[gmime] Fixed GMimeFilterGZip's zip logic to be more robust

[Jeffrey Stedfast <fejj src gnome org>]

commit 0d5f4f9f17c3354d5d870a8283fbc76359484858
Author: Jeffrey Stedfast <jestedfa microsoft com>
Date:   Thu Dec 14 22:38:39 2017 -0500

    Fixed GMimeFilterGZip's zip logic to be more robust

 gmime/gmime-filter-gzip.c |  115 +++++++++++++++++++++++++++++----------------
 tests/test-filters.c      |    2 +-
 2 files changed, 76 insertions(+), 41 deletions(-)
---
diff --git a/gmime/gmime-filter-gzip.c b/gmime/gmime-filter-gzip.c
index bc0e98f..4c8fca3 100644
--- a/gmime/gmime-filter-gzip.c
+++ b/gmime/gmime-filter-gzip.c
@@ -219,12 +219,19 @@ filter_copy (GMimeFilter *filter)
        return g_mime_filter_gzip_new (gzip->mode, gzip->level);
 }
 
+static inline size_t
+next_alloc_size (size_t n)
+{
+       return (n + 1023) & ~1023;
+}
+
 static void
 gzip_filter (GMimeFilter *filter, char *in, size_t len, size_t prespace,
-            char **out, size_t *outlen, size_t *outprespace, int flush)
+            char **out, size_t *outlen, size_t *outprespace, gboolean flush)
 {
        GMimeFilterGZip *gzip = (GMimeFilterGZip *) filter;
        struct _GMimeFilterGZipPrivate *priv = gzip->priv;
+       size_t atleast, olen;
        int retval;
        
        if (priv->state.zip.flushed) {
@@ -257,7 +264,8 @@ gzip_filter (GMimeFilter *filter, char *in, size_t len, size_t prespace,
                        priv->hdr.v.xfl = 0;
                priv->hdr.v.os = GZIP_OS_UNKNOWN;
                
-               g_mime_filter_set_size (filter, (len * 2) + hdrlen + 12, FALSE);
+               atleast = next_alloc_size ((len * 2) + hdrlen + 12);
+               g_mime_filter_set_size (filter, atleast, FALSE);
                
                memcpy (filter->outbuf, priv->hdr.buf, 10);
                outptr = filter->outbuf + 10;
@@ -277,7 +285,8 @@ gzip_filter (GMimeFilter *filter, char *in, size_t len, size_t prespace,
                
                priv->state.zip.wrote_hdr = TRUE;
        } else {
-               g_mime_filter_set_size (filter, (len * 2) + 12, FALSE);
+               atleast = next_alloc_size ((len * 2) + 12);
+               g_mime_filter_set_size (filter, atleast, FALSE);
                
                priv->stream->next_out = (unsigned char *) filter->outbuf;
                priv->stream->avail_out = filter->outsize;
@@ -287,45 +296,71 @@ gzip_filter (GMimeFilter *filter, char *in, size_t len, size_t prespace,
        priv->stream->avail_in = len;
        
        do {
-               /* FIXME: handle error cases? */
-               if ((retval = deflate (priv->stream, flush)) != Z_OK) {
+               retval = deflate (priv->stream, Z_NO_FLUSH);
+               
+               if (retval != Z_OK && !(retval == Z_BUF_ERROR && !priv->stream->avail_in)) {
                        w(fprintf (stderr, "gzip: %d: %s\n", retval, priv->stream->msg));
                        break;
                }
                
-               if (flush == Z_FULL_FLUSH) {
-                       size_t olen;
-                       
-                       olen = filter->outsize - priv->stream->avail_out;
-                       g_mime_filter_set_size (filter, olen + (priv->stream->avail_in * 2) + 12, TRUE);
-                       priv->stream->next_out = (unsigned char *) filter->outbuf + olen;
-                       priv->stream->avail_out = filter->outsize - olen;
-                       
-                       if (priv->stream->avail_in == 0) {
-                               guint32 val;
-                               
-                               val = GUINT32_TO_LE (priv->crc32);
-                               memcpy (priv->stream->next_out, &val, 4);
-                               priv->stream->avail_out -= 4;
-                               priv->stream->next_out += 4;
-                               
-                               val = GUINT32_TO_LE (priv->isize);
-                               memcpy (priv->stream->next_out, &val, 4);
-                               priv->stream->avail_out -= 4;
-                               priv->stream->next_out += 4;
-                               
-                               priv->state.zip.flushed = TRUE;
-                               break;
-                       }
-               } else {
-                       if (priv->stream->avail_in > 0)
+               if (priv->stream->avail_out > 0) {
+                       if (priv->stream->avail_in > 0) {
                                g_mime_filter_backup (filter, (char *) priv->stream->next_in,
                                                      priv->stream->avail_in);
-                       
+                       }
                        break;
                }
+               
+               if (priv->stream->avail_in == 0)
+                       break;
+               
+               olen = filter->outsize - priv->stream->avail_out;
+               atleast = next_alloc_size (olen + priv->stream->avail_in * 2);
+               g_mime_filter_set_size (filter, atleast, TRUE);
+               priv->stream->next_out = (unsigned char *) filter->outbuf + olen;
+               priv->stream->avail_out = filter->outsize - olen;
        } while (1);
        
+       if (flush) {
+               guint32 val;
+               
+               do {
+                       retval = deflate (priv->stream, Z_FULL_FLUSH);
+                       
+                       if (retval != Z_OK && !(retval == Z_BUF_ERROR && !priv->stream->avail_in)) {
+                               w(fprintf (stderr, "gzip: %d: %s\n", retval, priv->stream->msg));
+                               break;
+                       }
+                       
+                       if (priv->stream->avail_out > 0)
+                               break;
+                       
+                       olen = filter->outsize;
+                       g_mime_filter_set_size (filter, olen + 1024, TRUE);
+                       priv->stream->next_out = (unsigned char *) filter->outbuf + olen;
+                       priv->stream->avail_out = filter->outsize - olen;
+               } while (1);
+               
+               if (priv->stream->avail_out < 8) {
+                       olen = filter->outsize;
+                       g_mime_filter_set_size (filter, olen + 8, TRUE);
+                       priv->stream->next_out = (unsigned char *) filter->outbuf + olen;
+                       priv->stream->avail_out = filter->outsize - olen;
+               }
+               
+               val = GUINT32_TO_LE (priv->crc32);
+               memcpy (priv->stream->next_out, &val, 4);
+               priv->stream->avail_out -= 4;
+               priv->stream->next_out += 4;
+               
+               val = GUINT32_TO_LE (priv->isize);
+               memcpy (priv->stream->next_out, &val, 4);
+               priv->stream->avail_out -= 4;
+               priv->stream->next_out += 4;
+               
+               priv->state.zip.flushed = TRUE;
+       }
+       
        priv->crc32 = crc32 (priv->crc32, (unsigned char *) in, len - priv->stream->avail_in);
        priv->isize += len - priv->stream->avail_in;
        
@@ -336,7 +371,7 @@ gzip_filter (GMimeFilter *filter, char *in, size_t len, size_t prespace,
 
 static void
 gunzip_filter (GMimeFilter *filter, char *in, size_t len, size_t prespace,
-              char **out, size_t *outlen, size_t *outprespace, int flush)
+              char **out, size_t *outlen, size_t *outprespace, gboolean flush)
 {
        GMimeFilterGZip *gzip = (GMimeFilterGZip *) filter;
        struct _GMimeFilterGZipPrivate *priv = gzip->priv;
@@ -450,7 +485,7 @@ gunzip_filter (GMimeFilter *filter, char *in, size_t len, size_t prespace,
                left -= 2;
        }
        
-       if (left == 0 && flush != Z_FULL_FLUSH)
+       if (left == 0 && !flush)
                return;
        
        g_mime_filter_set_size (filter, (left * 2) + 12, FALSE);
@@ -464,7 +499,7 @@ gunzip_filter (GMimeFilter *filter, char *in, size_t len, size_t prespace,
        do {
                /* FIXME: handle error cases? */
                /* Note: Z_BUF_ERROR is not really an error unless there is input available */
-               retval = inflate (priv->stream, flush);
+               retval = inflate (priv->stream, flush ? Z_FULL_FLUSH : Z_NO_FLUSH);
                
                if (retval != Z_OK && !(retval == Z_BUF_ERROR && !priv->stream->avail_in)) {
                        w(fprintf (stderr, "gunzip: %d: %s\n", retval, priv->stream->msg));
@@ -474,7 +509,7 @@ gunzip_filter (GMimeFilter *filter, char *in, size_t len, size_t prespace,
                if (priv->stream->avail_in == 0)
                        break;
                
-               if (flush == Z_FULL_FLUSH) {
+               if (flush) {
                        size_t olen = filter->outsize - priv->stream->avail_out;
                        
                        g_mime_filter_set_size (filter, olen + (priv->stream->avail_in * 2) + 12, TRUE);
@@ -505,9 +540,9 @@ filter_filter (GMimeFilter *filter, char *in, size_t len, size_t prespace,
        GMimeFilterGZip *gzip = (GMimeFilterGZip *) filter;
        
        if (gzip->mode == GMIME_FILTER_GZIP_MODE_ZIP)
-               gzip_filter (filter, in, len, prespace, out, outlen, outprespace, Z_NO_FLUSH);
+               gzip_filter (filter, in, len, prespace, out, outlen, outprespace, FALSE);
        else
-               gunzip_filter (filter, in, len, prespace, out, outlen, outprespace, Z_NO_FLUSH);
+               gunzip_filter (filter, in, len, prespace, out, outlen, outprespace, FALSE);
 }
 
 static void
@@ -517,9 +552,9 @@ filter_complete (GMimeFilter *filter, char *in, size_t len, size_t prespace,
        GMimeFilterGZip *gzip = (GMimeFilterGZip *) filter;
        
        if (gzip->mode == GMIME_FILTER_GZIP_MODE_ZIP)
-               gzip_filter (filter, in, len, prespace, out, outlen, outprespace, Z_FULL_FLUSH);
+               gzip_filter (filter, in, len, prespace, out, outlen, outprespace, TRUE);
        else
-               gunzip_filter (filter, in, len, prespace, out, outlen, outprespace, Z_FULL_FLUSH);
+               gunzip_filter (filter, in, len, prespace, out, outlen, outprespace, TRUE);
 }
 
 /* should this 'flush' outstanding state/data bytes? */
diff --git a/tests/test-filters.c b/tests/test-filters.c
index afd2ce5..67877cf 100644
--- a/tests/test-filters.c
+++ b/tests/test-filters.c
@@ -122,7 +122,7 @@ test_gzip (const char *datadir, const char *filename)
        g_mime_filter_gzip_set_filename ((GMimeFilterGZip *) filter, filename);
        g_mime_filter_gzip_set_comment ((GMimeFilterGZip *) filter, "This is a comment.");
        
-       pump_data_through_filter (filter, path, stream, TRUE, FALSE);
+       pump_data_through_filter (filter, path, stream, TRUE, TRUE);
        g_mime_filter_reset (filter);
        g_object_unref (stream);
        g_object_unref (filter);