mode 100644
index 0000000..84f2a54
--- /dev/null
+++ b/archival/libunarchive/get_header_zip.c
@@ -0,0 +1,110 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * get_header_zip for busybox
+ *
+ * Copyright (C) 2001 by Laurence Anderson
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "unarchive.h"
+#include "libbb.h"
+
+#define ZIP_FILEHEADER_MAGIC 0x04034b50
+#define ZIP_CDS_MAGIC 0x02014b50
+#define ZIP_CDS_END_MAGIC 0x06054b50
+#define ZIP_DD_MAGIC 0x8074b50
+
+file_header_t *get_header_zip(FILE *zip_stream)
+{
+	struct {
+		short version __attribute__ ((packed));
+		short flags __attribute__ ((packed));
+		short method __attribute__ ((packed));
+		short modtime __attribute__ ((packed));
+		short moddate __attribute__ ((packed));
+		int crc32 __attribute__ ((packed));
+		int cmpsize __attribute__ ((packed));
+		int ucmpsize __attribute__ ((packed));
+		short filename_len __attribute__ ((packed));
+		short extra_len __attribute__ ((packed));
+	} zip_header;
+	file_header_t *zip_entry = NULL;
+	int magic;
+	static int dd_ahead = 0; // If this is true, the we didn't know how long the last extraced file was
+
+	fread (&magic, 4, 1, zip_stream);
+	archive_offset += 4;
+
+	if (feof(zip_stream)) return(NULL);
+checkmagic:
+	switch (magic) {
+		case ZIP_FILEHEADER_MAGIC:
+			zip_entry = xcalloc(1, sizeof(file_header_t));
+			fread (&zip_header, sizeof(zip_header), 1, zip_stream);
+			archive_offset += sizeof(zip_header);
+			if (!(zip_header.method == 8 || zip_header.method == 0)) { printf("Unsupported compression method %d\n", zip_header.method); return(NULL); }
+			zip_entry->name = calloc(zip_header.filename_len + 1, sizeof(char));
+			fread (zip_entry->name, sizeof(char), zip_header.filename_len, zip_stream);
+			archive_offset += zip_header.filename_len;
+			seek_sub_file(zip_stream, zip_header.extra_len);
+			zip_entry->size = zip_header.cmpsize;
+			if (zip_header.method == 8) zip_entry->extract_func = &inflate;
+			zip_entry->mode = S_IFREG | 0777;
+			// Time/Date?
+			if (*(zip_entry->name + strlen(zip_entry->name) - 1) == '/') { // Files that end in a / are directories
+				zip_entry->mode ^= S_IFREG;
+				zip_entry->mode |= S_IFDIR;
+				*(zip_entry->name + strlen(zip_entry->name) - 1) = '\0'; // Remove trailing / so unarchive doesn't get confused
+			}
+			//printf("cmpsize: %d, ucmpsize: %d, method: %d\n", zip_header.cmpsize, zip_header.ucmpsize, zip_header.method);
+			if (zip_header.flags & 0x8) { // crc32, and sizes are in the data description _after_ the file
+				if (zip_header.cmpsize == 0) dd_ahead = 1; // As we don't know how long this file it is difficult to skip! but it is compressed, so normally its ok
+				if (zip_header.ucmpsize != 0) dd_ahead = 2; // Humm... we would otherwise skip this twice - not good!
+			}
+			break;
+		case ZIP_CDS_MAGIC: /* FALLTHRU */
+		case ZIP_CDS_END_MAGIC:
+			return(NULL);
+			break;
+		case ZIP_DD_MAGIC: {
+			int cmpsize;
+			seek_sub_file(zip_stream, 4); // Skip crc32
+			fread(&cmpsize, 4, 1, zip_stream);
+			archive_offset += 4;
+			if (dd_ahead == 1) archive_offset += cmpsize;
+			seek_sub_file(zip_stream, 4); // Skip uncompressed size
+			dd_ahead = 0;
+			return (get_header_zip(zip_stream));
+			break; }
+		default:
+			if (!dd_ahead) error_msg("Invalid magic (%#x): Trying to skip junk", magic);
+			dd_ahead = 0;
+			while (!feof(zip_stream)) {
+				int tmpmagic;
+				tmpmagic = fgetc(zip_stream);
+				archive_offset++;
+				magic = ((magic >> 8) & 0x00ffffff) | ((tmpmagic << 24) & 0xff000000);
+				if (magic == ZIP_FILEHEADER_MAGIC || magic == ZIP_CDS_MAGIC || magic == ZIP_CDS_END_MAGIC) goto checkmagic;
+			}
+			error_msg("End of archive reached: Bad archive");
+			return(NULL);
+	}
+	//if (archive_offset != ftell(zip_stream)) printf("Archive offset out of sync (%d,%d)\n", (int) archive_offset, (int) ftell(zip_stream));
+	return(zip_entry);
+}