Update draft release notes to 1.7.9
[gitweb.git] / zlib.c
diff --git a/zlib.c b/zlib.c
index c4d58da4e9050c6330ff145914cc379f0600f703..2b2c0c780e3fca6217c688298053a01aad724505 100644 (file)
--- a/zlib.c
+++ b/zlib.c
  */
 #include "cache.h"
 
-void git_inflate_init(z_streamp strm)
+static const char *zerr_to_string(int status)
 {
-       const char *err;
+       switch (status) {
+       case Z_MEM_ERROR:
+               return "out of memory";
+       case Z_VERSION_ERROR:
+               return "wrong version";
+       case Z_NEED_DICT:
+               return "needs dictionary";
+       case Z_DATA_ERROR:
+               return "data stream error";
+       case Z_STREAM_ERROR:
+               return "stream consistency error";
+       default:
+               return "unknown error";
+       }
+}
 
-       switch (inflateInit(strm)) {
-       case Z_OK:
+/*
+ * avail_in and avail_out in zlib are counted in uInt, which typically
+ * limits the size of the buffer we can use to 4GB when interacting
+ * with zlib in a single call to inflate/deflate.
+ */
+/* #define ZLIB_BUF_MAX ((uInt)-1) */
+#define ZLIB_BUF_MAX ((uInt) 1024 * 1024 * 1024) /* 1GB */
+static inline uInt zlib_buf_cap(unsigned long len)
+{
+       return (ZLIB_BUF_MAX < len) ? ZLIB_BUF_MAX : len;
+}
+
+static void zlib_pre_call(git_zstream *s)
+{
+       s->z.next_in = s->next_in;
+       s->z.next_out = s->next_out;
+       s->z.total_in = s->total_in;
+       s->z.total_out = s->total_out;
+       s->z.avail_in = zlib_buf_cap(s->avail_in);
+       s->z.avail_out = zlib_buf_cap(s->avail_out);
+}
+
+static void zlib_post_call(git_zstream *s)
+{
+       unsigned long bytes_consumed;
+       unsigned long bytes_produced;
+
+       bytes_consumed = s->z.next_in - s->next_in;
+       bytes_produced = s->z.next_out - s->next_out;
+       if (s->z.total_out != s->total_out + bytes_produced)
+               die("BUG: total_out mismatch");
+       if (s->z.total_in != s->total_in + bytes_consumed)
+               die("BUG: total_in mismatch");
+
+       s->total_out = s->z.total_out;
+       s->total_in = s->z.total_in;
+       s->next_in = s->z.next_in;
+       s->next_out = s->z.next_out;
+       s->avail_in -= bytes_consumed;
+       s->avail_out -= bytes_produced;
+}
+
+void git_inflate_init(git_zstream *strm)
+{
+       int status;
+
+       zlib_pre_call(strm);
+       status = inflateInit(&strm->z);
+       zlib_post_call(strm);
+       if (status == Z_OK)
                return;
+       die("inflateInit: %s (%s)", zerr_to_string(status),
+           strm->z.msg ? strm->z.msg : "no message");
+}
 
-       case Z_MEM_ERROR:
-               err = "out of memory";
-               break;
-       case Z_VERSION_ERROR:
-               err = "wrong version";
+void git_inflate_init_gzip_only(git_zstream *strm)
+{
+       /*
+        * Use default 15 bits, +16 is to accept only gzip and to
+        * yield Z_DATA_ERROR when fed zlib format.
+        */
+       const int windowBits = 15 + 16;
+       int status;
+
+       zlib_pre_call(strm);
+       status = inflateInit2(&strm->z, windowBits);
+       zlib_post_call(strm);
+       if (status == Z_OK)
+               return;
+       die("inflateInit2: %s (%s)", zerr_to_string(status),
+           strm->z.msg ? strm->z.msg : "no message");
+}
+
+void git_inflate_end(git_zstream *strm)
+{
+       int status;
+
+       zlib_pre_call(strm);
+       status = inflateEnd(&strm->z);
+       zlib_post_call(strm);
+       if (status == Z_OK)
+               return;
+       error("inflateEnd: %s (%s)", zerr_to_string(status),
+             strm->z.msg ? strm->z.msg : "no message");
+}
+
+int git_inflate(git_zstream *strm, int flush)
+{
+       int status;
+
+       for (;;) {
+               zlib_pre_call(strm);
+               /* Never say Z_FINISH unless we are feeding everything */
+               status = inflate(&strm->z,
+                                (strm->z.avail_in != strm->avail_in)
+                                ? 0 : flush);
+               if (status == Z_MEM_ERROR)
+                       die("inflate: out of memory");
+               zlib_post_call(strm);
+
+               /*
+                * Let zlib work another round, while we can still
+                * make progress.
+                */
+               if ((strm->avail_out && !strm->z.avail_out) &&
+                   (status == Z_OK || status == Z_BUF_ERROR))
+                       continue;
                break;
+       }
+
+       switch (status) {
+       /* Z_BUF_ERROR: normal, needs more space in the output buffer */
+       case Z_BUF_ERROR:
+       case Z_OK:
+       case Z_STREAM_END:
+               return status;
        default:
-               err = "error";
+               break;
        }
-       die("inflateInit: %s (%s)", err, strm->msg ? strm->msg : "no message");
+       error("inflate: %s (%s)", zerr_to_string(status),
+             strm->z.msg ? strm->z.msg : "no message");
+       return status;
 }
 
-void git_inflate_end(z_streamp strm)
+#if defined(NO_DEFLATE_BOUND) || ZLIB_VERNUM < 0x1200
+#define deflateBound(c,s)  ((s) + (((s) + 7) >> 3) + (((s) + 63) >> 6) + 11)
+#endif
+
+unsigned long git_deflate_bound(git_zstream *strm, unsigned long size)
 {
-       if (inflateEnd(strm) != Z_OK)
-               error("inflateEnd: %s", strm->msg ? strm->msg : "failed");
+       return deflateBound(&strm->z, size);
 }
 
-int git_inflate(z_streamp strm, int flush)
+void git_deflate_init(git_zstream *strm, int level)
 {
-       int ret = inflate(strm, flush);
-       const char *err;
+       int status;
 
-       switch (ret) {
-       /* Out of memory is fatal. */
-       case Z_MEM_ERROR:
-               die("inflate: out of memory");
+       zlib_pre_call(strm);
+       status = deflateInit(&strm->z, level);
+       zlib_post_call(strm);
+       if (status == Z_OK)
+               return;
+       die("deflateInit: %s (%s)", zerr_to_string(status),
+           strm->z.msg ? strm->z.msg : "no message");
+}
 
-       /* Data corruption errors: we may want to recover from them (fsck) */
-       case Z_NEED_DICT:
-               err = "needs dictionary"; break;
-       case Z_DATA_ERROR:
-               err = "data stream error"; break;
-       case Z_STREAM_ERROR:
-               err = "stream consistency error"; break;
-       default:
-               err = "unknown error"; break;
+void git_deflate_init_gzip(git_zstream *strm, int level)
+{
+       /*
+        * Use default 15 bits, +16 is to generate gzip header/trailer
+        * instead of the zlib wrapper.
+        */
+       const int windowBits = 15 + 16;
+       int status;
+
+       zlib_pre_call(strm);
+       status = deflateInit2(&strm->z, level,
+                                 Z_DEFLATED, windowBits,
+                                 8, Z_DEFAULT_STRATEGY);
+       zlib_post_call(strm);
+       if (status == Z_OK)
+               return;
+       die("deflateInit2: %s (%s)", zerr_to_string(status),
+           strm->z.msg ? strm->z.msg : "no message");
+}
+
+int git_deflate_abort(git_zstream *strm)
+{
+       int status;
 
+       zlib_pre_call(strm);
+       status = deflateEnd(&strm->z);
+       zlib_post_call(strm);
+       return status;
+}
+
+void git_deflate_end(git_zstream *strm)
+{
+       int status = git_deflate_abort(strm);
+
+       if (status == Z_OK)
+               return;
+       error("deflateEnd: %s (%s)", zerr_to_string(status),
+             strm->z.msg ? strm->z.msg : "no message");
+}
+
+int git_deflate_end_gently(git_zstream *strm)
+{
+       int status;
+
+       zlib_pre_call(strm);
+       status = deflateEnd(&strm->z);
+       zlib_post_call(strm);
+       return status;
+}
+
+int git_deflate(git_zstream *strm, int flush)
+{
+       int status;
+
+       for (;;) {
+               zlib_pre_call(strm);
+
+               /* Never say Z_FINISH unless we are feeding everything */
+               status = deflate(&strm->z,
+                                (strm->z.avail_in != strm->avail_in)
+                                ? 0 : flush);
+               if (status == Z_MEM_ERROR)
+                       die("deflate: out of memory");
+               zlib_post_call(strm);
+
+               /*
+                * Let zlib work another round, while we can still
+                * make progress.
+                */
+               if ((strm->avail_out && !strm->z.avail_out) &&
+                   (status == Z_OK || status == Z_BUF_ERROR))
+                       continue;
+               break;
+       }
+
+       switch (status) {
        /* Z_BUF_ERROR: normal, needs more space in the output buffer */
        case Z_BUF_ERROR:
        case Z_OK:
        case Z_STREAM_END:
-               return ret;
+               return status;
+       default:
+               break;
        }
-       error("inflate: %s (%s)", err, strm->msg ? strm->msg : "no message");
-       return ret;
+       error("deflate: %s (%s)", zerr_to_string(status),
+             strm->z.msg ? strm->z.msg : "no message");
+       return status;
 }