/src/libzip/lib/zip_source_window.c

Source
/*
  zip_source_window.c -- return part of lower source
  Copyright (C) 2012-2025 Dieter Baron and Thomas Klausner

  This file is part of libzip, a library to manipulate ZIP archives.
  The authors can be contacted at <info@libzip.org>

  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 "zipint.h"

#include <stdlib.h>
#include <string.h>

struct window {
    zip_uint64_t start; /* where in file we start reading */
    zip_uint64_t end;   /* where in file we stop reading */
    bool end_valid;     /* whether end is set, otherwise read until EOF */

    /* if not NULL, read file data for this file */
    zip_t *source_archive;
    zip_uint64_t source_index;

    zip_uint64_t offset; /* offset in src for next read */

    zip_stat_t stat;
    zip_uint64_t stat_invalid;
    zip_file_attributes_t attributes;
    zip_dostime_t dostime;
    bool dostime_valid;
    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_EXTERN zip_source_t *zip_source_window_create(zip_source_t *src, zip_uint64_t start, zip_int64_t len, zip_error_t *error) {
    return _zip_source_window_new(src, start, len, NULL, 0, NULL, NULL, NULL, 0, false, error);
}


zip_source_t *_zip_source_window_new(zip_source_t *src, zip_uint64_t start, zip_int64_t length, zip_stat_t *st, zip_uint64_t st_invalid, zip_file_attributes_t *attributes, zip_dostime_t *dostime, zip_t *source_archive, zip_uint64_t source_index, bool take_ownership, zip_error_t *error) {
    zip_source_t *window_source;
    struct window *ctx;

    if (src == NULL || length < -1 || (source_archive == NULL && source_index != 0)) {
        zip_error_set(error, ZIP_ER_INVAL, 0);
        return NULL;
    }

    if (length >= 0) {
        if (start + (zip_uint64_t)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;
    if (length == -1) {
        ctx->end_valid = false;
    }
    else {
        ctx->end = start + (zip_uint64_t)length;
        ctx->end_valid = true;
    }
    zip_stat_init(&ctx->stat);
    ctx->stat_invalid = st_invalid;
    if (attributes != NULL) {
        (void)memcpy_s(&ctx->attributes, sizeof(ctx->attributes), attributes, sizeof(ctx->attributes));
    }
    else {
        zip_file_attributes_init(&ctx->attributes);
    }
    if (dostime != NULL) {
        ctx->dostime = *dostime;
        ctx->dostime_valid = true;
    }
    else {
        ctx->dostime_valid = false;
    }
    ctx->source_archive = source_archive;
    ctx->source_index = source_index;
    zip_error_init(&ctx->error);
    ctx->supports = (zip_source_supports(src) & (ZIP_SOURCE_SUPPORTS_SEEKABLE | ZIP_SOURCE_SUPPORTS_REOPEN)) | (zip_source_make_command_bitmap(ZIP_SOURCE_GET_FILE_ATTRIBUTES, ZIP_SOURCE_GET_DOS_TIME, ZIP_SOURCE_SUPPORTS, ZIP_SOURCE_TELL, ZIP_SOURCE_FREE, -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;
        }
    }

    window_source = zip_source_layered_create(src, window_read, ctx, error);
    if (window_source == NULL) {
        free(ctx);
        return NULL;
    }
    if (!take_ownership) {
        zip_source_keep(src);
    }
    return window_source;
}


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;

    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->source_archive) {
            zip_uint64_t offset;

            if ((offset = _zip_file_get_offset(ctx->source_archive, ctx->source_index, &ctx->error)) == 0) {
                return -1;
            }
            if (ctx->end_valid) {
                if (ctx->end + offset < ctx->end) {
                    /* zip archive data claims end of data past zip64 limits */
                    zip_error_set(&ctx->error, ZIP_ER_INCONS, MAKE_DETAIL_WITH_INDEX(ZIP_ER_DETAIL_CDIR_ENTRY_INVALID, ctx->source_index));
                    return -1;
                }
                ctx->end += offset;
            }
            ctx->start += offset;
            ctx->source_archive = NULL;
        }

        if (!ctx->needs_seek) {
            DEFINE_BYTE_ARRAY(b, BUFSIZE);

            if (!byte_array_init(b, BUFSIZE)) {
                zip_error_set(&ctx->error, ZIP_ER_MEMORY, 0);
                return -1;
            }

            for (n = 0; n < ctx->start; n += (zip_uint64_t)ret) {
                i = (ctx->start - n > BUFSIZE ? BUFSIZE : ctx->start - n);
                if ((ret = zip_source_read(src, b, i)) < 0) {
                    zip_error_set_from_source(&ctx->error, src);
                    byte_array_fini(b);
                    return -1;
                }
                if (ret == 0) {
                    zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
                    byte_array_fini(b);
                    return -1;
                }
            }

            byte_array_fini(b);
        }

        ctx->offset = ctx->start;
        return 0;

    case ZIP_SOURCE_READ:
        if (ctx->end_valid && 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->end_valid && 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;

        if (!ctx->end_valid) {
            zip_source_args_seek_t *args = ZIP_SOURCE_GET_ARGS(zip_source_args_seek_t, data, len, &ctx->error);

            if (args == NULL) {
                return -1;
            }
            if (args->whence == SEEK_END) {
                if (zip_source_seek(src, args->offset, args->whence) < 0) {
                    zip_error_set_from_source(&ctx->error, src);
                    return -1;
                }
                new_offset = zip_source_tell(src);
                if (new_offset < 0) {
                    zip_error_set_from_source(&ctx->error, src);
                    return -1;
                }
                if ((zip_uint64_t)new_offset < ctx->start) {
                    zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
                    (void)zip_source_seek(src, (zip_int64_t)ctx->offset, SEEK_SET);
                    return -1;
                }
                ctx->offset = (zip_uint64_t)new_offset;
                return 0;
            }
            else {
                if (args->whence == SEEK_CUR) {
                    if (args->offset > 0 && (zip_int64_t)ctx->offset + args->offset < args->offset) {
                        zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
                        return -1;
                    }
                    args->offset += (zip_int64_t)ctx->offset;
                }
                if (args->offset < 0) {
                    zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
                    return -1;
                }
                if (zip_source_seek(src, args->offset, SEEK_SET) < 0) {
                    zip_error_set_from_source(&ctx->error, src);
                    return -1;
                }
                ctx->offset = (zip_uint64_t)args->offset;
                return 0;
            }
        }
        else {
            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;
        }

        if (!(ctx->stat.valid & ZIP_STAT_SIZE)) {
            if (ctx->end_valid) {
                st->valid |= ZIP_STAT_SIZE;
                st->size = ctx->end - ctx->start;
            }
            else if (st->valid & ZIP_STAT_SIZE) {
                st->size -= ctx->start;
            }
        }

        st->valid &= ~ctx->stat_invalid;

        return 0;
    }

    case ZIP_SOURCE_GET_FILE_ATTRIBUTES:
        if (len < sizeof(ctx->attributes)) {
            zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
            return -1;
        }

        (void)memcpy_s(data, sizeof(ctx->attributes), &ctx->attributes, sizeof(ctx->attributes));
        return sizeof(ctx->attributes);

    case ZIP_SOURCE_GET_DOS_TIME:
        if (len < sizeof(ctx->dostime)) {
            zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
            return -1;
        }
        if (ctx->dostime_valid) {
            (void)memcpy_s(data, sizeof(ctx->dostime), &ctx->dostime, sizeof(ctx->dostime));
            return sizeof(ctx->dostime);
        }
        else {
            return 0;
        }

    case ZIP_SOURCE_SUPPORTS:
        return ctx->supports;

    case ZIP_SOURCE_TELL:
        return (zip_int64_t)(ctx->offset - ctx->start);

    default:
        return zip_source_pass_to_lower_layer(src, data, len, cmd);
    }
}


void _zip_deregister_source(zip_t *za, zip_source_t *src) {
    zip_uint64_t 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) {
    if (za->nopen_source + 1 >= za->nopen_source_alloc) {
        if (!ZIP_REALLOC(za->open_source, za->nopen_source_alloc, 10, &za->error)) {
            return -1;
        }
    }

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

    return 0;
}

Coverage Report

Created: 2026-06-16 07:20

Line	Count	Source
1		/*
2		zip_source_window.c -- return part of lower source
3		Copyright (C) 2012-2025 Dieter Baron and Thomas Klausner
4
5		This file is part of libzip, a library to manipulate ZIP archives.
6		The authors can be contacted at <info@libzip.org>
7
8		Redistribution and use in source and binary forms, with or without
9		modification, are permitted provided that the following conditions
10		are met:
11		1. Redistributions of source code must retain the above copyright
12		notice, this list of conditions and the following disclaimer.
13		2. Redistributions in binary form must reproduce the above copyright
14		notice, this list of conditions and the following disclaimer in
15		the documentation and/or other materials provided with the
16		distribution.
17		3. The names of the authors may not be used to endorse or promote
18		products derived from this software without specific prior
19		written permission.
20
21		THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
22		OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
23		WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24		ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
25		DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26		DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
27		GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28		INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
29		IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
30		OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
31		IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32		*/
33
34		#include "zipint.h"
35
36		#include <stdlib.h>
37		#include <string.h>
38
39		struct window {
40		zip_uint64_t start; /* where in file we start reading */
41		zip_uint64_t end; /* where in file we stop reading */
42		bool end_valid; /* whether end is set, otherwise read until EOF */
43
44		/* if not NULL, read file data for this file */
45		zip_t *source_archive;
46		zip_uint64_t source_index;
47
48		zip_uint64_t offset; /* offset in src for next read */
49
50		zip_stat_t stat;
51		zip_uint64_t stat_invalid;
52		zip_file_attributes_t attributes;
53		zip_dostime_t dostime;
54		bool dostime_valid;
55		zip_error_t error;
56		zip_int64_t supports;
57		bool needs_seek;
58		};
59
60		static zip_int64_t window_read(zip_source_t , void , void *, zip_uint64_t, zip_source_cmd_t);
61
62
63	0	ZIP_EXTERN zip_source_t zip_source_window_create(zip_source_t src, zip_uint64_t start, zip_int64_t len, zip_error_t *error) {
64	0	return _zip_source_window_new(src, start, len, NULL, 0, NULL, NULL, NULL, 0, false, error);
65	0	}
66
67
68	0	zip_source_t _zip_source_window_new(zip_source_t src, zip_uint64_t start, zip_int64_t length, zip_stat_t st, zip_uint64_t st_invalid, zip_file_attributes_t attributes, zip_dostime_t dostime, zip_t source_archive, zip_uint64_t source_index, bool take_ownership, zip_error_t *error) {
69	0	zip_source_t *window_source;
70	0	struct window *ctx;
71
72	0	if (src == NULL \|\| length < -1 \|\| (source_archive == NULL && source_index != 0)) {
73	0	zip_error_set(error, ZIP_ER_INVAL, 0);
74	0	return NULL;
75	0	}
76
77	0	if (length >= 0) {
78	0	if (start + (zip_uint64_t)length < start) {
79	0	zip_error_set(error, ZIP_ER_INVAL, 0);
80	0	return NULL;
81	0	}
82	0	}
83
84	0	if ((ctx = (struct window )malloc(sizeof(ctx))) == NULL) {
85	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
86	0	return NULL;
87	0	}
88
89	0	ctx->start = start;
90	0	if (length == -1) {
91	0	ctx->end_valid = false;
92	0	}
93	0	else {
94	0	ctx->end = start + (zip_uint64_t)length;
95	0	ctx->end_valid = true;
96	0	}
97	0	zip_stat_init(&ctx->stat);
98	0	ctx->stat_invalid = st_invalid;
99	0	if (attributes != NULL) {
100	0	(void)memcpy_s(&ctx->attributes, sizeof(ctx->attributes), attributes, sizeof(ctx->attributes));
101	0	}
102	0	else {
103	0	zip_file_attributes_init(&ctx->attributes);
104	0	}
105	0	if (dostime != NULL) {
106	0	ctx->dostime = *dostime;
107	0	ctx->dostime_valid = true;
108	0	}
109	0	else {
110	0	ctx->dostime_valid = false;
111	0	}
112	0	ctx->source_archive = source_archive;
113	0	ctx->source_index = source_index;
114	0	zip_error_init(&ctx->error);
115	0	ctx->supports = (zip_source_supports(src) & (ZIP_SOURCE_SUPPORTS_SEEKABLE \| ZIP_SOURCE_SUPPORTS_REOPEN)) \| (zip_source_make_command_bitmap(ZIP_SOURCE_GET_FILE_ATTRIBUTES, ZIP_SOURCE_GET_DOS_TIME, ZIP_SOURCE_SUPPORTS, ZIP_SOURCE_TELL, ZIP_SOURCE_FREE, -1));
116	0	ctx->needs_seek = (ctx->supports & ZIP_SOURCE_MAKE_COMMAND_BITMASK(ZIP_SOURCE_SEEK)) ? true : false;
117
118	0	if (st) {
119	0	if (_zip_stat_merge(&ctx->stat, st, error) < 0) {
120	0	free(ctx);
121	0	return NULL;
122	0	}
123	0	}
124
125	0	window_source = zip_source_layered_create(src, window_read, ctx, error);
126	0	if (window_source == NULL) {
127	0	free(ctx);
128	0	return NULL;
129	0	}
130	0	if (!take_ownership) {
131	0	zip_source_keep(src);
132	0	}
133	0	return window_source;
134	0	}
135
136
137	0	int _zip_source_set_source_archive(zip_source_t src, zip_t za) {
138	0	src->source_archive = za;
139	0	return _zip_register_source(za, src);
140	0	}
141
142
143		/* called by zip_discard to avoid operating on file from closed archive */
144	0	void _zip_source_invalidate(zip_source_t *src) {
145	0	src->source_closed = 1;
146
147	0	if (zip_error_code_zip(&src->error) == ZIP_ER_OK) {
148	0	zip_error_set(&src->error, ZIP_ER_ZIPCLOSED, 0);
149	0	}
150	0	}
151
152
153	0	static zip_int64_t window_read(zip_source_t src, void _ctx, void *data, zip_uint64_t len, zip_source_cmd_t cmd) {
154	0	struct window *ctx;
155	0	zip_int64_t ret;
156	0	zip_uint64_t n, i;
157
158	0	ctx = (struct window *)_ctx;
159
160	0	switch (cmd) {
161	0	case ZIP_SOURCE_CLOSE:
162	0	return 0;
163
164	0	case ZIP_SOURCE_ERROR:
165	0	return zip_error_to_data(&ctx->error, data, len);
166
167	0	case ZIP_SOURCE_FREE:
168	0	free(ctx);
169	0	return 0;
170
171	0	case ZIP_SOURCE_OPEN:
172	0	if (ctx->source_archive) {
173	0	zip_uint64_t offset;
174
175	0	if ((offset = _zip_file_get_offset(ctx->source_archive, ctx->source_index, &ctx->error)) == 0) {
176	0	return -1;
177	0	}
178	0	if (ctx->end_valid) {
179	0	if (ctx->end + offset < ctx->end) {
180		/* zip archive data claims end of data past zip64 limits */
181	0	zip_error_set(&ctx->error, ZIP_ER_INCONS, MAKE_DETAIL_WITH_INDEX(ZIP_ER_DETAIL_CDIR_ENTRY_INVALID, ctx->source_index));
182	0	return -1;
183	0	}
184	0	ctx->end += offset;
185	0	}
186	0	ctx->start += offset;
187	0	ctx->source_archive = NULL;
188	0	}
189
190	0	if (!ctx->needs_seek) {
191	0	DEFINE_BYTE_ARRAY(b, BUFSIZE);
192
193	0	if (!byte_array_init(b, BUFSIZE)) {
194	0	zip_error_set(&ctx->error, ZIP_ER_MEMORY, 0);
195	0	return -1;
196	0	}
197
198	0	for (n = 0; n < ctx->start; n += (zip_uint64_t)ret) {
199	0	i = (ctx->start - n > BUFSIZE ? BUFSIZE : ctx->start - n);
200	0	if ((ret = zip_source_read(src, b, i)) < 0) {
201	0	zip_error_set_from_source(&ctx->error, src);
202	0	byte_array_fini(b);
203	0	return -1;
204	0	}
205	0	if (ret == 0) {
206	0	zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
207	0	byte_array_fini(b);
208	0	return -1;
209	0	}
210	0	}
211
212	0	byte_array_fini(b);
213	0	}
214
215	0	ctx->offset = ctx->start;
216	0	return 0;
217
218	0	case ZIP_SOURCE_READ:
219	0	if (ctx->end_valid && len > ctx->end - ctx->offset) {
220	0	len = ctx->end - ctx->offset;
221	0	}
222
223	0	if (len == 0) {
224	0	return 0;
225	0	}
226
227	0	if (ctx->needs_seek) {
228	0	if (zip_source_seek(src, (zip_int64_t)ctx->offset, SEEK_SET) < 0) {
229	0	zip_error_set_from_source(&ctx->error, src);
230	0	return -1;
231	0	}
232	0	}
233
234	0	if ((ret = zip_source_read(src, data, len)) < 0) {
235	0	zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
236	0	return -1;
237	0	}
238
239	0	ctx->offset += (zip_uint64_t)ret;
240
241	0	if (ret == 0) {
242	0	if (ctx->end_valid && ctx->offset < ctx->end) {
243	0	zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
244	0	return -1;
245	0	}
246	0	}
247	0	return ret;
248
249	0	case ZIP_SOURCE_SEEK: {
250	0	zip_int64_t new_offset;
251
252	0	if (!ctx->end_valid) {
253	0	zip_source_args_seek_t *args = ZIP_SOURCE_GET_ARGS(zip_source_args_seek_t, data, len, &ctx->error);
254
255	0	if (args == NULL) {
256	0	return -1;
257	0	}
258	0	if (args->whence == SEEK_END) {
259	0	if (zip_source_seek(src, args->offset, args->whence) < 0) {
260	0	zip_error_set_from_source(&ctx->error, src);
261	0	return -1;
262	0	}
263	0	new_offset = zip_source_tell(src);
264	0	if (new_offset < 0) {
265	0	zip_error_set_from_source(&ctx->error, src);
266	0	return -1;
267	0	}
268	0	if ((zip_uint64_t)new_offset < ctx->start) {
269	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
270	0	(void)zip_source_seek(src, (zip_int64_t)ctx->offset, SEEK_SET);
271	0	return -1;
272	0	}
273	0	ctx->offset = (zip_uint64_t)new_offset;
274	0	return 0;
275	0	}
276	0	else {
277	0	if (args->whence == SEEK_CUR) {
278	0	if (args->offset > 0 && (zip_int64_t)ctx->offset + args->offset < args->offset) {
279	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
280	0	return -1;
281	0	}
282	0	args->offset += (zip_int64_t)ctx->offset;
283	0	}
284	0	if (args->offset < 0) {
285	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
286	0	return -1;
287	0	}
288	0	if (zip_source_seek(src, args->offset, SEEK_SET) < 0) {
289	0	zip_error_set_from_source(&ctx->error, src);
290	0	return -1;
291	0	}
292	0	ctx->offset = (zip_uint64_t)args->offset;
293	0	return 0;
294	0	}
295	0	}
296	0	else {
297	0	new_offset = zip_source_seek_compute_offset(ctx->offset - ctx->start, ctx->end - ctx->start, data, len, &ctx->error);
298
299	0	if (new_offset < 0) {
300	0	return -1;
301	0	}
302
303	0	ctx->offset = (zip_uint64_t)new_offset + ctx->start;
304	0	return 0;
305	0	}
306	0	}
307
308	0	case ZIP_SOURCE_STAT: {
309	0	zip_stat_t *st;
310
311	0	st = (zip_stat_t *)data;
312
313	0	if (_zip_stat_merge(st, &ctx->stat, &ctx->error) < 0) {
314	0	return -1;
315	0	}
316
317	0	if (!(ctx->stat.valid & ZIP_STAT_SIZE)) {
318	0	if (ctx->end_valid) {
319	0	st->valid \|= ZIP_STAT_SIZE;
320	0	st->size = ctx->end - ctx->start;
321	0	}
322	0	else if (st->valid & ZIP_STAT_SIZE) {
323	0	st->size -= ctx->start;
324	0	}
325	0	}
326
327	0	st->valid &= ~ctx->stat_invalid;
328
329	0	return 0;
330	0	}
331
332	0	case ZIP_SOURCE_GET_FILE_ATTRIBUTES:
333	0	if (len < sizeof(ctx->attributes)) {
334	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
335	0	return -1;
336	0	}
337
338	0	(void)memcpy_s(data, sizeof(ctx->attributes), &ctx->attributes, sizeof(ctx->attributes));
339	0	return sizeof(ctx->attributes);
340
341	0	case ZIP_SOURCE_GET_DOS_TIME:
342	0	if (len < sizeof(ctx->dostime)) {
343	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
344	0	return -1;
345	0	}
346	0	if (ctx->dostime_valid) {
347	0	(void)memcpy_s(data, sizeof(ctx->dostime), &ctx->dostime, sizeof(ctx->dostime));
348	0	return sizeof(ctx->dostime);
349	0	}
350	0	else {
351	0	return 0;
352	0	}
353
354	0	case ZIP_SOURCE_SUPPORTS:
355	0	return ctx->supports;
356
357	0	case ZIP_SOURCE_TELL:
358	0	return (zip_int64_t)(ctx->offset - ctx->start);
359
360	0	default:
361	0	return zip_source_pass_to_lower_layer(src, data, len, cmd);
362	0	}
363	0	}
364
365
366	0	void _zip_deregister_source(zip_t za, zip_source_t src) {
367	0	zip_uint64_t i;
368
369	0	for (i = 0; i < za->nopen_source; i++) {
370	0	if (za->open_source[i] == src) {
371	0	za->open_source[i] = za->open_source[za->nopen_source - 1];
372	0	za->nopen_source--;
373	0	break;
374	0	}
375	0	}
376	0	}
377
378
379	0	int _zip_register_source(zip_t za, zip_source_t src) {
380	0	if (za->nopen_source + 1 >= za->nopen_source_alloc) {
381	0	if (!ZIP_REALLOC(za->open_source, za->nopen_source_alloc, 10, &za->error)) {
382	0	return -1;
383	0	}
384	0	}
385
386	0	za->open_source[za->nopen_source++] = src;
387
388	0	return 0;
389	0	}