151 lines
3.7 KiB
C
151 lines
3.7 KiB
C
/*
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zip_source_window.c -- return part of lower source
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Copyright (C) 2012-2013 Dieter Baron and Thomas Klausner
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This file is part of libzip, a library to manipulate ZIP archives.
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The authors can be contacted at <libzip@nih.at>
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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3. The names of the authors may not be used to endorse or promote
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products derived from this software without specific prior
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written permission.
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THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
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OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
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IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
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IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdlib.h>
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#include <string.h>
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#include "zipint.h"
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struct window {
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zip_uint64_t skip;
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zip_uint64_t len;
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zip_uint64_t left;
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int e[2];
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};
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static zip_int64_t window_read(struct zip_source *, void *, void *,
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zip_uint64_t, enum zip_source_cmd);
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struct zip_source *
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zip_source_window(struct zip *za, struct zip_source *src, zip_uint64_t start, zip_uint64_t len)
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{
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struct window *ctx;
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if (src == NULL) {
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_zip_error_set(&za->error, ZIP_ER_INVAL, 0);
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return NULL;
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}
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if ((ctx=(struct window *)malloc(sizeof(*ctx))) == NULL) {
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_zip_error_set(&za->error, ZIP_ER_MEMORY, 0);
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return NULL;
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}
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ctx->skip = start;
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ctx->len = len;
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ctx->left = len;
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return zip_source_layered(za, src, window_read, ctx);
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}
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static zip_int64_t
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window_read(struct zip_source *src, void *_ctx, void *data,
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zip_uint64_t len, enum zip_source_cmd cmd)
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{
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struct window *ctx;
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zip_int64_t ret;
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zip_uint64_t n, i;
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char b[8192];
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ctx = (struct window *)_ctx;
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switch (cmd) {
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case ZIP_SOURCE_OPEN:
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for (n=0; n<ctx->skip; n+=(zip_uint64_t)ret) {
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i = (ctx->skip-n > sizeof(b) ? sizeof(b) : ctx->skip-n);
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if ((ret=zip_source_read(src, b, i)) < 0)
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return ZIP_SOURCE_ERR_LOWER;
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if (ret==0) {
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ctx->e[0] = ZIP_ER_EOF;
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ctx->e[1] = 0;
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return -1;
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}
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}
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return 0;
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case ZIP_SOURCE_READ:
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if (len > ctx->left)
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len = ctx->left;
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if (len == 0)
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return 0;
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if ((ret=zip_source_read(src, data, len)) < 0)
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return ZIP_SOURCE_ERR_LOWER;
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ctx->left -= (zip_uint64_t)ret;
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if (ret == 0) {
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if (ctx->left > 0) {
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ctx->e[0] = ZIP_ER_EOF;
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ctx->e[1] = 0;
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return -1;
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}
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}
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return ret;
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case ZIP_SOURCE_CLOSE:
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return 0;
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case ZIP_SOURCE_STAT:
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{
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struct zip_stat *st;
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st = (struct zip_stat *)data;
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st->size = ctx->len;
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st->valid |= ZIP_STAT_SIZE;
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st->valid &= ~(ZIP_STAT_CRC|ZIP_STAT_COMP_SIZE);
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}
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return 0;
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case ZIP_SOURCE_ERROR:
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memcpy(data, ctx->e, sizeof(ctx->e));
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return 0;
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case ZIP_SOURCE_FREE:
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free(ctx);
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return 0;
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default:
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return -1;
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}
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}
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