/src/libzip/lib/zip_source_buffer.c

Source
/*
  zip_source_buffer.c -- create zip data source from buffer
  Copyright (C) 1999-2025 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>

#ifndef WRITE_FRAGMENT_SIZE
#define WRITE_FRAGMENT_SIZE (64 * 1024)
#endif

struct buffer {
    zip_buffer_fragment_t *fragments; /* fragments */
    zip_uint64_t *fragment_offsets;   /* offset of each fragment from start of buffer, nfragments+1 entries */
    zip_uint64_t nfragments;          /* number of allocated fragments */
    zip_uint64_t fragments_capacity;  /* size of fragments (number of pointers) */

    zip_uint64_t first_owned_fragment; /* first fragment to free data from */

    zip_uint64_t shared_fragments; /* number of shared fragments */
    struct buffer *shared_buffer;  /* buffer fragments are shared with */

    zip_uint64_t size;             /* size of buffer */
    zip_uint64_t offset;           /* current offset in buffer */
    zip_uint64_t current_fragment; /* fragment current offset is in */
};

typedef struct buffer buffer_t;

struct read_data {
    zip_error_t error;
    time_t mtime;
    zip_file_attributes_t attributes;
    buffer_t *in;
    buffer_t *out;
};

#define buffer_capacity(buffer) ((buffer)->fragment_offsets[(buffer)->nfragments])
#define buffer_size(buffer) ((buffer)->size)

static buffer_t *buffer_clone(buffer_t *buffer, zip_uint64_t length, zip_error_t *error);
static zip_uint64_t buffer_find_fragment(const buffer_t *buffer, zip_uint64_t offset);
static void buffer_free(buffer_t *buffer);
static bool buffer_grow_fragments(buffer_t *buffer, zip_uint64_t capacity, zip_error_t *error);
static buffer_t *buffer_new(const zip_buffer_fragment_t *fragments, zip_uint64_t nfragments, int free_data, zip_error_t *error);
static zip_int64_t buffer_read(buffer_t *buffer, zip_uint8_t *data, zip_uint64_t length);
static int buffer_seek(buffer_t *buffer, void *data, zip_uint64_t len, zip_error_t *error);
static zip_int64_t buffer_write(buffer_t *buffer, const zip_uint8_t *data, zip_uint64_t length, zip_error_t *);

static zip_int64_t read_data(void *, void *, zip_uint64_t, zip_source_cmd_t);

zip_source_t *zip_source_buffer_with_attributes_create(const void *data, zip_uint64_t len, int freep, zip_file_attributes_t *attributes, zip_error_t *error);
zip_source_t *zip_source_buffer_fragment_with_attributes_create(const zip_buffer_fragment_t *fragments, zip_uint64_t nfragments, int freep, zip_file_attributes_t *attributes, zip_error_t *error);


ZIP_EXTERN zip_source_t *zip_source_buffer(zip_t *za, const void *data, zip_uint64_t len, int freep) {
    if (za == NULL) {
        return NULL;
    }

    return zip_source_buffer_with_attributes_create(data, len, freep, NULL, &za->error);
}


ZIP_EXTERN zip_source_t *zip_source_buffer_create(const void *data, zip_uint64_t len, int freep, zip_error_t *error) {
    return zip_source_buffer_with_attributes_create(data, len, freep, NULL, error);
}


zip_source_t *zip_source_buffer_with_attributes_create(const void *data, zip_uint64_t len, int freep, zip_file_attributes_t *attributes, zip_error_t *error) {
    zip_buffer_fragment_t fragment;

    if (data == NULL) {
        if (len > 0) {
            zip_error_set(error, ZIP_ER_INVAL, 0);
            return NULL;
        }

        return zip_source_buffer_fragment_with_attributes_create(NULL, 0, freep, attributes, error);
    }

    fragment.data = (zip_uint8_t *)data;
    fragment.length = len;

    return zip_source_buffer_fragment_with_attributes_create(&fragment, 1, freep, attributes, error);
}


ZIP_EXTERN zip_source_t *zip_source_buffer_fragment(zip_t *za, const zip_buffer_fragment_t *fragments, zip_uint64_t nfragments, int freep) {
    if (za == NULL) {
        return NULL;
    }

    return zip_source_buffer_fragment_with_attributes_create(fragments, nfragments, freep, NULL, &za->error);
}


ZIP_EXTERN zip_source_t *zip_source_buffer_fragment_create(const zip_buffer_fragment_t *fragments, zip_uint64_t nfragments, int freep, zip_error_t *error) {
    return zip_source_buffer_fragment_with_attributes_create(fragments, nfragments, freep, NULL, error);
}

zip_source_t *zip_source_buffer_fragment_with_attributes_create(const zip_buffer_fragment_t *fragments, zip_uint64_t nfragments, int freep, zip_file_attributes_t *attributes, zip_error_t *error) {
    struct read_data *ctx;
    zip_source_t *zs;
    buffer_t *buffer;

    if (fragments == NULL && nfragments > 0) {
        zip_error_set(error, ZIP_ER_INVAL, 0);
        return NULL;
    }

    if ((buffer = buffer_new(fragments, nfragments, freep, error)) == NULL) {
        return NULL;
    }

    if ((ctx = (struct read_data *)malloc(sizeof(*ctx))) == NULL) {
        zip_error_set(error, ZIP_ER_MEMORY, 0);
        buffer_free(buffer);
        return NULL;
    }

    ctx->in = buffer;
    ctx->out = NULL;
    ctx->mtime = time(NULL);
    if (attributes) {
        (void)memcpy_s(&ctx->attributes, sizeof(ctx->attributes), attributes, sizeof(ctx->attributes));
    }
    else {
        zip_file_attributes_init(&ctx->attributes);
    }
    zip_error_init(&ctx->error);

    if ((zs = zip_source_function_create(read_data, ctx, error)) == NULL) {
        buffer_free(ctx->in);
        free(ctx);
        return NULL;
    }

    return zs;
}


zip_source_t *zip_source_buffer_with_attributes(zip_t *za, const void *data, zip_uint64_t len, int freep, zip_file_attributes_t *attributes) {
    return zip_source_buffer_with_attributes_create(data, len, freep, attributes, &za->error);
}

static zip_int64_t read_data(void *state, void *data, zip_uint64_t len, zip_source_cmd_t cmd) {
    struct read_data *ctx = (struct read_data *)state;

    switch (cmd) {
    case ZIP_SOURCE_BEGIN_WRITE:
        if ((ctx->out = buffer_new(NULL, 0, 0, &ctx->error)) == NULL) {
            return -1;
        }
        ctx->out->offset = 0;
        ctx->out->current_fragment = 0;
        return 0;

    case ZIP_SOURCE_BEGIN_WRITE_CLONING:
        if ((ctx->out = buffer_clone(ctx->in, len, &ctx->error)) == NULL) {
            return -1;
        }
        ctx->out->offset = len;
        ctx->out->current_fragment = ctx->out->nfragments;
        return 0;

    case ZIP_SOURCE_CLOSE:
        return 0;

    case ZIP_SOURCE_COMMIT_WRITE:
        buffer_free(ctx->in);
        ctx->in = ctx->out;
        ctx->out = NULL;
        return 0;

    case ZIP_SOURCE_ERROR:
        return zip_error_to_data(&ctx->error, data, len);

    case ZIP_SOURCE_FREE:
        buffer_free(ctx->in);
        buffer_free(ctx->out);
        free(ctx);
        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_OPEN:
        ctx->in->offset = 0;
        ctx->in->current_fragment = 0;
        return 0;

    case ZIP_SOURCE_READ:
        if (len > ZIP_INT64_MAX) {
            zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
            return -1;
        }
        return buffer_read(ctx->in, data, len);

    case ZIP_SOURCE_REMOVE: {
        buffer_t *empty = buffer_new(NULL, 0, 0, &ctx->error);
        if (empty == NULL) {
            return -1;
        }

        buffer_free(ctx->in);
        ctx->in = empty;
        return 0;
    }

    case ZIP_SOURCE_ROLLBACK_WRITE:
        buffer_free(ctx->out);
        ctx->out = NULL;
        return 0;

    case ZIP_SOURCE_SEEK:
        return buffer_seek(ctx->in, data, len, &ctx->error);

    case ZIP_SOURCE_SEEK_WRITE:
        return buffer_seek(ctx->out, data, len, &ctx->error);

    case ZIP_SOURCE_STAT: {
        zip_stat_t *st;

        if (len < sizeof(*st)) {
            zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
            return -1;
        }

        st = (zip_stat_t *)data;

        zip_stat_init(st);
        st->mtime = ctx->mtime;
        st->size = ctx->in->size;
        st->comp_size = st->size;
        st->comp_method = ZIP_CM_STORE;
        st->encryption_method = ZIP_EM_NONE;
        st->valid = ZIP_STAT_MTIME | ZIP_STAT_SIZE | ZIP_STAT_COMP_SIZE | ZIP_STAT_COMP_METHOD | ZIP_STAT_ENCRYPTION_METHOD;

        return sizeof(*st);
    }

    case ZIP_SOURCE_SUPPORTS:
        return zip_source_make_command_bitmap(ZIP_SOURCE_GET_FILE_ATTRIBUTES, ZIP_SOURCE_OPEN, ZIP_SOURCE_READ, ZIP_SOURCE_CLOSE, ZIP_SOURCE_STAT, ZIP_SOURCE_ERROR, ZIP_SOURCE_FREE, ZIP_SOURCE_SEEK, ZIP_SOURCE_TELL, ZIP_SOURCE_BEGIN_WRITE, ZIP_SOURCE_BEGIN_WRITE_CLONING, ZIP_SOURCE_COMMIT_WRITE, ZIP_SOURCE_REMOVE, ZIP_SOURCE_ROLLBACK_WRITE, ZIP_SOURCE_SEEK_WRITE, ZIP_SOURCE_TELL_WRITE, ZIP_SOURCE_WRITE, ZIP_SOURCE_SUPPORTS_REOPEN, -1);

    case ZIP_SOURCE_TELL:
        if (ctx->in->offset > ZIP_INT64_MAX) {
            zip_error_set(&ctx->error, ZIP_ER_TELL, EOVERFLOW);
            return -1;
        }
        return (zip_int64_t)ctx->in->offset;


    case ZIP_SOURCE_TELL_WRITE:
        if (ctx->out->offset > ZIP_INT64_MAX) {
            zip_error_set(&ctx->error, ZIP_ER_TELL, EOVERFLOW);
            return -1;
        }
        return (zip_int64_t)ctx->out->offset;

    case ZIP_SOURCE_WRITE:
        if (len > ZIP_INT64_MAX) {
            zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
            return -1;
        }
        return buffer_write(ctx->out, data, len, &ctx->error);

    default:
        zip_error_set(&ctx->error, ZIP_ER_OPNOTSUPP, 0);
        return -1;
    }
}


static buffer_t *buffer_clone(buffer_t *buffer, zip_uint64_t offset, zip_error_t *error) {
    zip_uint64_t fragment, fragment_offset, waste;
    buffer_t *clone;

    if (offset == 0) {
        return buffer_new(NULL, 0, 1, error);
    }

    if (offset > buffer->size) {
        zip_error_set(error, ZIP_ER_INVAL, 0);
        return NULL;
    }
    if (buffer->shared_buffer != NULL) {
        zip_error_set(error, ZIP_ER_INUSE, 0);
        return NULL;
    }

    fragment = buffer_find_fragment(buffer, offset);
    fragment_offset = offset - buffer->fragment_offsets[fragment];

    if (fragment_offset == 0) {
        /* We can't be at beginning of fragment zero if offset > 0. */
        fragment--;
        fragment_offset = buffer->fragments[fragment].length;
    }

    /* TODO: This should also consider the length of the fully shared fragments */
    waste = buffer->fragments[fragment].length - fragment_offset;
    if (waste > offset) {
        zip_error_set(error, ZIP_ER_OPNOTSUPP, 0);
        return NULL;
    }

    if ((clone = buffer_new(buffer->fragments, fragment + 1, 0, error)) == NULL) {
        return NULL;
    }

#ifndef __clang_analyzer__
    /* clone->fragments can't be null, since it was created with at least one fragment */
    clone->fragments[fragment].length = fragment_offset;
#endif
    clone->fragment_offsets[clone->nfragments] = offset;
    clone->size = offset;

    clone->first_owned_fragment = ZIP_MIN(buffer->first_owned_fragment, clone->nfragments);

    buffer->shared_buffer = clone;
    clone->shared_buffer = buffer;
    buffer->shared_fragments = fragment + 1;
    clone->shared_fragments = fragment + 1;

    return clone;
}


static zip_uint64_t buffer_find_fragment(const buffer_t *buffer, zip_uint64_t offset) {
    zip_uint64_t low, high, mid;

    if (buffer->nfragments == 0) {
        return 0;
    }

    low = 0;
    high = buffer->nfragments - 1;

    while (low < high) {
        mid = (high - low) / 2 + low;
        if (buffer->fragment_offsets[mid] > offset) {
            high = mid - 1;
        }
        else if (mid == buffer->nfragments || buffer->fragment_offsets[mid + 1] > offset) {
            return mid;
        }
        else {
            low = mid + 1;
        }
    }

    return low;
}


static void buffer_free(buffer_t *buffer) {
    zip_uint64_t i;

    if (buffer == NULL) {
        return;
    }

    if (buffer->shared_buffer != NULL) {
        buffer->shared_buffer->shared_buffer = NULL;
        buffer->shared_buffer->shared_fragments = 0;

        buffer->first_owned_fragment = ZIP_MAX(buffer->first_owned_fragment, buffer->shared_fragments);
    }

    for (i = buffer->first_owned_fragment; i < buffer->nfragments; i++) {
        free(buffer->fragments[i].data);
    }
    free(buffer->fragments);
    free(buffer->fragment_offsets);
    free(buffer);
}


static bool buffer_grow_fragments(buffer_t *buffer, zip_uint64_t capacity, zip_error_t *error) {
    zip_uint64_t additional_fragments;
    zip_uint64_t offset_capacity = buffer->fragments_capacity + 1;

    if (capacity <= buffer->fragments_capacity) {
        return true;
    }

    additional_fragments = capacity - buffer->fragments_capacity;

    if (!ZIP_REALLOC(buffer->fragments, buffer->fragments_capacity, additional_fragments, error)) {
        return false;
    }
    /* The size of both buffer->fragments and buffer->fragment_offsets is stored in buffer->fragments_capacity, so use a temporary capacity variable here for reallocating buffer->fragment_offsets. */
    if (!ZIP_REALLOC(buffer->fragment_offsets, offset_capacity, additional_fragments, error)) {
        buffer->fragments_capacity -= additional_fragments;
        return false;
    }

    return true;
}


static buffer_t *buffer_new(const zip_buffer_fragment_t *fragments, zip_uint64_t nfragments, int free_data, zip_error_t *error) {
    buffer_t *buffer;

    if ((buffer = malloc(sizeof(*buffer))) == NULL) {
        return NULL;
    }

    buffer->offset = 0;
    buffer->first_owned_fragment = 0;
    buffer->size = 0;
    buffer->fragments = NULL;
    buffer->fragment_offsets = NULL;
    buffer->nfragments = 0;
    buffer->fragments_capacity = 0;
    buffer->shared_buffer = NULL;
    buffer->shared_fragments = 0;

    if (nfragments == 0) {
        if ((buffer->fragment_offsets = malloc(sizeof(buffer->fragment_offsets[0]))) == NULL) {
            free(buffer);
            zip_error_set(error, ZIP_ER_MEMORY, 0);
            return NULL;
        }
        buffer->fragment_offsets[0] = 0;
    }
    else {
        zip_uint64_t i, j, offset;

        if (!buffer_grow_fragments(buffer, nfragments, NULL)) {
            zip_error_set(error, ZIP_ER_MEMORY, 0);
            buffer_free(buffer);
            return NULL;
        }

        offset = 0;
        for (i = 0, j = 0; i < nfragments; i++) {
            if (fragments[i].length == 0) {
                continue;
            }
            if (fragments[i].data == NULL) {
                zip_error_set(error, ZIP_ER_INVAL, 0);
                buffer_free(buffer);
                return NULL;
            }
            buffer->fragments[j].data = fragments[i].data;
            buffer->fragments[j].length = fragments[i].length;
            buffer->fragment_offsets[j] = offset;
            if (offset + fragments[i].length < offset) {
                zip_error_set(error, ZIP_ER_INVAL, 0);
                buffer_free(buffer);
                return NULL;
            }
            offset += fragments[i].length;
            j++;
        }
        buffer->nfragments = j;
        buffer->first_owned_fragment = free_data ? 0 : buffer->nfragments;
        buffer->fragment_offsets[buffer->nfragments] = offset;
        buffer->size = offset;
    }

    return buffer;
}

static zip_int64_t buffer_read(buffer_t *buffer, zip_uint8_t *data, zip_uint64_t length) {
    zip_uint64_t n, i, fragment_offset;

    length = ZIP_MIN(length, buffer->size - buffer->offset);

    if (length == 0) {
        return 0;
    }
    if (length > ZIP_INT64_MAX) {
        return -1;
    }

    i = buffer->current_fragment;
    fragment_offset = buffer->offset - buffer->fragment_offsets[i];
    n = 0;
    while (n < length) {
        zip_uint64_t left = ZIP_MIN(length - n, buffer->fragments[i].length - fragment_offset);
#if ZIP_UINT64_MAX > SIZE_MAX
        left = ZIP_MIN(left, SIZE_MAX);
#endif

        (void)memcpy_s(data + n, (size_t)left, buffer->fragments[i].data + fragment_offset, (size_t)left);

        if (left == buffer->fragments[i].length - fragment_offset) {
            i++;
        }
        n += left;
        fragment_offset = 0;
    }

    buffer->offset += n;
    buffer->current_fragment = i;
    return (zip_int64_t)n;
}


static int buffer_seek(buffer_t *buffer, void *data, zip_uint64_t len, zip_error_t *error) {
    zip_int64_t new_offset = zip_source_seek_compute_offset(buffer->offset, buffer->size, data, len, error);

    if (new_offset < 0) {
        return -1;
    }

    buffer->offset = (zip_uint64_t)new_offset;
    buffer->current_fragment = buffer_find_fragment(buffer, buffer->offset);
    return 0;
}


static zip_int64_t buffer_write(buffer_t *buffer, const zip_uint8_t *data, zip_uint64_t length, zip_error_t *error) {
    zip_uint64_t copied, i, fragment_offset, capacity;

    if (buffer->offset + length + WRITE_FRAGMENT_SIZE - 1 < length) {
        zip_error_set(error, ZIP_ER_INVAL, 0);
        return -1;
    }

    /* grow buffer if needed */
    capacity = buffer_capacity(buffer);
    if (buffer->offset + length > capacity) {
        zip_uint64_t needed_fragments = buffer->nfragments + (length - (capacity - buffer->offset) + WRITE_FRAGMENT_SIZE - 1) / WRITE_FRAGMENT_SIZE;

        if (needed_fragments > buffer->fragments_capacity) {
            zip_uint64_t new_capacity = buffer->fragments_capacity;

            if (new_capacity == 0) {
                new_capacity = 16;
            }
            while (new_capacity < needed_fragments) {
                new_capacity *= 2;
            }

            if (!buffer_grow_fragments(buffer, new_capacity, error)) {
                zip_error_set(error, ZIP_ER_MEMORY, 0);
                return -1;
            }
        }

        while (buffer->nfragments < needed_fragments) {
            if ((buffer->fragments[buffer->nfragments].data = malloc(WRITE_FRAGMENT_SIZE)) == NULL) {
                zip_error_set(error, ZIP_ER_MEMORY, 0);
                return -1;
            }
            buffer->fragments[buffer->nfragments].length = WRITE_FRAGMENT_SIZE;
            buffer->nfragments++;
            capacity += WRITE_FRAGMENT_SIZE;
            buffer->fragment_offsets[buffer->nfragments] = capacity;
        }
    }

    i = buffer->current_fragment;
    fragment_offset = buffer->offset - buffer->fragment_offsets[i];
    copied = 0;
    while (copied < length) {
        zip_uint64_t n = ZIP_MIN(ZIP_MIN(length - copied, buffer->fragments[i].length - fragment_offset), SIZE_MAX);
#if ZIP_UINT64_MAX > SIZE_MAX
        n = ZIP_MIN(n, SIZE_MAX);
#endif

        (void)memcpy_s(buffer->fragments[i].data + fragment_offset, (size_t)n, data + copied, (size_t)n);

        if (n == buffer->fragments[i].length - fragment_offset) {
            i++;
            fragment_offset = 0;
        }
        else {
            fragment_offset += n;
        }
        copied += n;
    }

    buffer->offset += copied;
    buffer->current_fragment = i;
    if (buffer->offset > buffer->size) {
        buffer->size = buffer->offset;
    }

    return (zip_int64_t)copied;
}

Coverage Report

Created: 2026-04-01 07:49

Line	Count	Source
1		/*
2		zip_source_buffer.c -- create zip data source from buffer
3		Copyright (C) 1999-2025 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		#ifndef WRITE_FRAGMENT_SIZE
40	0	#define WRITE_FRAGMENT_SIZE (64 * 1024)
41		#endif
42
43		struct buffer {
44		zip_buffer_fragment_t fragments; / fragments */
45		zip_uint64_t fragment_offsets; / offset of each fragment from start of buffer, nfragments+1 entries */
46		zip_uint64_t nfragments; /* number of allocated fragments */
47		zip_uint64_t fragments_capacity; /* size of fragments (number of pointers) */
48
49		zip_uint64_t first_owned_fragment; /* first fragment to free data from */
50
51		zip_uint64_t shared_fragments; /* number of shared fragments */
52		struct buffer shared_buffer; / buffer fragments are shared with */
53
54		zip_uint64_t size; /* size of buffer */
55		zip_uint64_t offset; /* current offset in buffer */
56		zip_uint64_t current_fragment; /* fragment current offset is in */
57		};
58
59		typedef struct buffer buffer_t;
60
61		struct read_data {
62		zip_error_t error;
63		time_t mtime;
64		zip_file_attributes_t attributes;
65		buffer_t *in;
66		buffer_t *out;
67		};
68
69	0	#define buffer_capacity(buffer) ((buffer)->fragment_offsets[(buffer)->nfragments])
70		#define buffer_size(buffer) ((buffer)->size)
71
72		static buffer_t buffer_clone(buffer_t buffer, zip_uint64_t length, zip_error_t *error);
73		static zip_uint64_t buffer_find_fragment(const buffer_t *buffer, zip_uint64_t offset);
74		static void buffer_free(buffer_t *buffer);
75		static bool buffer_grow_fragments(buffer_t buffer, zip_uint64_t capacity, zip_error_t error);
76		static buffer_t buffer_new(const zip_buffer_fragment_t fragments, zip_uint64_t nfragments, int free_data, zip_error_t *error);
77		static zip_int64_t buffer_read(buffer_t buffer, zip_uint8_t data, zip_uint64_t length);
78		static int buffer_seek(buffer_t buffer, void data, zip_uint64_t len, zip_error_t *error);
79		static zip_int64_t buffer_write(buffer_t buffer, const zip_uint8_t data, zip_uint64_t length, zip_error_t *);
80
81		static zip_int64_t read_data(void , void , zip_uint64_t, zip_source_cmd_t);
82
83		zip_source_t zip_source_buffer_with_attributes_create(const void data, zip_uint64_t len, int freep, zip_file_attributes_t attributes, zip_error_t error);
84		zip_source_t zip_source_buffer_fragment_with_attributes_create(const zip_buffer_fragment_t fragments, zip_uint64_t nfragments, int freep, zip_file_attributes_t attributes, zip_error_t error);
85
86
87	0	ZIP_EXTERN zip_source_t zip_source_buffer(zip_t za, const void *data, zip_uint64_t len, int freep) {
88	0	if (za == NULL) {
89	0	return NULL;
90	0	}
91
92	0	return zip_source_buffer_with_attributes_create(data, len, freep, NULL, &za->error);
93	0	}
94
95
96	0	ZIP_EXTERN zip_source_t zip_source_buffer_create(const void data, zip_uint64_t len, int freep, zip_error_t *error) {
97	0	return zip_source_buffer_with_attributes_create(data, len, freep, NULL, error);
98	0	}
99
100
101	0	zip_source_t zip_source_buffer_with_attributes_create(const void data, zip_uint64_t len, int freep, zip_file_attributes_t attributes, zip_error_t error) {
102	0	zip_buffer_fragment_t fragment;
103
104	0	if (data == NULL) {
105	0	if (len > 0) {
106	0	zip_error_set(error, ZIP_ER_INVAL, 0);
107	0	return NULL;
108	0	}
109
110	0	return zip_source_buffer_fragment_with_attributes_create(NULL, 0, freep, attributes, error);
111	0	}
112
113	0	fragment.data = (zip_uint8_t *)data;
114	0	fragment.length = len;
115
116	0	return zip_source_buffer_fragment_with_attributes_create(&fragment, 1, freep, attributes, error);
117	0	}
118
119
120	0	ZIP_EXTERN zip_source_t zip_source_buffer_fragment(zip_t za, const zip_buffer_fragment_t *fragments, zip_uint64_t nfragments, int freep) {
121	0	if (za == NULL) {
122	0	return NULL;
123	0	}
124
125	0	return zip_source_buffer_fragment_with_attributes_create(fragments, nfragments, freep, NULL, &za->error);
126	0	}
127
128
129	0	ZIP_EXTERN zip_source_t zip_source_buffer_fragment_create(const zip_buffer_fragment_t fragments, zip_uint64_t nfragments, int freep, zip_error_t *error) {
130	0	return zip_source_buffer_fragment_with_attributes_create(fragments, nfragments, freep, NULL, error);
131	0	}
132
133	0	zip_source_t zip_source_buffer_fragment_with_attributes_create(const zip_buffer_fragment_t fragments, zip_uint64_t nfragments, int freep, zip_file_attributes_t attributes, zip_error_t error) {
134	0	struct read_data *ctx;
135	0	zip_source_t *zs;
136	0	buffer_t *buffer;
137
138	0	if (fragments == NULL && nfragments > 0) {
139	0	zip_error_set(error, ZIP_ER_INVAL, 0);
140	0	return NULL;
141	0	}
142
143	0	if ((buffer = buffer_new(fragments, nfragments, freep, error)) == NULL) {
144	0	return NULL;
145	0	}
146
147	0	if ((ctx = (struct read_data )malloc(sizeof(ctx))) == NULL) {
148	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
149	0	buffer_free(buffer);
150	0	return NULL;
151	0	}
152
153	0	ctx->in = buffer;
154	0	ctx->out = NULL;
155	0	ctx->mtime = time(NULL);
156	0	if (attributes) {
157	0	(void)memcpy_s(&ctx->attributes, sizeof(ctx->attributes), attributes, sizeof(ctx->attributes));
158	0	}
159	0	else {
160	0	zip_file_attributes_init(&ctx->attributes);
161	0	}
162	0	zip_error_init(&ctx->error);
163
164	0	if ((zs = zip_source_function_create(read_data, ctx, error)) == NULL) {
165	0	buffer_free(ctx->in);
166	0	free(ctx);
167	0	return NULL;
168	0	}
169
170	0	return zs;
171	0	}
172
173
174	0	zip_source_t zip_source_buffer_with_attributes(zip_t za, const void data, zip_uint64_t len, int freep, zip_file_attributes_t attributes) {
175	0	return zip_source_buffer_with_attributes_create(data, len, freep, attributes, &za->error);
176	0	}
177
178	0	static zip_int64_t read_data(void state, void data, zip_uint64_t len, zip_source_cmd_t cmd) {
179	0	struct read_data ctx = (struct read_data )state;
180
181	0	switch (cmd) {
182	0	case ZIP_SOURCE_BEGIN_WRITE:
183	0	if ((ctx->out = buffer_new(NULL, 0, 0, &ctx->error)) == NULL) {
184	0	return -1;
185	0	}
186	0	ctx->out->offset = 0;
187	0	ctx->out->current_fragment = 0;
188	0	return 0;
189
190	0	case ZIP_SOURCE_BEGIN_WRITE_CLONING:
191	0	if ((ctx->out = buffer_clone(ctx->in, len, &ctx->error)) == NULL) {
192	0	return -1;
193	0	}
194	0	ctx->out->offset = len;
195	0	ctx->out->current_fragment = ctx->out->nfragments;
196	0	return 0;
197
198	0	case ZIP_SOURCE_CLOSE:
199	0	return 0;
200
201	0	case ZIP_SOURCE_COMMIT_WRITE:
202	0	buffer_free(ctx->in);
203	0	ctx->in = ctx->out;
204	0	ctx->out = NULL;
205	0	return 0;
206
207	0	case ZIP_SOURCE_ERROR:
208	0	return zip_error_to_data(&ctx->error, data, len);
209
210	0	case ZIP_SOURCE_FREE:
211	0	buffer_free(ctx->in);
212	0	buffer_free(ctx->out);
213	0	free(ctx);
214	0	return 0;
215
216	0	case ZIP_SOURCE_GET_FILE_ATTRIBUTES: {
217	0	if (len < sizeof(ctx->attributes)) {
218	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
219	0	return -1;
220	0	}
221
222	0	(void)memcpy_s(data, sizeof(ctx->attributes), &ctx->attributes, sizeof(ctx->attributes));
223
224	0	return sizeof(ctx->attributes);
225	0	}
226
227	0	case ZIP_SOURCE_OPEN:
228	0	ctx->in->offset = 0;
229	0	ctx->in->current_fragment = 0;
230	0	return 0;
231
232	0	case ZIP_SOURCE_READ:
233	0	if (len > ZIP_INT64_MAX) {
234	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
235	0	return -1;
236	0	}
237	0	return buffer_read(ctx->in, data, len);
238
239	0	case ZIP_SOURCE_REMOVE: {
240	0	buffer_t *empty = buffer_new(NULL, 0, 0, &ctx->error);
241	0	if (empty == NULL) {
242	0	return -1;
243	0	}
244
245	0	buffer_free(ctx->in);
246	0	ctx->in = empty;
247	0	return 0;
248	0	}
249
250	0	case ZIP_SOURCE_ROLLBACK_WRITE:
251	0	buffer_free(ctx->out);
252	0	ctx->out = NULL;
253	0	return 0;
254
255	0	case ZIP_SOURCE_SEEK:
256	0	return buffer_seek(ctx->in, data, len, &ctx->error);
257
258	0	case ZIP_SOURCE_SEEK_WRITE:
259	0	return buffer_seek(ctx->out, data, len, &ctx->error);
260
261	0	case ZIP_SOURCE_STAT: {
262	0	zip_stat_t *st;
263
264	0	if (len < sizeof(*st)) {
265	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
266	0	return -1;
267	0	}
268
269	0	st = (zip_stat_t *)data;
270
271	0	zip_stat_init(st);
272	0	st->mtime = ctx->mtime;
273	0	st->size = ctx->in->size;
274	0	st->comp_size = st->size;
275	0	st->comp_method = ZIP_CM_STORE;
276	0	st->encryption_method = ZIP_EM_NONE;
277	0	st->valid = ZIP_STAT_MTIME \| ZIP_STAT_SIZE \| ZIP_STAT_COMP_SIZE \| ZIP_STAT_COMP_METHOD \| ZIP_STAT_ENCRYPTION_METHOD;
278
279	0	return sizeof(*st);
280	0	}
281
282	0	case ZIP_SOURCE_SUPPORTS:
283	0	return zip_source_make_command_bitmap(ZIP_SOURCE_GET_FILE_ATTRIBUTES, ZIP_SOURCE_OPEN, ZIP_SOURCE_READ, ZIP_SOURCE_CLOSE, ZIP_SOURCE_STAT, ZIP_SOURCE_ERROR, ZIP_SOURCE_FREE, ZIP_SOURCE_SEEK, ZIP_SOURCE_TELL, ZIP_SOURCE_BEGIN_WRITE, ZIP_SOURCE_BEGIN_WRITE_CLONING, ZIP_SOURCE_COMMIT_WRITE, ZIP_SOURCE_REMOVE, ZIP_SOURCE_ROLLBACK_WRITE, ZIP_SOURCE_SEEK_WRITE, ZIP_SOURCE_TELL_WRITE, ZIP_SOURCE_WRITE, ZIP_SOURCE_SUPPORTS_REOPEN, -1);
284
285	0	case ZIP_SOURCE_TELL:
286	0	if (ctx->in->offset > ZIP_INT64_MAX) {
287	0	zip_error_set(&ctx->error, ZIP_ER_TELL, EOVERFLOW);
288	0	return -1;
289	0	}
290	0	return (zip_int64_t)ctx->in->offset;
291
292
293	0	case ZIP_SOURCE_TELL_WRITE:
294	0	if (ctx->out->offset > ZIP_INT64_MAX) {
295	0	zip_error_set(&ctx->error, ZIP_ER_TELL, EOVERFLOW);
296	0	return -1;
297	0	}
298	0	return (zip_int64_t)ctx->out->offset;
299
300	0	case ZIP_SOURCE_WRITE:
301	0	if (len > ZIP_INT64_MAX) {
302	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
303	0	return -1;
304	0	}
305	0	return buffer_write(ctx->out, data, len, &ctx->error);
306
307	0	default:
308	0	zip_error_set(&ctx->error, ZIP_ER_OPNOTSUPP, 0);
309	0	return -1;
310	0	}
311	0	}
312
313
314	0	static buffer_t buffer_clone(buffer_t buffer, zip_uint64_t offset, zip_error_t *error) {
315	0	zip_uint64_t fragment, fragment_offset, waste;
316	0	buffer_t *clone;
317
318	0	if (offset == 0) {
319	0	return buffer_new(NULL, 0, 1, error);
320	0	}
321
322	0	if (offset > buffer->size) {
323	0	zip_error_set(error, ZIP_ER_INVAL, 0);
324	0	return NULL;
325	0	}
326	0	if (buffer->shared_buffer != NULL) {
327	0	zip_error_set(error, ZIP_ER_INUSE, 0);
328	0	return NULL;
329	0	}
330
331	0	fragment = buffer_find_fragment(buffer, offset);
332	0	fragment_offset = offset - buffer->fragment_offsets[fragment];
333
334	0	if (fragment_offset == 0) {
335		/* We can't be at beginning of fragment zero if offset > 0. */
336	0	fragment--;
337	0	fragment_offset = buffer->fragments[fragment].length;
338	0	}
339
340		/* TODO: This should also consider the length of the fully shared fragments */
341	0	waste = buffer->fragments[fragment].length - fragment_offset;
342	0	if (waste > offset) {
343	0	zip_error_set(error, ZIP_ER_OPNOTSUPP, 0);
344	0	return NULL;
345	0	}
346
347	0	if ((clone = buffer_new(buffer->fragments, fragment + 1, 0, error)) == NULL) {
348	0	return NULL;
349	0	}
350
351	0	#ifndef __clang_analyzer__
352		/* clone->fragments can't be null, since it was created with at least one fragment */
353	0	clone->fragments[fragment].length = fragment_offset;
354	0	#endif
355	0	clone->fragment_offsets[clone->nfragments] = offset;
356	0	clone->size = offset;
357
358	0	clone->first_owned_fragment = ZIP_MIN(buffer->first_owned_fragment, clone->nfragments);
359
360	0	buffer->shared_buffer = clone;
361	0	clone->shared_buffer = buffer;
362	0	buffer->shared_fragments = fragment + 1;
363	0	clone->shared_fragments = fragment + 1;
364
365	0	return clone;
366	0	}
367
368
369	0	static zip_uint64_t buffer_find_fragment(const buffer_t *buffer, zip_uint64_t offset) {
370	0	zip_uint64_t low, high, mid;
371
372	0	if (buffer->nfragments == 0) {
373	0	return 0;
374	0	}
375
376	0	low = 0;
377	0	high = buffer->nfragments - 1;
378
379	0	while (low < high) {
380	0	mid = (high - low) / 2 + low;
381	0	if (buffer->fragment_offsets[mid] > offset) {
382	0	high = mid - 1;
383	0	}
384	0	else if (mid == buffer->nfragments \|\| buffer->fragment_offsets[mid + 1] > offset) {
385	0	return mid;
386	0	}
387	0	else {
388	0	low = mid + 1;
389	0	}
390	0	}
391
392	0	return low;
393	0	}
394
395
396	0	static void buffer_free(buffer_t *buffer) {
397	0	zip_uint64_t i;
398
399	0	if (buffer == NULL) {
400	0	return;
401	0	}
402
403	0	if (buffer->shared_buffer != NULL) {
404	0	buffer->shared_buffer->shared_buffer = NULL;
405	0	buffer->shared_buffer->shared_fragments = 0;
406
407	0	buffer->first_owned_fragment = ZIP_MAX(buffer->first_owned_fragment, buffer->shared_fragments);
408	0	}
409
410	0	for (i = buffer->first_owned_fragment; i < buffer->nfragments; i++) {
411	0	free(buffer->fragments[i].data);
412	0	}
413	0	free(buffer->fragments);
414	0	free(buffer->fragment_offsets);
415	0	free(buffer);
416	0	}
417
418
419	0	static bool buffer_grow_fragments(buffer_t buffer, zip_uint64_t capacity, zip_error_t error) {
420	0	zip_uint64_t additional_fragments;
421	0	zip_uint64_t offset_capacity = buffer->fragments_capacity + 1;
422
423	0	if (capacity <= buffer->fragments_capacity) {
424	0	return true;
425	0	}
426
427	0	additional_fragments = capacity - buffer->fragments_capacity;
428
429	0	if (!ZIP_REALLOC(buffer->fragments, buffer->fragments_capacity, additional_fragments, error)) {
430	0	return false;
431	0	}
432		/* The size of both buffer->fragments and buffer->fragment_offsets is stored in buffer->fragments_capacity, so use a temporary capacity variable here for reallocating buffer->fragment_offsets. */
433	0	if (!ZIP_REALLOC(buffer->fragment_offsets, offset_capacity, additional_fragments, error)) {
434	0	buffer->fragments_capacity -= additional_fragments;
435	0	return false;
436	0	}
437
438	0	return true;
439	0	}
440
441
442	0	static buffer_t buffer_new(const zip_buffer_fragment_t fragments, zip_uint64_t nfragments, int free_data, zip_error_t *error) {
443	0	buffer_t *buffer;
444
445	0	if ((buffer = malloc(sizeof(*buffer))) == NULL) {
446	0	return NULL;
447	0	}
448
449	0	buffer->offset = 0;
450	0	buffer->first_owned_fragment = 0;
451	0	buffer->size = 0;
452	0	buffer->fragments = NULL;
453	0	buffer->fragment_offsets = NULL;
454	0	buffer->nfragments = 0;
455	0	buffer->fragments_capacity = 0;
456	0	buffer->shared_buffer = NULL;
457	0	buffer->shared_fragments = 0;
458
459	0	if (nfragments == 0) {
460	0	if ((buffer->fragment_offsets = malloc(sizeof(buffer->fragment_offsets[0]))) == NULL) {
461	0	free(buffer);
462	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
463	0	return NULL;
464	0	}
465	0	buffer->fragment_offsets[0] = 0;
466	0	}
467	0	else {
468	0	zip_uint64_t i, j, offset;
469
470	0	if (!buffer_grow_fragments(buffer, nfragments, NULL)) {
471	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
472	0	buffer_free(buffer);
473	0	return NULL;
474	0	}
475
476	0	offset = 0;
477	0	for (i = 0, j = 0; i < nfragments; i++) {
478	0	if (fragments[i].length == 0) {
479	0	continue;
480	0	}
481	0	if (fragments[i].data == NULL) {
482	0	zip_error_set(error, ZIP_ER_INVAL, 0);
483	0	buffer_free(buffer);
484	0	return NULL;
485	0	}
486	0	buffer->fragments[j].data = fragments[i].data;
487	0	buffer->fragments[j].length = fragments[i].length;
488	0	buffer->fragment_offsets[j] = offset;
489	0	if (offset + fragments[i].length < offset) {
490	0	zip_error_set(error, ZIP_ER_INVAL, 0);
491	0	buffer_free(buffer);
492	0	return NULL;
493	0	}
494	0	offset += fragments[i].length;
495	0	j++;
496	0	}
497	0	buffer->nfragments = j;
498	0	buffer->first_owned_fragment = free_data ? 0 : buffer->nfragments;
499	0	buffer->fragment_offsets[buffer->nfragments] = offset;
500	0	buffer->size = offset;
501	0	}
502
503	0	return buffer;
504	0	}
505
506	0	static zip_int64_t buffer_read(buffer_t buffer, zip_uint8_t data, zip_uint64_t length) {
507	0	zip_uint64_t n, i, fragment_offset;
508
509	0	length = ZIP_MIN(length, buffer->size - buffer->offset);
510
511	0	if (length == 0) {
512	0	return 0;
513	0	}
514	0	if (length > ZIP_INT64_MAX) {
515	0	return -1;
516	0	}
517
518	0	i = buffer->current_fragment;
519	0	fragment_offset = buffer->offset - buffer->fragment_offsets[i];
520	0	n = 0;
521	0	while (n < length) {
522	0	zip_uint64_t left = ZIP_MIN(length - n, buffer->fragments[i].length - fragment_offset);
523		#if ZIP_UINT64_MAX > SIZE_MAX
524		left = ZIP_MIN(left, SIZE_MAX);
525		#endif
526
527	0	(void)memcpy_s(data + n, (size_t)left, buffer->fragments[i].data + fragment_offset, (size_t)left);
528
529	0	if (left == buffer->fragments[i].length - fragment_offset) {
530	0	i++;
531	0	}
532	0	n += left;
533	0	fragment_offset = 0;
534	0	}
535
536	0	buffer->offset += n;
537	0	buffer->current_fragment = i;
538	0	return (zip_int64_t)n;
539	0	}
540
541
542	0	static int buffer_seek(buffer_t buffer, void data, zip_uint64_t len, zip_error_t *error) {
543	0	zip_int64_t new_offset = zip_source_seek_compute_offset(buffer->offset, buffer->size, data, len, error);
544
545	0	if (new_offset < 0) {
546	0	return -1;
547	0	}
548
549	0	buffer->offset = (zip_uint64_t)new_offset;
550	0	buffer->current_fragment = buffer_find_fragment(buffer, buffer->offset);
551	0	return 0;
552	0	}
553
554
555	0	static zip_int64_t buffer_write(buffer_t buffer, const zip_uint8_t data, zip_uint64_t length, zip_error_t *error) {
556	0	zip_uint64_t copied, i, fragment_offset, capacity;
557
558	0	if (buffer->offset + length + WRITE_FRAGMENT_SIZE - 1 < length) {
559	0	zip_error_set(error, ZIP_ER_INVAL, 0);
560	0	return -1;
561	0	}
562
563		/* grow buffer if needed */
564	0	capacity = buffer_capacity(buffer);
565	0	if (buffer->offset + length > capacity) {
566	0	zip_uint64_t needed_fragments = buffer->nfragments + (length - (capacity - buffer->offset) + WRITE_FRAGMENT_SIZE - 1) / WRITE_FRAGMENT_SIZE;
567
568	0	if (needed_fragments > buffer->fragments_capacity) {
569	0	zip_uint64_t new_capacity = buffer->fragments_capacity;
570
571	0	if (new_capacity == 0) {
572	0	new_capacity = 16;
573	0	}
574	0	while (new_capacity < needed_fragments) {
575	0	new_capacity *= 2;
576	0	}
577
578	0	if (!buffer_grow_fragments(buffer, new_capacity, error)) {
579	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
580	0	return -1;
581	0	}
582	0	}
583
584	0	while (buffer->nfragments < needed_fragments) {
585	0	if ((buffer->fragments[buffer->nfragments].data = malloc(WRITE_FRAGMENT_SIZE)) == NULL) {
586	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
587	0	return -1;
588	0	}
589	0	buffer->fragments[buffer->nfragments].length = WRITE_FRAGMENT_SIZE;
590	0	buffer->nfragments++;
591	0	capacity += WRITE_FRAGMENT_SIZE;
592	0	buffer->fragment_offsets[buffer->nfragments] = capacity;
593	0	}
594	0	}
595
596	0	i = buffer->current_fragment;
597	0	fragment_offset = buffer->offset - buffer->fragment_offsets[i];
598	0	copied = 0;
599	0	while (copied < length) {
600	0	zip_uint64_t n = ZIP_MIN(ZIP_MIN(length - copied, buffer->fragments[i].length - fragment_offset), SIZE_MAX);
601		#if ZIP_UINT64_MAX > SIZE_MAX
602		n = ZIP_MIN(n, SIZE_MAX);
603		#endif
604
605	0	(void)memcpy_s(buffer->fragments[i].data + fragment_offset, (size_t)n, data + copied, (size_t)n);
606
607	0	if (n == buffer->fragments[i].length - fragment_offset) {
608	0	i++;
609	0	fragment_offset = 0;
610	0	}
611	0	else {
612	0	fragment_offset += n;
613	0	}
614	0	copied += n;
615	0	}
616
617	0	buffer->offset += copied;
618	0	buffer->current_fragment = i;
619	0	if (buffer->offset > buffer->size) {
620	0	buffer->size = buffer->offset;
621	0	}
622
623	0	return (zip_int64_t)copied;
624	0	}