Implement --set-page-labels and supporting API (fixes #939)

3 files changed, 34 insertions, 2 deletions

diff --git a/include/qpdf/Constants.h b/include/qpdf/Constants.h
index 24f7dc3a..89152a91 100644
--- a/include/qpdf/Constants.h
+++ b/include/qpdf/Constants.h
@@ -232,4 +232,14 @@ enum pdf_annotation_flag_e {
 /* Encryption/password status for QPDFJob */
 enum qpdf_encryption_status_e { qpdf_es_encrypted = 1 << 0, qpdf_es_password_incorrect = 1 << 1 };
 
+/* Page label types */
+enum qpdf_page_label_e {
+    pl_none,
+    pl_digits,
+    pl_alpha_lower,
+    pl_alpha_upper,
+    pl_roman_lower,
+    pl_roman_upper,
+};
+
 #endif /* QPDFCONSTANTS_H */
diff --git a/include/qpdf/QPDFJob.hh b/include/qpdf/QPDFJob.hh
index 9a7afb0f..4626c264 100644
--- a/include/qpdf/QPDFJob.hh
+++ b/include/qpdf/QPDFJob.hh
@@ -296,7 +296,8 @@ class QPDFJob
         Config* config;
     };
 
-    class PageLabelsConfig {
+    class PageLabelsConfig
+    {
         friend class QPDFJob;
         friend class Config;
 
@@ -458,6 +459,22 @@ class QPDFJob
         std::vector<int> repeat_pagenos;
     };
 
+    struct PageLabelSpec
+    {
+        PageLabelSpec(
+            int first_page, qpdf_page_label_e label_type, int start_num, std::string_view prefix) :
+            first_page(first_page),
+            label_type(label_type),
+            start_num(start_num),
+            prefix(prefix)
+        {
+        }
+        int first_page;
+        qpdf_page_label_e label_type;
+        int start_num{1};
+        std::string prefix;
+    };
+
     // Helper functions
     static void usage(std::string const& msg);
     static JSON json_schema(int json_version, std::set<std::string>* keys = nullptr);
@@ -694,7 +711,7 @@ class QPDFJob
         bool json_output{false};
         std::string update_from_json;
         bool report_mem_usage{false};
-        std::vector<std::string> page_label_specs;
+        std::vector<PageLabelSpec> page_label_specs;
     };
     std::shared_ptr<Members> m;
 };
diff --git a/include/qpdf/QPDFPageLabelDocumentHelper.hh b/include/qpdf/QPDFPageLabelDocumentHelper.hh
index eb610544..57b6919c 100644
--- a/include/qpdf/QPDFPageLabelDocumentHelper.hh
+++ b/include/qpdf/QPDFPageLabelDocumentHelper.hh
@@ -49,6 +49,11 @@ class QPDFPageLabelDocumentHelper: public QPDFDocumentHelper
     QPDF_DLL
     bool hasPageLabels();
 
+    // Helper function to create a dictionary suitable for adding to the /PageLabels numbers tree.
+    QPDF_DLL
+    static QPDFObjectHandle
+    pageLabelDict(qpdf_page_label_e label_type, int start_num, std::string_view prefix);
+
     // Return a page label dictionary representing the page label for the given page. The page does
     // not need to appear explicitly in the page label dictionary. This method will adjust /St as
     // needed to produce a label that is suitable for the page.