+/*

+ zip_source_window.c -- return part of lower source

+ Copyright (C) 2012-2014 Dieter Baron and Thomas Klausner

+

+ This file is part of libzip, a library to manipulate ZIP archives.

+ The authors can be contacted at <libzip@nih.at>

+

+ Redistribution and use in source and binary forms, with or without

+ modification, are permitted provided that the following conditions

+ are met:

+ 1. Redistributions of source code must retain the above copyright

+ notice, this list of conditions and the following disclaimer.

+ 2. Redistributions in binary form must reproduce the above copyright

+ notice, this list of conditions and the following disclaimer in

+ the documentation and/or other materials provided with the

+ distribution.

+ 3. The names of the authors may not be used to endorse or promote

+ products derived from this software without specific prior

+ written permission.

+

+ THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS

+ OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

+ WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

+ ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY

+ DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE

+ GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

+ INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER

+ IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR

+ OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN

+ IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

+*/

+

+

+#include <stdlib.h>

+#include <string.h>

+

+#include "zipint.h"

+

+struct window {

+ zip_uint64_t start;

+ zip_uint64_t end;

+ zip_uint64_t offset;

+ zip_stat_t stat;

+ zip_error_t error;

+ zip_int64_t supports;

+ bool needs_seek;

+};

+

+static zip_int64_t window_read(zip_source_t *, void *, void *, zip_uint64_t, zip_source_cmd_t);

+

+

+zip_source_t *

+zip_source_window(zip_t *za, zip_source_t *src, zip_uint64_t start, zip_uint64_t len)

+{

+ return _zip_source_window_new(src, start, len, NULL, &za->error);

+}

+

+

+zip_source_t *

+_zip_source_window_new(zip_source_t *src, zip_uint64_t start, zip_uint64_t length, zip_stat_t *st, zip_error_t *error)

+{

+ struct window *ctx;

+

+ if (src == NULL || start + length < start) {

+ zip_error_set(error, ZIP_ER_INVAL, 0);

+ return NULL;

+ }

+

+ if ((ctx=(struct window *)malloc(sizeof(*ctx))) == NULL) {

+ zip_error_set(error, ZIP_ER_MEMORY, 0);

+ return NULL;

+ }

+

+ ctx->start = start;

+ ctx->end = start + length;

+ zip_stat_init(&ctx->stat);

+ zip_error_init(&ctx->error);

+ ctx->supports = (zip_source_supports(src) & ZIP_SOURCE_SUPPORTS_SEEKABLE) | (zip_source_make_command_bitmap(ZIP_SOURCE_SUPPORTS, ZIP_SOURCE_TELL, -1));

+ ctx->needs_seek = (ctx->supports & ZIP_SOURCE_MAKE_COMMAND_BITMASK(ZIP_SOURCE_SEEK)) ? true : false;

+

+ if (st) {

+ if (_zip_stat_merge(&ctx->stat, st, error) < 0) {

+ free(ctx);

+ return NULL;

+ }

+ }

+

+ return zip_source_layered_create(src, window_read, ctx, error);

+}

+

+

+int

+_zip_source_set_source_archive(zip_source_t *src, zip_t *za)

+{

+ src->source_archive = za;

+ return _zip_register_source(za, src);

+}

+

+

+/* called by zip_discard to avoid operating on file from closed archive */

+void

+_zip_source_invalidate(zip_source_t *src)

+{

+ src->source_closed = 1;

+

+ if (zip_error_code_zip(&src->error) == ZIP_ER_OK) {

+ zip_error_set(&src->error, ZIP_ER_ZIPCLOSED, 0);

+ }

+}

+

+

+static zip_int64_t

+window_read(zip_source_t *src, void *_ctx, void *data, zip_uint64_t len, zip_source_cmd_t cmd)

+{

+ struct window *ctx;

+ zip_int64_t ret;

+ zip_uint64_t n, i;

+ char b[8192];

+

+ ctx = (struct window *)_ctx;

+

+ switch (cmd) {

+ case ZIP_SOURCE_CLOSE:

+ return 0;

+

+ case ZIP_SOURCE_ERROR:

+ return zip_error_to_data(&ctx->error, data, len);

+

+ case ZIP_SOURCE_FREE:

+ free(ctx);

+ return 0;

+

+ case ZIP_SOURCE_OPEN:

+ if (!ctx->needs_seek) {

+ for (n=0; n<ctx->start; n+=(zip_uint64_t)ret) {

+ i = (ctx->start-n > sizeof(b) ? sizeof(b) : ctx->start-n);

+ if ((ret=zip_source_read(src, b, i)) < 0) {

+ _zip_error_set_from_source(&ctx->error, src);

+ return -1;

+ }

+ if (ret==0) {

+ zip_error_set(&ctx->error, ZIP_ER_EOF, 0);

+ return -1;

+ }

+ }

+

+ }

+ ctx->offset = ctx->start;

+ return 0;

+

+ case ZIP_SOURCE_READ:

+ if (len > ctx->end - ctx->offset)

+ len = ctx->end - ctx->offset;

+

+ if (len == 0)

+ return 0;

+

+ if (ctx->needs_seek) {

+ if (zip_source_seek(src, (zip_int64_t)ctx->offset, SEEK_SET) < 0) {

+ _zip_error_set_from_source(&ctx->error, src);

+ return -1;

+ }

+ }

+

+ if ((ret=zip_source_read(src, data, len)) < 0) {

+ zip_error_set(&ctx->error, ZIP_ER_EOF, 0);

+ return -1;

+ }

+

+ ctx->offset += (zip_uint64_t)ret;

+

+ if (ret == 0) {

+ if (ctx->offset < ctx->end) {

+ zip_error_set(&ctx->error, ZIP_ER_EOF, 0);

+ return -1;

+ }

+ }

+ return ret;

+

+ case ZIP_SOURCE_SEEK:

+ {

+ zip_int64_t new_offset = zip_source_seek_compute_offset(ctx->offset - ctx->start, ctx->end - ctx->start, data, len, &ctx->error);

+

+ if (new_offset < 0) {

+ return -1;

+ }

+

+ ctx->offset = (zip_uint64_t)new_offset + ctx->start;

+ return 0;

+ }

+

+ case ZIP_SOURCE_STAT:

+ {

+ zip_stat_t *st;

+

+ st = (zip_stat_t *)data;

+

+ if (_zip_stat_merge(st, &ctx->stat, &ctx->error) < 0) {

+ return -1;

+ }

+ return 0;

+ }

+

+ case ZIP_SOURCE_SUPPORTS:

+ return ctx->supports;

+

+ case ZIP_SOURCE_TELL:

+ return (zip_int64_t)(ctx->offset - ctx->start);

+

+ default:

+ zip_error_set(&ctx->error, ZIP_ER_OPNOTSUPP, 0);

+ return -1;

+ }

+}

+

+

+void

+_zip_deregister_source(zip_t *za, zip_source_t *src)

+{

+ unsigned int i;

+

+ for (i=0; i<za->nopen_source; i++) {

+ if (za->open_source[i] == src) {

+ za->open_source[i] = za->open_source[za->nopen_source-1];

+ za->nopen_source--;

+ break;

+ }

+ }

+}

+

+

+int

+_zip_register_source(zip_t *za, zip_source_t *src)

+{

+ zip_source_t **open_source;

+

+ if (za->nopen_source+1 >= za->nopen_source_alloc) {

+ unsigned int n;

+ n = za->nopen_source_alloc + 10;

+ open_source = (zip_source_t **)realloc(za->open_source, n*sizeof(zip_source_t *));

+ if (open_source == NULL) {

+ zip_error_set(&za->error, ZIP_ER_MEMORY, 0);

+ return -1;

+ }

+ za->nopen_source_alloc = n;

+ za->open_source = open_source;

+ }

+

+ za->open_source[za->nopen_source++] = src;

+

+ return 0;

+}