Code clean up: use range-style for loops wherever possible

Where not possible, use "auto" to get the iterator type.

Editorial note: I have avoid this change for a long time because of
not wanting to make gratuitous changes to version history, which can
obscure when certain changes were made, but with having recently
touched every single file to apply automatic code formatting and with
making several broad changes to the API, I decided it was time to take
the plunge and get rid of the older (pre-C++11) verbose iterator
syntax. The new code is just easier to read and understand, and in
many cases, it will be more effecient as fewer temporary copies are
being made.

m-holger, if you're reading, you can see that I've finally come
around. :-)

1 files changed, 48 insertions, 108 deletions

diff --git a/libqpdf/QPDFWriter.cc b/libqpdf/QPDFWriter.cc
index 962a8a6c..215af009 100644
--- a/libqpdf/QPDFWriter.cc
+++ b/libqpdf/QPDFWriter.cc
@@ -755,10 +755,8 @@ QPDFWriter::setEncryptionParameters(
 
     int P = 0;
     // Create the complement of P, then invert.
-    for (std::set<int>::iterator iter = bits_to_clear.begin();
-         iter != bits_to_clear.end();
-         ++iter) {
-        P |= (1 << ((*iter) - 1));
+    for (int b: bits_to_clear) {
+        P |= (1 << (b - 1));
     }
     P = ~P;
 
@@ -1277,11 +1275,8 @@ QPDFWriter::assignCompressedObjectNumbers(QPDFObjGen const& og)
 
     // Reserve numbers for the objects that belong to this object
     // stream.
-    for (std::set<QPDFObjGen>::iterator iter =
-             this->m->object_stream_to_objects[objid].begin();
-         iter != this->m->object_stream_to_objects[objid].end();
-         ++iter) {
-        this->m->obj_renumber[*iter] = this->m->next_objid++;
+    for (auto const& iter: this->m->object_stream_to_objects[objid]) {
+        this->m->obj_renumber[iter] = this->m->next_objid++;
     }
 }
 
@@ -1353,11 +1348,9 @@ QPDFWriter::enqueueObject(QPDFObjectHandle object)
         }
     } else if (object.isDictionary()) {
         std::set<std::string> keys = object.getKeys();
-        for (std::set<std::string>::iterator iter = keys.begin();
-             iter != keys.end();
-             ++iter) {
+        for (auto const& key: keys) {
             if (!this->m->linearized) {
-                enqueueObject(object.getKey(*iter));
+                enqueueObject(object.getKey(key));
             }
         }
     } else {
@@ -1401,10 +1394,7 @@ QPDFWriter::writeTrailer(
         writeString(QUtil::int_to_string(size));
     } else {
         std::set<std::string> keys = trailer.getKeys();
-        for (std::set<std::string>::iterator iter = keys.begin();
-             iter != keys.end();
-             ++iter) {
-            std::string const& key = *iter;
+        for (auto const& key: keys) {
             writeStringQDF("  ");
             writeStringNoQDF(" ");
             writeString(QPDF_Name::normalizeName(key));
@@ -1758,11 +1748,7 @@ QPDFWriter::unparseObject(
         writeStringQDF("\n");
 
         std::set<std::string> keys = object.getKeys();
-        for (std::set<std::string>::iterator iter = keys.begin();
-             iter != keys.end();
-             ++iter) {
-            std::string const& key = *iter;
-
+        for (auto const& key: keys) {
             writeStringQDF(indent);
             writeStringQDF("  ");
             writeStringNoQDF(" ");
@@ -1930,12 +1916,9 @@ QPDFWriter::writeObjectStream(QPDFObjectHandle object)
             pushDiscardFilter(pp_ostream);
         } else {
             // Adjust offsets to skip over comment before first object
-
             first = offsets.at(0);
-            for (std::vector<qpdf_offset_t>::iterator iter = offsets.begin();
-                 iter != offsets.end();
-                 ++iter) {
-                *iter -= first;
+            for (auto& iter: offsets) {
+                iter -= first;
             }
 
             // Take one pass at writing pairs of numbers so we can get
@@ -1960,12 +1943,9 @@ QPDFWriter::writeObjectStream(QPDFObjectHandle object)
             writeObjectStreamOffsets(offsets, first_obj);
         }
 
-        int count = 0;
-        for (std::set<QPDFObjGen>::iterator iter =
-                 this->m->object_stream_to_objects[old_id].begin();
-             iter != this->m->object_stream_to_objects[old_id].end();
-             ++iter, ++count) {
-            QPDFObjGen obj = *iter;
+        int count = -1;
+        for (auto const& obj: this->m->object_stream_to_objects[old_id]) {
+            ++count;
             int new_obj = this->m->obj_renumber[obj];
             if (first_obj == -1) {
                 first_obj = new_obj;
@@ -2197,10 +2177,8 @@ QPDFWriter::generateID()
         if (trailer.hasKey("/Info")) {
             QPDFObjectHandle info = trailer.getKey("/Info");
             std::set<std::string> keys = info.getKeys();
-            for (std::set<std::string>::iterator iter = keys.begin();
-                 iter != keys.end();
-                 ++iter) {
-                QPDFObjectHandle obj = info.getKey(*iter);
+            for (auto const& key: keys) {
+                QPDFObjectHandle obj = info.getKey(key);
                 if (obj.isString()) {
                     seed += " ";
                     seed += obj.getStringValue();
@@ -2235,10 +2213,7 @@ QPDFWriter::initializeSpecialStreams()
     // normalizing.
     std::vector<QPDFObjectHandle> pages = this->m->pdf.getAllPages();
     int num = 0;
-    for (std::vector<QPDFObjectHandle>::iterator iter = pages.begin();
-         iter != pages.end();
-         ++iter) {
-        QPDFObjectHandle& page = *iter;
+    for (auto& page: pages) {
         this->m->page_object_to_seq[page.getObjGen()] = ++num;
         QPDFObjectHandle contents = page.getKey("/Contents");
         std::vector<QPDFObjGen> contents_objects;
@@ -2322,9 +2297,7 @@ QPDFWriter::generateObjectStreams()
     }
     unsigned int n = 0;
     int cur_ostream = 0;
-    for (std::vector<QPDFObjGen>::const_iterator iter = eligible.begin();
-         iter != eligible.end();
-         ++iter) {
+    for (auto const& iter: eligible) {
         if ((n % n_per) == 0) {
             if (n > 0) {
                 QTC::TC("qpdf", "QPDFWriter generate >1 ostream");
@@ -2339,7 +2312,7 @@ QPDFWriter::generateObjectStreams()
                 this->m->pdf.makeIndirectObject(QPDFObjectHandle::newNull())
                     .getObjectID();
         }
-        this->m->object_to_object_stream[*iter] = cur_ostream;
+        this->m->object_to_object_stream[iter] = cur_ostream;
         ++n;
     }
 }
@@ -2495,10 +2468,7 @@ QPDFWriter::doWriteSetup()
     if (this->m->linearized) {
         // Page dictionaries are not allowed to be compressed objects.
         std::vector<QPDFObjectHandle> pages = this->m->pdf.getAllPages();
-        for (std::vector<QPDFObjectHandle>::iterator iter = pages.begin();
-             iter != pages.end();
-             ++iter) {
-            QPDFObjectHandle& page = *iter;
+        for (auto& page: pages) {
             QPDFObjGen og = page.getObjGen();
             if (this->m->object_to_object_stream.count(og)) {
                 QTC::TC("qpdf", "QPDFWriter uncompressing page dictionary");
@@ -2521,12 +2491,9 @@ QPDFWriter::doWriteSetup()
     }
 
     // Generate reverse mapping from object stream to objects
-    for (std::map<QPDFObjGen, int>::iterator iter =
-             this->m->object_to_object_stream.begin();
-         iter != this->m->object_to_object_stream.end();
-         ++iter) {
-        QPDFObjGen obj = (*iter).first;
-        int stream = (*iter).second;
+    for (auto const& iter: this->m->object_to_object_stream) {
+        QPDFObjGen const& obj = iter.first;
+        int stream = iter.second;
         this->m->object_stream_to_objects[stream].insert(obj);
         this->m->max_ostream_index = std::max(
             this->m->max_ostream_index,
@@ -2591,11 +2558,9 @@ QPDFWriter::getWrittenXRefTable()
 {
     std::map<QPDFObjGen, QPDFXRefEntry> result;
 
-    for (std::map<int, QPDFXRefEntry>::iterator iter = this->m->xref.begin();
-         iter != this->m->xref.end();
-         ++iter) {
-        if (iter->first != 0 && iter->second.getType() != 0) {
-            result[QPDFObjGen(iter->first, 0)] = iter->second;
+    for (auto const& iter: this->m->xref) {
+        if (iter.first != 0 && iter.second.getType() != 0) {
+            result[QPDFObjGen(iter.first, 0)] = iter.second;
         }
     }
 
@@ -2605,10 +2570,8 @@ QPDFWriter::getWrittenXRefTable()
 void
 QPDFWriter::enqueuePart(std::vector<QPDFObjectHandle>& part)
 {
-    for (std::vector<QPDFObjectHandle>::iterator iter = part.begin();
-         iter != part.end();
-         ++iter) {
-        enqueueObject(*iter);
+    for (auto const& oh: part) {
+        enqueueObject(oh);
     }
 }
 
@@ -2617,14 +2580,11 @@ QPDFWriter::writeEncryptionDictionary()
 {
     this->m->encryption_dict_objid = openObject(this->m->encryption_dict_objid);
     writeString("<<");
-    for (std::map<std::string, std::string>::iterator iter =
-             this->m->encryption_dictionary.begin();
-         iter != this->m->encryption_dictionary.end();
-         ++iter) {
+    for (auto const& iter: this->m->encryption_dictionary) {
         writeString(" ");
-        writeString((*iter).first);
+        writeString(iter.first);
         writeString(" ");
-        writeString((*iter).second);
+        writeString(iter.second);
     }
     writeString(" >>");
     closeObject(this->m->encryption_dict_objid);
@@ -2937,10 +2897,8 @@ QPDFWriter::discardGeneration(
     // maps for QPDF that throw away generation numbers.
 
     out.clear();
-    for (std::map<QPDFObjGen, int>::const_iterator iter = in.begin();
-         iter != in.end();
-         ++iter) {
-        if (out.count((*iter).first.getObj())) {
+    for (auto const& iter: in) {
+        if (out.count(iter.first.getObj())) {
             throw std::runtime_error(
                 "QPDF cannot currently linearize files that contain"
                 " multiple objects with the same object ID and different"
@@ -2950,7 +2908,7 @@ QPDFWriter::discardGeneration(
                 " linearizing, and then linearize the result of that"
                 " conversion.");
         }
-        out[(*iter).first.getObj()] = (*iter).second;
+        out[iter.first.getObj()] = iter.second;
     }
 }
 
@@ -3020,10 +2978,8 @@ QPDFWriter::writeLinearized()
     // Assign numbers to all compressed objects in the second half.
     std::vector<QPDFObjectHandle>* vecs2[] = {&part7, &part8, &part9};
     for (int i = 0; i < 3; ++i) {
-        for (std::vector<QPDFObjectHandle>::iterator iter = (*vecs2[i]).begin();
-             iter != (*vecs2[i]).end();
-             ++iter) {
-            assignCompressedObjectNumbers((*iter).getObjGen());
+        for (auto const& oh: *vecs2[i]) {
+            assignCompressedObjectNumbers(oh.getObjGen());
         }
     }
     int second_half_end = this->m->next_objid - 1;
@@ -3049,10 +3005,8 @@ QPDFWriter::writeLinearized()
     // Assign numbers to all compressed objects in the first half
     std::vector<QPDFObjectHandle>* vecs1[] = {&part4, &part6};
     for (int i = 0; i < 2; ++i) {
-        for (std::vector<QPDFObjectHandle>::iterator iter = (*vecs1[i]).begin();
-             iter != (*vecs1[i]).end();
-             ++iter) {
-            assignCompressedObjectNumbers((*iter).getObjGen());
+        for (auto const& oh: *vecs1[i]) {
+            assignCompressedObjectNumbers(oh.getObjGen());
         }
     }
     int first_half_end = this->m->next_objid - 1;
@@ -3240,11 +3194,7 @@ QPDFWriter::writeLinearized()
 
         // Parts 4 through 9
 
-        for (std::list<QPDFObjectHandle>::iterator iter =
-                 this->m->object_queue.begin();
-             iter != this->m->object_queue.end();
-             ++iter) {
-            QPDFObjectHandle cur_object = (*iter);
+        for (auto const& cur_object: this->m->object_queue) {
             if (cur_object.getObjectID() == part6_end_marker) {
                 first_half_max_obj_offset = this->m->pipeline->getCount();
             }
@@ -3390,11 +3340,8 @@ QPDFWriter::enqueueObjectsStandard()
 {
     if (this->m->preserve_unreferenced_objects) {
         QTC::TC("qpdf", "QPDFWriter preserve unreferenced standard");
-        std::vector<QPDFObjectHandle> all = this->m->pdf.getAllObjects();
-        for (std::vector<QPDFObjectHandle>::iterator iter = all.begin();
-             iter != all.end();
-             ++iter) {
-            enqueueObject(*iter);
+        for (auto const& oh: this->m->pdf.getAllObjects()) {
+            enqueueObject(oh);
         }
     }
 
@@ -3407,10 +3354,8 @@ QPDFWriter::enqueueObjectsStandard()
     // Root is already there, so enqueuing it a second time is a
     // no-op.
     std::set<std::string> keys = trailer.getKeys();
-    for (std::set<std::string>::iterator iter = keys.begin();
-         iter != keys.end();
-         ++iter) {
-        enqueueObject(trailer.getKey(*iter));
+    for (auto const& key: keys) {
+        enqueueObject(trailer.getKey(key));
     }
 }
 
@@ -3424,23 +3369,18 @@ QPDFWriter::enqueueObjectsPCLm()
 
     // enqueue all pages first
     std::vector<QPDFObjectHandle> all = this->m->pdf.getAllPages();
-    for (std::vector<QPDFObjectHandle>::iterator iter = all.begin();
-         iter != all.end();
-         ++iter) {
+    for (auto& page: all) {
         // enqueue page
-        enqueueObject(*iter);
+        enqueueObject(page);
 
         // enqueue page contents stream
-        enqueueObject((*iter).getKey("/Contents"));
+        enqueueObject(page.getKey("/Contents"));
 
         // enqueue all the strips for each page
-        QPDFObjectHandle strips =
-            (*iter).getKey("/Resources").getKey("/XObject");
+        QPDFObjectHandle strips = page.getKey("/Resources").getKey("/XObject");
         std::set<std::string> keys = strips.getKeys();
-        for (std::set<std::string>::iterator image = keys.begin();
-             image != keys.end();
-             ++image) {
-            enqueueObject(strips.getKey(*image));
+        for (auto const& image: keys) {
+            enqueueObject(strips.getKey(image));
             enqueueObject(QPDFObjectHandle::newStream(
                 &this->m->pdf, image_transform_content));
         }