diff options
Diffstat (limited to 'src/util/zstream.c')
| -rw-r--r-- | src/util/zstream.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/src/util/zstream.c b/src/util/zstream.c new file mode 100644 index 000000000..cb8b125ed --- /dev/null +++ b/src/util/zstream.c @@ -0,0 +1,210 @@ +/* + * 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); +} |