src/zstream.c

   1 /*
   2  * Copyright (C) the libgit2 contributors. All rights reserved.
   3  *
   4  * This file is part of libgit2, distributed under the GNU GPL v2 with
   5  * a Linking Exception. For full terms see the included COPYING file.
   6  */
   7
   8 #include <zlib.h>
   9
  10 #include "zstream.h"
  11 #include "buffer.h"
  12
  13 #define BUFFER_SIZE (1024 * 1024)
  14
  15 static int zstream_seterr(int zerr, git_zstream *zstream)
  16 {
  17         if (zerr == Z_MEM_ERROR)
  18                 giterr_set_oom();
  19         else if (zstream->msg)
  20                 giterr_set(GITERR_ZLIB, zstream->msg);
  21         else
  22                 giterr_set(GITERR_ZLIB, "Unknown compression error");
  23
  24         return -1;
  25 }
  26
  27 int git_zstream_init(git_zstream *zstream)
  28 {
  29         int zerr;
  30
  31         if ((zerr = deflateInit(zstream, Z_DEFAULT_COMPRESSION)) != Z_OK)
  32                 return zstream_seterr(zerr, zstream);
  33
  34         return 0;
  35 }
  36
  37 ssize_t git_zstream_deflate(void *out, size_t out_len, git_zstream *zstream, const void *in, size_t in_len)
  38 {
  39         int zerr;
  40
  41         if ((ssize_t)out_len < 0)
  42                 out_len = INT_MAX;
  43
  44         zstream->next_in = (Bytef *)in;
  45         zstream->avail_in = in_len;
  46         zstream->next_out = out;
  47         zstream->avail_out = out_len;
  48
  49         if ((zerr = deflate(zstream, Z_FINISH)) == Z_STREAM_ERROR)
  50                 return zstream_seterr(zerr, zstream);
  51
  52         return (out_len - zstream->avail_out);
  53 }
  54
  55 void git_zstream_reset(git_zstream *zstream)
  56 {
  57         deflateReset(zstream);
  58 }
  59
  60 void git_zstream_free(git_zstream *zstream)
  61 {
  62         deflateEnd(zstream);
  63 }
  64
  65 int git_zstream_deflatebuf(git_buf *out, const void *in, size_t in_len)
  66 {
  67         git_zstream zstream = GIT_ZSTREAM_INIT;
  68         size_t out_len;
  69         ssize_t written;
  70         int error = 0;
  71
  72         if ((error = git_zstream_init(&zstream)) < 0)
  73                 return error;
  74
  75         do {
  76                 if (out->asize - out->size < BUFFER_SIZE)
  77                         git_buf_grow(out, out->asize + BUFFER_SIZE);
  78
  79                 out_len = out->asize - out->size;
  80
  81                 if ((written = git_zstream_deflate(out->ptr + out->size, out_len, &zstream, in, in_len)) <= 0)
  82                         break;
  83
  84                 in = (char *)in + written;
  85                 in_len -= written;
  86                 out->size += written;
  87         } while (written > 0);
  88
  89         if (written < 0)
  90                 error = written;
  91
  92         git_zstream_free(&zstream);
  93         return error;
  94 }