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/*
* Copyright (C) the libgit2 contributors. All rights reserved.
*
* This file is part of libgit2, distributed under the GNU GPL v2 with
* a Linking Exception. For full terms see the included COPYING file.
*/
#include <zlib.h>
#include "zstream.h"
#include "buffer.h"
#define ZSTREAM_BUFFER_SIZE (1024 * 1024)
#define ZSTREAM_BUFFER_MIN_EXTRA 8
static int zstream_seterr(git_zstream *zs)
{
if (zs->zerr == Z_OK || zs->zerr == Z_STREAM_END)
return 0;
if (zs->zerr == Z_MEM_ERROR)
giterr_set_oom();
else if (zs->z.msg)
giterr_set(GITERR_ZLIB, zs->z.msg);
else
giterr_set(GITERR_ZLIB, "Unknown compression error");
return -1;
}
int git_zstream_init(git_zstream *zstream)
{
zstream->zerr = deflateInit(&zstream->z, Z_DEFAULT_COMPRESSION);
return zstream_seterr(zstream);
}
void git_zstream_free(git_zstream *zstream)
{
deflateEnd(&zstream->z);
}
void git_zstream_reset(git_zstream *zstream)
{
deflateReset(&zstream->z);
zstream->in = NULL;
zstream->in_len = 0;
zstream->zerr = Z_STREAM_END;
}
int git_zstream_set_input(git_zstream *zstream, const void *in, size_t in_len)
{
zstream->in = in;
zstream->in_len = in_len;
zstream->zerr = Z_OK;
return 0;
}
bool git_zstream_done(git_zstream *zstream)
{
return (!zstream->in_len && zstream->zerr == Z_STREAM_END);
}
size_t git_zstream_suggest_output_len(git_zstream *zstream)
{
if (zstream->in_len > ZSTREAM_BUFFER_SIZE)
return ZSTREAM_BUFFER_SIZE;
else if (zstream->in_len > ZSTREAM_BUFFER_MIN_EXTRA)
return zstream->in_len;
else
return ZSTREAM_BUFFER_MIN_EXTRA;
}
int git_zstream_get_output(void *out, size_t *out_len, git_zstream *zstream)
{
int zflush = Z_FINISH;
size_t out_remain = *out_len;
while (out_remain > 0 && zstream->zerr != Z_STREAM_END) {
size_t out_queued, in_queued, out_used, in_used;
/* set up in data */
zstream->z.next_in = (Bytef *)zstream->in;
zstream->z.avail_in = (uInt)zstream->in_len;
if ((size_t)zstream->z.avail_in != zstream->in_len) {
zstream->z.avail_in = INT_MAX;
zflush = Z_NO_FLUSH;
} else {
zflush = Z_FINISH;
}
in_queued = (size_t)zstream->z.avail_in;
/* set up out data */
zstream->z.next_out = out;
zstream->z.avail_out = (uInt)out_remain;
if ((size_t)zstream->z.avail_out != out_remain)
zstream->z.avail_out = INT_MAX;
out_queued = (size_t)zstream->z.avail_out;
/* compress next chunk */
zstream->zerr = deflate(&zstream->z, zflush);
if (zstream->zerr == Z_STREAM_ERROR)
return zstream_seterr(zstream);
out_used = (out_queued - zstream->z.avail_out);
out_remain -= out_used;
out = ((char *)out) + out_used;
in_used = (in_queued - zstream->z.avail_in);
zstream->in_len -= in_used;
zstream->in += in_used;
}
/* either we finished the input or we did not flush the data */
assert(zstream->in_len > 0 || zflush == Z_FINISH);
/* set out_size to number of bytes actually written to output */
*out_len = *out_len - out_remain;
return 0;
}
int git_zstream_deflatebuf(git_buf *out, const void *in, size_t in_len)
{
git_zstream zs = GIT_ZSTREAM_INIT;
int error = 0;
if ((error = git_zstream_init(&zs)) < 0)
return error;
if ((error = git_zstream_set_input(&zs, in, in_len)) < 0)
goto done;
while (!git_zstream_done(&zs)) {
size_t step = git_zstream_suggest_output_len(&zs), written;
if ((error = git_buf_grow(out, out->asize + step)) < 0)
goto done;
written = out->asize - out->size;
if ((error = git_zstream_get_output(
out->ptr + out->size, &written, &zs)) < 0)
goto done;
out->size += written;
}
/* NULL terminate for consistency if possible */
if (out->size < out->asize)
out->ptr[out->size] = '\0';
done:
git_zstream_free(&zs);
return error;
}
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