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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 "zstream.h"
#include <zlib.h>
#include "str.h"
#define ZSTREAM_BUFFER_SIZE (1024 * 1024)
#define ZSTREAM_BUFFER_MIN_EXTRA 8
GIT_INLINE(int) zstream_seterr(git_zstream *zs)
{
switch (zs->zerr) {
case Z_OK:
case Z_STREAM_END:
case Z_BUF_ERROR: /* not fatal; we retry with a larger buffer */
return 0;
case Z_MEM_ERROR:
git_error_set_oom();
break;
default:
if (zs->z.msg)
git_error_set_str(GIT_ERROR_ZLIB, zs->z.msg);
else
git_error_set(GIT_ERROR_ZLIB, "unknown compression error");
}
return -1;
}
int git_zstream_init(git_zstream *zstream, git_zstream_t type)
{
zstream->type = type;
if (zstream->type == GIT_ZSTREAM_INFLATE)
zstream->zerr = inflateInit(&zstream->z);
else
zstream->zerr = deflateInit(&zstream->z, Z_DEFAULT_COMPRESSION);
return zstream_seterr(zstream);
}
void git_zstream_free(git_zstream *zstream)
{
if (zstream->type == GIT_ZSTREAM_INFLATE)
inflateEnd(&zstream->z);
else
deflateEnd(&zstream->z);
}
void git_zstream_reset(git_zstream *zstream)
{
if (zstream->type == GIT_ZSTREAM_INFLATE)
inflateReset(&zstream->z);
else
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);
}
bool git_zstream_eos(git_zstream *zstream)
{
return 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_chunk(
void *out, size_t *out_len, git_zstream *zstream)
{
size_t in_queued, in_used, out_queued;
/* set up input data */
zstream->z.next_in = (Bytef *)zstream->in;
/* feed as much data to zlib as it can consume, at most UINT_MAX */
if (zstream->in_len > UINT_MAX) {
zstream->z.avail_in = UINT_MAX;
zstream->flush = Z_NO_FLUSH;
} else {
zstream->z.avail_in = (uInt)zstream->in_len;
zstream->flush = Z_FINISH;
}
in_queued = (size_t)zstream->z.avail_in;
/* set up output data */
zstream->z.next_out = out;
zstream->z.avail_out = (uInt)*out_len;
if ((size_t)zstream->z.avail_out != *out_len)
zstream->z.avail_out = UINT_MAX;
out_queued = (size_t)zstream->z.avail_out;
/* compress next chunk */
if (zstream->type == GIT_ZSTREAM_INFLATE)
zstream->zerr = inflate(&zstream->z, zstream->flush);
else
zstream->zerr = deflate(&zstream->z, zstream->flush);
if (zstream_seterr(zstream))
return -1;
in_used = (in_queued - zstream->z.avail_in);
zstream->in_len -= in_used;
zstream->in += in_used;
*out_len = (out_queued - zstream->z.avail_out);
return 0;
}
int git_zstream_get_output(void *out, size_t *out_len, git_zstream *zstream)
{
size_t out_remain = *out_len;
if (zstream->in_len && zstream->zerr == Z_STREAM_END) {
git_error_set(GIT_ERROR_ZLIB, "zlib input had trailing garbage");
return -1;
}
while (out_remain > 0 && zstream->zerr != Z_STREAM_END) {
size_t out_written = out_remain;
if (git_zstream_get_output_chunk(out, &out_written, zstream) < 0)
return -1;
out_remain -= out_written;
out = ((char *)out) + out_written;
}
/* either we finished the input or we did not flush the data */
GIT_ASSERT(zstream->in_len > 0 || zstream->flush == Z_FINISH);
/* set out_size to number of bytes actually written to output */
*out_len = *out_len - out_remain;
return 0;
}
static int zstream_buf(git_str *out, const void *in, size_t in_len, git_zstream_t type)
{
git_zstream zs = GIT_ZSTREAM_INIT;
int error = 0;
if ((error = git_zstream_init(&zs, type)) < 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_str_grow_by(out, 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;
}
int git_zstream_deflatebuf(git_str *out, const void *in, size_t in_len)
{
return zstream_buf(out, in, in_len, GIT_ZSTREAM_DEFLATE);
}
int git_zstream_inflatebuf(git_str *out, const void *in, size_t in_len)
{
return zstream_buf(out, in, in_len, GIT_ZSTREAM_INFLATE);
}
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