/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 zip_int64_t buffer_at_eof(const buffer_t *buffer);
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_AT_EOF:
        return buffer_at_eof(ctx->in);

    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_AT_EOF, 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_at_eof(const buffer_t *buffer) {
    return buffer->offset == buffer->size;
}

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: 2026-07-25 07:06

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 zip_int64_t buffer_at_eof(const buffer_t *buffer);
73		static buffer_t buffer_clone(buffer_t buffer, zip_uint64_t length, zip_error_t *error);
74		static zip_uint64_t buffer_find_fragment(const buffer_t *buffer, zip_uint64_t offset);
75		static void buffer_free(buffer_t *buffer);
76		static bool buffer_grow_fragments(buffer_t buffer, zip_uint64_t capacity, zip_error_t error);
77		static buffer_t buffer_new(const zip_buffer_fragment_t fragments, zip_uint64_t nfragments, int free_data, zip_error_t *error);
78		static zip_int64_t buffer_read(buffer_t buffer, zip_uint8_t data, zip_uint64_t length);
79		static int buffer_seek(buffer_t buffer, void data, zip_uint64_t len, zip_error_t *error);
80		static zip_int64_t buffer_write(buffer_t buffer, const zip_uint8_t data, zip_uint64_t length, zip_error_t *);
81
82		static zip_int64_t read_data(void , void , zip_uint64_t, zip_source_cmd_t);
83
84		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);
85		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);
86
87
88	0	ZIP_EXTERN zip_source_t zip_source_buffer(zip_t za, const void *data, zip_uint64_t len, int freep) {
89	0	if (za == NULL) {
90	0	return NULL;
91	0	}
92
93	0	return zip_source_buffer_with_attributes_create(data, len, freep, NULL, &za->error);
94	0	}
95
96
97	0	ZIP_EXTERN zip_source_t zip_source_buffer_create(const void data, zip_uint64_t len, int freep, zip_error_t *error) {
98	0	return zip_source_buffer_with_attributes_create(data, len, freep, NULL, error);
99	0	}
100
101
102	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) {
103	0	zip_buffer_fragment_t fragment;
104
105	0	if (data == NULL) {
106	0	if (len > 0) {
107	0	zip_error_set(error, ZIP_ER_INVAL, 0);
108	0	return NULL;
109	0	}
110
111	0	return zip_source_buffer_fragment_with_attributes_create(NULL, 0, freep, attributes, error);
112	0	}
113
114	0	fragment.data = (zip_uint8_t *)data;
115	0	fragment.length = len;
116
117	0	return zip_source_buffer_fragment_with_attributes_create(&fragment, 1, freep, attributes, error);
118	0	}
119
120
121	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) {
122	0	if (za == NULL) {
123	0	return NULL;
124	0	}
125
126	0	return zip_source_buffer_fragment_with_attributes_create(fragments, nfragments, freep, NULL, &za->error);
127	0	}
128
129
130	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) {
131	0	return zip_source_buffer_fragment_with_attributes_create(fragments, nfragments, freep, NULL, error);
132	0	}
133
134	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) {
135	0	struct read_data *ctx;
136	0	zip_source_t *zs;
137	0	buffer_t *buffer;
138
139	0	if (fragments == NULL && nfragments > 0) {
140	0	zip_error_set(error, ZIP_ER_INVAL, 0);
141	0	return NULL;
142	0	}
143
144	0	if ((buffer = buffer_new(fragments, nfragments, freep, error)) == NULL) {
145	0	return NULL;
146	0	}
147
148	0	if ((ctx = (struct read_data )malloc(sizeof(ctx))) == NULL) {
149	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
150	0	buffer_free(buffer);
151	0	return NULL;
152	0	}
153
154	0	ctx->in = buffer;
155	0	ctx->out = NULL;
156	0	ctx->mtime = time(NULL);
157	0	if (attributes) {
158	0	(void)memcpy_s(&ctx->attributes, sizeof(ctx->attributes), attributes, sizeof(ctx->attributes));
159	0	}
160	0	else {
161	0	zip_file_attributes_init(&ctx->attributes);
162	0	}
163	0	zip_error_init(&ctx->error);
164
165	0	if ((zs = zip_source_function_create(read_data, ctx, error)) == NULL) {
166	0	buffer_free(ctx->in);
167	0	free(ctx);
168	0	return NULL;
169	0	}
170
171	0	return zs;
172	0	}
173
174
175	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) {
176	0	return zip_source_buffer_with_attributes_create(data, len, freep, attributes, &za->error);
177	0	}
178
179	0	static zip_int64_t read_data(void state, void data, zip_uint64_t len, zip_source_cmd_t cmd) {
180	0	struct read_data ctx = (struct read_data )state;
181
182	0	switch (cmd) {
183	0	case ZIP_SOURCE_AT_EOF:
184	0	return buffer_at_eof(ctx->in);
185
186	0	case ZIP_SOURCE_BEGIN_WRITE:
187	0	if ((ctx->out = buffer_new(NULL, 0, 0, &ctx->error)) == NULL) {
188	0	return -1;
189	0	}
190	0	ctx->out->offset = 0;
191	0	ctx->out->current_fragment = 0;
192	0	return 0;
193
194	0	case ZIP_SOURCE_BEGIN_WRITE_CLONING:
195	0	if ((ctx->out = buffer_clone(ctx->in, len, &ctx->error)) == NULL) {
196	0	return -1;
197	0	}
198	0	ctx->out->offset = len;
199	0	ctx->out->current_fragment = ctx->out->nfragments;
200	0	return 0;
201
202	0	case ZIP_SOURCE_CLOSE:
203	0	return 0;
204
205	0	case ZIP_SOURCE_COMMIT_WRITE:
206	0	buffer_free(ctx->in);
207	0	ctx->in = ctx->out;
208	0	ctx->out = NULL;
209	0	return 0;
210
211	0	case ZIP_SOURCE_ERROR:
212	0	return zip_error_to_data(&ctx->error, data, len);
213
214	0	case ZIP_SOURCE_FREE:
215	0	buffer_free(ctx->in);
216	0	buffer_free(ctx->out);
217	0	free(ctx);
218	0	return 0;
219
220	0	case ZIP_SOURCE_GET_FILE_ATTRIBUTES: {
221	0	if (len < sizeof(ctx->attributes)) {
222	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
223	0	return -1;
224	0	}
225
226	0	(void)memcpy_s(data, sizeof(ctx->attributes), &ctx->attributes, sizeof(ctx->attributes));
227
228	0	return sizeof(ctx->attributes);
229	0	}
230
231	0	case ZIP_SOURCE_OPEN:
232	0	ctx->in->offset = 0;
233	0	ctx->in->current_fragment = 0;
234	0	return 0;
235
236	0	case ZIP_SOURCE_READ:
237	0	if (len > ZIP_INT64_MAX) {
238	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
239	0	return -1;
240	0	}
241	0	return buffer_read(ctx->in, data, len);
242
243	0	case ZIP_SOURCE_REMOVE: {
244	0	buffer_t *empty = buffer_new(NULL, 0, 0, &ctx->error);
245	0	if (empty == NULL) {
246	0	return -1;
247	0	}
248
249	0	buffer_free(ctx->in);
250	0	ctx->in = empty;
251	0	return 0;
252	0	}
253
254	0	case ZIP_SOURCE_ROLLBACK_WRITE:
255	0	buffer_free(ctx->out);
256	0	ctx->out = NULL;
257	0	return 0;
258
259	0	case ZIP_SOURCE_SEEK:
260	0	return buffer_seek(ctx->in, data, len, &ctx->error);
261
262	0	case ZIP_SOURCE_SEEK_WRITE:
263	0	return buffer_seek(ctx->out, data, len, &ctx->error);
264
265	0	case ZIP_SOURCE_STAT: {
266	0	zip_stat_t *st;
267
268	0	if (len < sizeof(*st)) {
269	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
270	0	return -1;
271	0	}
272
273	0	st = (zip_stat_t *)data;
274
275	0	zip_stat_init(st);
276	0	st->mtime = ctx->mtime;
277	0	st->size = ctx->in->size;
278	0	st->comp_size = st->size;
279	0	st->comp_method = ZIP_CM_STORE;
280	0	st->encryption_method = ZIP_EM_NONE;
281	0	st->valid = ZIP_STAT_MTIME \| ZIP_STAT_SIZE \| ZIP_STAT_COMP_SIZE \| ZIP_STAT_COMP_METHOD \| ZIP_STAT_ENCRYPTION_METHOD;
282
283	0	return sizeof(*st);
284	0	}
285
286	0	case ZIP_SOURCE_SUPPORTS:
287	0	return zip_source_make_command_bitmap(ZIP_SOURCE_AT_EOF, 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);
288
289	0	case ZIP_SOURCE_TELL:
290	0	if (ctx->in->offset > ZIP_INT64_MAX) {
291	0	zip_error_set(&ctx->error, ZIP_ER_TELL, EOVERFLOW);
292	0	return -1;
293	0	}
294	0	return (zip_int64_t)ctx->in->offset;
295
296
297	0	case ZIP_SOURCE_TELL_WRITE:
298	0	if (ctx->out->offset > ZIP_INT64_MAX) {
299	0	zip_error_set(&ctx->error, ZIP_ER_TELL, EOVERFLOW);
300	0	return -1;
301	0	}
302	0	return (zip_int64_t)ctx->out->offset;
303
304	0	case ZIP_SOURCE_WRITE:
305	0	if (len > ZIP_INT64_MAX) {
306	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
307	0	return -1;
308	0	}
309	0	return buffer_write(ctx->out, data, len, &ctx->error);
310
311	0	default:
312	0	zip_error_set(&ctx->error, ZIP_ER_OPNOTSUPP, 0);
313	0	return -1;
314	0	}
315	0	}
316
317
318	0	static buffer_t buffer_clone(buffer_t buffer, zip_uint64_t offset, zip_error_t *error) {
319	0	zip_uint64_t fragment, fragment_offset, waste;
320	0	buffer_t *clone;
321
322	0	if (offset == 0) {
323	0	return buffer_new(NULL, 0, 1, error);
324	0	}
325
326	0	if (offset > buffer->size) {
327	0	zip_error_set(error, ZIP_ER_INVAL, 0);
328	0	return NULL;
329	0	}
330	0	if (buffer->shared_buffer != NULL) {
331	0	zip_error_set(error, ZIP_ER_INUSE, 0);
332	0	return NULL;
333	0	}
334
335	0	fragment = buffer_find_fragment(buffer, offset);
336	0	fragment_offset = offset - buffer->fragment_offsets[fragment];
337
338	0	if (fragment_offset == 0) {
339		/* We can't be at beginning of fragment zero if offset > 0. */
340	0	fragment--;
341	0	fragment_offset = buffer->fragments[fragment].length;
342	0	}
343
344		/* TODO: This should also consider the length of the fully shared fragments */
345	0	waste = buffer->fragments[fragment].length - fragment_offset;
346	0	if (waste > offset) {
347	0	zip_error_set(error, ZIP_ER_OPNOTSUPP, 0);
348	0	return NULL;
349	0	}
350
351	0	if ((clone = buffer_new(buffer->fragments, fragment + 1, 0, error)) == NULL) {
352	0	return NULL;
353	0	}
354
355	0	#ifndef __clang_analyzer__
356		/* clone->fragments can't be null, since it was created with at least one fragment */
357	0	clone->fragments[fragment].length = fragment_offset;
358	0	#endif
359	0	clone->fragment_offsets[clone->nfragments] = offset;
360	0	clone->size = offset;
361
362	0	clone->first_owned_fragment = ZIP_MIN(buffer->first_owned_fragment, clone->nfragments);
363
364	0	buffer->shared_buffer = clone;
365	0	clone->shared_buffer = buffer;
366	0	buffer->shared_fragments = fragment + 1;
367	0	clone->shared_fragments = fragment + 1;
368
369	0	return clone;
370	0	}
371
372
373	0	static zip_uint64_t buffer_find_fragment(const buffer_t *buffer, zip_uint64_t offset) {
374	0	zip_uint64_t low, high, mid;
375
376	0	if (buffer->nfragments == 0) {
377	0	return 0;
378	0	}
379
380	0	low = 0;
381	0	high = buffer->nfragments - 1;
382
383	0	while (low < high) {
384	0	mid = (high - low) / 2 + low;
385	0	if (buffer->fragment_offsets[mid] > offset) {
386	0	high = mid - 1;
387	0	}
388	0	else if (mid == buffer->nfragments \|\| buffer->fragment_offsets[mid + 1] > offset) {
389	0	return mid;
390	0	}
391	0	else {
392	0	low = mid + 1;
393	0	}
394	0	}
395
396	0	return low;
397	0	}
398
399
400	0	static void buffer_free(buffer_t *buffer) {
401	0	zip_uint64_t i;
402
403	0	if (buffer == NULL) {
404	0	return;
405	0	}
406
407	0	if (buffer->shared_buffer != NULL) {
408	0	buffer->shared_buffer->shared_buffer = NULL;
409	0	buffer->shared_buffer->shared_fragments = 0;
410
411	0	buffer->first_owned_fragment = ZIP_MAX(buffer->first_owned_fragment, buffer->shared_fragments);
412	0	}
413
414	0	for (i = buffer->first_owned_fragment; i < buffer->nfragments; i++) {
415	0	free(buffer->fragments[i].data);
416	0	}
417	0	free(buffer->fragments);
418	0	free(buffer->fragment_offsets);
419	0	free(buffer);
420	0	}
421
422
423	0	static bool buffer_grow_fragments(buffer_t buffer, zip_uint64_t capacity, zip_error_t error) {
424	0	zip_uint64_t additional_fragments;
425	0	zip_uint64_t offset_capacity = buffer->fragments_capacity + 1;
426
427	0	if (capacity <= buffer->fragments_capacity) {
428	0	return true;
429	0	}
430
431	0	additional_fragments = capacity - buffer->fragments_capacity;
432
433	0	if (!ZIP_REALLOC(buffer->fragments, buffer->fragments_capacity, additional_fragments, error)) {
434	0	return false;
435	0	}
436		/* 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. */
437	0	if (!ZIP_REALLOC(buffer->fragment_offsets, offset_capacity, additional_fragments, error)) {
438	0	buffer->fragments_capacity -= additional_fragments;
439	0	return false;
440	0	}
441
442	0	return true;
443	0	}
444
445
446	0	static buffer_t buffer_new(const zip_buffer_fragment_t fragments, zip_uint64_t nfragments, int free_data, zip_error_t *error) {
447	0	buffer_t *buffer;
448
449	0	if ((buffer = malloc(sizeof(*buffer))) == NULL) {
450	0	return NULL;
451	0	}
452
453	0	buffer->offset = 0;
454	0	buffer->first_owned_fragment = 0;
455	0	buffer->size = 0;
456	0	buffer->fragments = NULL;
457	0	buffer->fragment_offsets = NULL;
458	0	buffer->nfragments = 0;
459	0	buffer->fragments_capacity = 0;
460	0	buffer->shared_buffer = NULL;
461	0	buffer->shared_fragments = 0;
462
463	0	if (nfragments == 0) {
464	0	if ((buffer->fragment_offsets = malloc(sizeof(buffer->fragment_offsets[0]))) == NULL) {
465	0	free(buffer);
466	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
467	0	return NULL;
468	0	}
469	0	buffer->fragment_offsets[0] = 0;
470	0	}
471	0	else {
472	0	zip_uint64_t i, j, offset;
473
474	0	if (!buffer_grow_fragments(buffer, nfragments, NULL)) {
475	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
476	0	buffer_free(buffer);
477	0	return NULL;
478	0	}
479
480	0	offset = 0;
481	0	for (i = 0, j = 0; i < nfragments; i++) {
482	0	if (fragments[i].length == 0) {
483	0	continue;
484	0	}
485	0	if (fragments[i].data == NULL) {
486	0	zip_error_set(error, ZIP_ER_INVAL, 0);
487	0	buffer_free(buffer);
488	0	return NULL;
489	0	}
490	0	buffer->fragments[j].data = fragments[i].data;
491	0	buffer->fragments[j].length = fragments[i].length;
492	0	buffer->fragment_offsets[j] = offset;
493	0	if (offset + fragments[i].length < offset) {
494	0	zip_error_set(error, ZIP_ER_INVAL, 0);
495	0	buffer_free(buffer);
496	0	return NULL;
497	0	}
498	0	offset += fragments[i].length;
499	0	j++;
500	0	}
501	0	buffer->nfragments = j;
502	0	buffer->first_owned_fragment = free_data ? 0 : buffer->nfragments;
503	0	buffer->fragment_offsets[buffer->nfragments] = offset;
504	0	buffer->size = offset;
505	0	}
506
507	0	return buffer;
508	0	}
509
510	0	static zip_int64_t buffer_at_eof(const buffer_t *buffer) {
511	0	return buffer->offset == buffer->size;
512	0	}
513
514	0	static zip_int64_t buffer_read(buffer_t buffer, zip_uint8_t data, zip_uint64_t length) {
515	0	zip_uint64_t n, i, fragment_offset;
516
517	0	length = ZIP_MIN(length, buffer->size - buffer->offset);
518
519	0	if (length == 0) {
520	0	return 0;
521	0	}
522	0	if (length > ZIP_INT64_MAX) {
523	0	return -1;
524	0	}
525
526	0	i = buffer->current_fragment;
527	0	fragment_offset = buffer->offset - buffer->fragment_offsets[i];
528	0	n = 0;
529	0	while (n < length) {
530	0	zip_uint64_t left = ZIP_MIN(length - n, buffer->fragments[i].length - fragment_offset);
531		#if ZIP_UINT64_MAX > SIZE_MAX
532		left = ZIP_MIN(left, SIZE_MAX);
533		#endif
534
535	0	(void)memcpy_s(data + n, (size_t)left, buffer->fragments[i].data + fragment_offset, (size_t)left);
536
537	0	if (left == buffer->fragments[i].length - fragment_offset) {
538	0	i++;
539	0	}
540	0	n += left;
541	0	fragment_offset = 0;
542	0	}
543
544	0	buffer->offset += n;
545	0	buffer->current_fragment = i;
546	0	return (zip_int64_t)n;
547	0	}
548
549
550	0	static int buffer_seek(buffer_t buffer, void data, zip_uint64_t len, zip_error_t *error) {
551	0	zip_int64_t new_offset = zip_source_seek_compute_offset(buffer->offset, buffer->size, data, len, error);
552
553	0	if (new_offset < 0) {
554	0	return -1;
555	0	}
556
557	0	buffer->offset = (zip_uint64_t)new_offset;
558	0	buffer->current_fragment = buffer_find_fragment(buffer, buffer->offset);
559	0	return 0;
560	0	}
561
562
563	0	static zip_int64_t buffer_write(buffer_t buffer, const zip_uint8_t data, zip_uint64_t length, zip_error_t *error) {
564	0	zip_uint64_t copied, i, fragment_offset, capacity;
565
566	0	if (buffer->offset + length + WRITE_FRAGMENT_SIZE - 1 < length) {
567	0	zip_error_set(error, ZIP_ER_INVAL, 0);
568	0	return -1;
569	0	}
570
571		/* grow buffer if needed */
572	0	capacity = buffer_capacity(buffer);
573	0	if (buffer->offset + length > capacity) {
574	0	zip_uint64_t needed_fragments = buffer->nfragments + (length - (capacity - buffer->offset) + WRITE_FRAGMENT_SIZE - 1) / WRITE_FRAGMENT_SIZE;
575
576	0	if (needed_fragments > buffer->fragments_capacity) {
577	0	zip_uint64_t new_capacity = buffer->fragments_capacity;
578
579	0	if (new_capacity == 0) {
580	0	new_capacity = 16;
581	0	}
582	0	while (new_capacity < needed_fragments) {
583	0	new_capacity *= 2;
584	0	}
585
586	0	if (!buffer_grow_fragments(buffer, new_capacity, error)) {
587	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
588	0	return -1;
589	0	}
590	0	}
591
592	0	while (buffer->nfragments < needed_fragments) {
593	0	if ((buffer->fragments[buffer->nfragments].data = malloc(WRITE_FRAGMENT_SIZE)) == NULL) {
594	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
595	0	return -1;
596	0	}
597	0	buffer->fragments[buffer->nfragments].length = WRITE_FRAGMENT_SIZE;
598	0	buffer->nfragments++;
599	0	capacity += WRITE_FRAGMENT_SIZE;
600	0	buffer->fragment_offsets[buffer->nfragments] = capacity;
601	0	}
602	0	}
603
604	0	i = buffer->current_fragment;
605	0	fragment_offset = buffer->offset - buffer->fragment_offsets[i];
606	0	copied = 0;
607	0	while (copied < length) {
608	0	zip_uint64_t n = ZIP_MIN(ZIP_MIN(length - copied, buffer->fragments[i].length - fragment_offset), SIZE_MAX);
609		#if ZIP_UINT64_MAX > SIZE_MAX
610		n = ZIP_MIN(n, SIZE_MAX);
611		#endif
612
613	0	(void)memcpy_s(buffer->fragments[i].data + fragment_offset, (size_t)n, data + copied, (size_t)n);
614
615	0	if (n == buffer->fragments[i].length - fragment_offset) {
616	0	i++;
617	0	fragment_offset = 0;
618	0	}
619	0	else {
620	0	fragment_offset += n;
621	0	}
622	0	copied += n;
623	0	}
624
625	0	buffer->offset += copied;
626	0	buffer->current_fragment = i;
627	0	if (buffer->offset > buffer->size) {
628	0	buffer->size = buffer->offset;
629	0	}
630
631	0	return (zip_int64_t)copied;
632	0	}