split out page handling into new module

1 files changed, 138 insertions, 0 deletions

diff --git a/src/page.c b/src/page.c
new file mode 100644
index 0000000..bca6dbc
--- /dev/null
+++ b/src/page.c
@@ -0,0 +1,138 @@
+/*
+ * Copyright 2018 Vincent Sanders <vince@netsurf-browser.org>
+ *
+ * This file is part of libnspdf.
+ *
+ * Licensed under the MIT License,
+ *                http://www.opensource.org/licenses/mit-license.php
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <nspdf/page.h>
+
+#include "cos_object.h"
+#include "pdf_doc.h"
+
+/**
+ * recursively decodes a page tree
+ */
+nspdferror
+nspdf__decode_page_tree(struct nspdf_doc *doc,
+                 struct cos_object *page_tree_node,
+                 unsigned int *page_index)
+{
+    nspdferror res;
+    const char *type;
+
+    // Type = Pages
+    res = cos_get_dictionary_name(doc, page_tree_node, "Type", &type);
+    if (res != NSPDFERROR_OK) {
+        return res;
+    }
+
+    if (strcmp(type, "Pages") == 0) {
+        struct cos_object *kids;
+        unsigned int kids_size;
+        unsigned int kids_index;
+
+        if (doc->page_table == NULL) {
+            /* allocate top level page table */
+            int64_t count;
+
+            res = cos_get_dictionary_int(doc, page_tree_node, "Count", &count);
+            if (res != NSPDFERROR_OK) {
+                return res;
+            }
+
+            doc->page_table = calloc(count, sizeof(struct page_table_entry));
+            if (doc->page_table == NULL) {
+                return NSPDFERROR_NOMEM;
+            }
+            doc->page_table_size = count;
+        }
+
+        res = cos_get_dictionary_array(doc, page_tree_node, "Kids", &kids);
+        if (res != NSPDFERROR_OK) {
+            return res;
+        }
+
+        res = cos_get_array_size(doc, kids, &kids_size);
+        if (res != NSPDFERROR_OK) {
+            return res;
+        }
+
+        for (kids_index = 0; kids_index < kids_size; kids_index++) {
+            struct cos_object *kid;
+
+            res = cos_get_array_dictionary(doc, kids, kids_index, &kid);
+            if (res != NSPDFERROR_OK) {
+                return res;
+            }
+
+            res = nspdf__decode_page_tree(doc, kid, page_index);
+            if (res != NSPDFERROR_OK) {
+                return res;
+            }
+        }
+
+    } else if (strcmp(type, "Page") == 0) {
+        struct page_table_entry *page;
+
+        page = doc->page_table + (*page_index);
+
+        /* required heritable resources */
+        res = cos_heritable_dictionary_dictionary(doc,
+                                                  page_tree_node,
+                                                  "Resources",
+                                                  &(page->resources));
+        if (res != NSPDFERROR_OK) {
+            return res;
+        }
+
+        /* required heritable mediabox */
+        res = cos_heritable_dictionary_array(doc,
+                                             page_tree_node,
+                                             "MediaBox",
+                                             &(page->mediabox));
+        if (res != NSPDFERROR_OK) {
+            return res;
+        }
+
+        /* optional page contents */
+        res = cos_get_dictionary_value(doc,
+                                       page_tree_node,
+                                       "Contents",
+                                       &(page->contents));
+        if ((res != NSPDFERROR_OK) &&
+            (res != NSPDFERROR_NOTFOUND)) {
+            return res;
+        }
+
+        /*
+        printf("page index:%d page:%p resources:%p mediabox:%p contents:%p\n",
+               *page_index,
+               page,
+               page->resources,
+               page->mediabox,
+               page->contents);
+        */
+
+        (*page_index)++;
+        res = NSPDFERROR_OK;
+    } else {
+        res = NSPDFERROR_FORMAT;
+    }
+    return res;
+}
+
+/* exported interface documented in nspdf/page.h */
+nspdferror
+nspdf_count_pages(struct nspdf_doc *doc, unsigned int *pages_out)
+{
+    *pages_out = doc->page_table_size;
+    return NSPDFERROR_OK;
+}