GhostPDF - warn on use of /DeviceN /All

The /All in name is illegal in PDF (it is valid in PostScript). Acrobat
allegedly seems to accept this; if the ink name array only has one
entry and the entry is /All it seems to convert it to a /Sepaaration
/All, which is equivalent.

However sometimes (tests_private/comparefiles/Testform.v1.0.2.pdf) it
throws an error instead. Possibly this is a change in behaviour with
more recent versions of Acrobat.

In any event, we now raise a warning.

3 files changed, 20 insertions, 3 deletions

diff --git a/pdf/ghostpdf.c b/pdf/ghostpdf.c
index bfa8b7756..e0eaa1d9a 100644
--- a/pdf/ghostpdf.c
+++ b/pdf/ghostpdf.c
@@ -374,8 +374,9 @@ const char *pdf_warning_strings[] = {
     "bad trailer dictionary",
     "error in annotation",
     "failed to create ICC profile link",
-    "overflowed a real reading a number, assuming 0"
-    "failed to read a valid number, assuming 0"
+    "overflowed a real reading a number, assuming 0",
+    "failed to read a valid number, assuming 0",
+    "A DeviceN space used the /All ink name."
     ""                                                  /* Last warning shuld not be used */
 };
 
diff --git a/pdf/ghostpdf.h b/pdf/ghostpdf.h
index b83e3ea02..9d10d0f74 100644
--- a/pdf/ghostpdf.h
+++ b/pdf/ghostpdf.h
@@ -115,6 +115,7 @@ typedef enum pdf_warning_e {
     W_PDF_BAD_ICC_PROFILE_LINK,
     W_PDF_OVERFLOW_REAL,
     W_PDF_INVALID_REAL,
+    W_PDF_DEVICEN_USES_ALL,
     W_PDF_MAX_WARNING               /* Must be last entry, add new warnings immediately before this and update pdf_warning_strings in ghostpdf.c */
 } pdf_warning;
 
diff --git a/pdf/pdf_colour.c b/pdf/pdf_colour.c
index aa5048eb7..e6061db1f 100644
--- a/pdf/pdf_colour.c
+++ b/pdf/pdf_colour.c
@@ -1665,8 +1665,23 @@ static int pdfi_create_DeviceN(pdf_context *ctx, pdf_array *color_array, int ind
     if (code < 0)
         goto pdfi_devicen_error;
 
+    for (ix = 0;ix < pdfi_array_size(inks);ix++) {
+        pdf_name *ink_name = NULL;
+
+        code = pdfi_array_get_type(ctx, inks, ix, PDF_NAME, (pdf_obj **)&ink_name);
+        if (code < 0)
+            return code;
+
+        if (ink_name->length == 3 && memcmp(ink_name->data, "All", 3) == 0) {
+            pdfi_set_warning(ctx, 0, NULL, W_PDF_DEVICEN_USES_ALL, "pdfi_create_DeviceN", (char *)"WARNING: DeviceN space using /All ink name");
+        }
+        pdfi_countdown(ink_name);
+        ink_name = NULL;
+    }
+
     /* Sigh, Acrobat allows this, even though its contra the spec. Convert to
-     * a /Separation space, and then return.
+     * a /Separation space, and then return. Actually Acrobat does not always permit this, see
+     * tests_private/comparefiles/Testform.v1.0.2.pdf.
      */
     if (pdfi_array_size(inks) == 1) {
         pdf_name *ink_name = NULL;