From 613cf1198f7f4cbdbce33c9439bc55ae14f3ce09 Mon Sep 17 00:00:00 2001
From: Kevin Day <Kevin@kevux.org>
Date: Mon, 2 Nov 2026 21:14:44 -0600
Subject: [PATCH] Progress: Continue work on the write functions.

This is in the middle of changing the logic in `private_fl_fss_basic_write()`.

I noticed that I was forgetting to handle the `F_bound` case for a joiner where the character to the right no longer can be processed.
I need to verify that I did this for the read functions.
I need to add unit tests for catching these cases as well, if I have not done so already.
---
 level_1/fl_fss/c/fss/basic.h         |   2 +
 level_1/fl_fss/c/fss/basic_list.c    |  10 +-
 level_1/fl_fss/c/fss/embedded_list.c |   2 +
 level_1/fl_fss/c/fss/extended.h      |   8 +
 level_1/fl_fss/c/fss/extended_list.c |   2 +
 level_1/fl_fss/c/private-fss-list.c  |   7 +-
 level_1/fl_fss/c/private-fss.c       | 236 ++++++++++++++++++---------
 level_1/fl_fss/c/private-fss.h       |   2 +
 8 files changed, 192 insertions(+), 77 deletions(-)

diff --git a/level_1/fl_fss/c/fss/basic.h b/level_1/fl_fss/c/fss/basic.h
index 304e6b785..20c0919db 100644
--- a/level_1/fl_fss/c/fss/basic.h
+++ b/level_1/fl_fss/c/fss/basic.h
@@ -218,6 +218,7 @@ extern "C" {
  *     Errors (with error bit) from: f_fss_skip_past_space().
  *     Errors (with error bit) from: f_fss_slash_count().
  *     Errors (with error bit) from: f_memory_array_increase_by().
+ *     Errors (with error bit) from: f_utf_buffer_decrement().
  *     Errors (with error bit) from: f_utf_buffer_increment().
  *
  * @see f_fss_count_slash()
@@ -228,6 +229,7 @@ extern "C" {
  * @see f_fss_skip_past_delimit()
  * @see f_fss_skip_past_space()
  * @see f_memory_array_increase_by()
+ * @see f_utf_buffer_decrement()
  * @see f_utf_buffer_increment()
  */
 #ifndef _di_fl_fss_basic_object_read_
diff --git a/level_1/fl_fss/c/fss/basic_list.c b/level_1/fl_fss/c/fss/basic_list.c
index 0fcbbcf78..dd3c066d8 100644
--- a/level_1/fl_fss/c/fss/basic_list.c
+++ b/level_1/fl_fss/c/fss/basic_list.c
@@ -111,7 +111,13 @@ extern "C" {
         flag_fl &= ~___fl_flag_do_escape___;
 
         if (range->start > range->stop || range->start >= buffer.used) break;
-        if (state->status == F_combarudoo || state->status == F_bound) continue;
+
+        if (state->status == F_combarudoo || state->status == F_bound)  {
+            f_fss_skip_past_combining_joiner(buffer, range, state);
+            if (F_status_is_error(state->status)) return;
+
+            continue;
+          }
 
         if (buffer.string[range->start] == f_fss_basic_list_open_s.string[0]) {
           flag_fl &= ~___fl_flag_has_graph_first___;
@@ -877,6 +883,8 @@ extern "C" {
         f_fss_count_slash(object, range, &slash_count, state);
         if (F_status_is_error(state->status)) break;
 
+        // TODO: Handle this returning F_combarudoo and F_bound.
+
         // Only slashes at the end of the object must be delimited to avoid delimiting the object close character.
         if (range->start > range->stop || range->start >= object.used) {
           slash_count *= 2;
diff --git a/level_1/fl_fss/c/fss/embedded_list.c b/level_1/fl_fss/c/fss/embedded_list.c
index 4940d40a2..eef32a450 100644
--- a/level_1/fl_fss/c/fss/embedded_list.c
+++ b/level_1/fl_fss/c/fss/embedded_list.c
@@ -1140,6 +1140,8 @@ extern "C" {
         f_fss_count_slash(object, range, &slash_count, state);
         if (F_status_is_error(state->status)) return;
 
+        // TODO: Handle this returning F_combarudoo and F_bound.
+
         // Only slashes at the end of the object must be delimited to avoid delimiting the object close character.
         if (range->start > range->stop || range->start >= object.used) {
           slash_count *= 2;
diff --git a/level_1/fl_fss/c/fss/extended.h b/level_1/fl_fss/c/fss/extended.h
index b53cc2c42..f99d7c1dc 100644
--- a/level_1/fl_fss/c/fss/extended.h
+++ b/level_1/fl_fss/c/fss/extended.h
@@ -93,7 +93,10 @@ extern "C" {
  *     Errors (with error bit) from: f_fss_is_zero_width().
  *     Errors (with error bit) from: f_fss_skip_past_delimit().
  *     Errors (with error bit) from: f_fss_skip_past_space().
+ *     Errors (with error bit) from: f_utf_buffer_decrement().
  *     Errors (with error bit) from: f_utf_buffer_increment().
+ *     Errors (with error bit) from: fl_fss_basic_object_read().
+ *     Errors (with error bit) from: fl_fss_extended_object_read().
  *
  * @see f_fss_count_slash()
  * @see f_fss_is_graph()
@@ -101,6 +104,7 @@ extern "C" {
  * @see f_fss_is_zero_width()
  * @see f_fss_skip_past_delimit()
  * @see f_fss_skip_past_space()
+ * @see f_utf_buffer_decrement()
  * @see f_utf_buffer_increment()
  * @see fl_fss_basic_object_read()
  * @see fl_fss_extended_object_read()
@@ -244,7 +248,10 @@ extern "C" {
  *     Errors (with error bit) from: f_fss_skip_past_delimit().
  *     Errors (with error bit) from: f_fss_skip_past_space().
  *     Errors (with error bit) from: f_memory_array_increase().
+ *     Errors (with error bit) from: f_utf_buffer_decrement().
  *     Errors (with error bit) from: f_utf_buffer_increment().
+ *     Errors (with error bit) from: fl_fss_basic_object_read().
+ *     Errors (with error bit) from: fl_fss_extended_content_read().
  *
  * @see f_fss_count_slash()
  * @see f_fss_is_graph()
@@ -253,6 +260,7 @@ extern "C" {
  * @see f_fss_skip_past_delimit()
  * @see f_fss_skip_past_space()
  * @see f_memory_array_increase()
+ * @see f_utf_buffer_decrement()
  * @see f_utf_buffer_increment()
  * @see fl_fss_basic_object_read()
  * @see fl_fss_extended_content_read()
diff --git a/level_1/fl_fss/c/fss/extended_list.c b/level_1/fl_fss/c/fss/extended_list.c
index 655eb0590..3fcf98e80 100644
--- a/level_1/fl_fss/c/fss/extended_list.c
+++ b/level_1/fl_fss/c/fss/extended_list.c
@@ -875,6 +875,8 @@ extern "C" {
         f_fss_count_slash(object, range, &slash_count, state);
         if (F_status_is_error(state->status)) return;
 
+        // TODO: Handle this returning F_combarudoo and F_bound.
+
         // Only slashes at the end of the object must be delimited to avoid delimiting the object close character.
         if (range->start > range->stop || range->start >= object.used) {
           slash_count *= 2;
diff --git a/level_1/fl_fss/c/private-fss-list.c b/level_1/fl_fss/c/private-fss-list.c
index 0946e3792..9097fe701 100644
--- a/level_1/fl_fss/c/private-fss-list.c
+++ b/level_1/fl_fss/c/private-fss-list.c
@@ -120,7 +120,12 @@ extern "C" {
           return;
         }
 
-        if (state->status == F_combarudoo || state->status == F_bound) continue;
+        if (state->status == F_combarudoo || state->status == F_bound)  {
+          f_fss_skip_past_combining_joiner(buffer, range, state);
+          if (F_status_is_error(state->status)) return;
+
+          continue;
+        }
 
         if (buffer.string[range->start] == list_open.string[0]) {
           flag_fl &= ~___fl_flag_has_graph_first___;
diff --git a/level_1/fl_fss/c/private-fss.c b/level_1/fl_fss/c/private-fss.c
index d6ec550d9..a7ec188ba 100644
--- a/level_1/fl_fss/c/private-fss.c
+++ b/level_1/fl_fss/c/private-fss.c
@@ -244,8 +244,14 @@ extern "C" {
 
           f_fss_count_slash(buffer, range, &slash_count, state);
 
+          if (state->status == F_combarudoo || state->status == F_bound) {
+            f_fss_skip_past_combining_joiner(buffer, range, state);
+            if (F_status_is_error(state->status)) return;
+
+            continue;
+          }
+
           if (F_status_is_error(state->status)) return;
-          if (state->status == F_combarudoo || state->status == F_bound) continue;
 
           if (range->start >= buffer.used) {
             found->stop = buffer.used - 1;
@@ -287,7 +293,7 @@ extern "C" {
 
                   // This check sets the state status, which is then used by the condition below.
                   if (f_fss_is_space(buffer, *range, state) == F_true) {
-                    if (state->status == F_control && buffer.string[range->start] == f_fss_eol_s.string[0]) {
+                    if (buffer.string[range->start] == f_fss_eol_s.string[0]) {
 
                       // The EOL is immediately valid and is not to be checked for combining/joiners.
                       state->status = F_true;
@@ -807,12 +813,18 @@ extern "C" {
 
     #define ___fl_flag_as_object___ 0x1
 
-    #define ___fl_flag_do_handle___ 0x1
+    #define ___fl_flag_do_handle___            0x1
+    #define ___fl_flag_has_combining___        0x2
+    #define ___fl_flag_has_combining_joiner___ 0xa
+    #define ___fl_flag_has_increased___        0x4
+    #define ___fl_flag_has_joiner___           0x8
+    #define ___fl_flag_is_quoted___            0x10
+    #define ___fl_flag_is_commented___         0x20
+    #define ___fl_flag_save_partial___         0x40
 
     const f_number_unsigned_t input_start = range->start;
     const f_number_unsigned_t used_start = destination->used;
 
-    uint8_t quoted_is = F_false;
     uint8_t commented = F_false;
     uint8_t width = 0;
     uint8_t flag_fl = 0x0;
@@ -836,36 +848,54 @@ extern "C" {
 
       if (F_status_is_error_not(state->status)) {
         if (f_fss_is_combining_joiner(object, *range, state) == F_true) {
+          flag_fl |= state->status == F_combarudoo
+            ? ___fl_flag_has_combining___
+            : ___fl_flag_has_joiner___;
+
           f_fss_skip_past_combining_joiner(object, range, state);
 
           if (F_status_is_error_not(state->status)) {
-            partial.start = input_start;
-            partial.stop = range->start;
+            if (range->start > range->stop || range->start >= object.used) {
+              partial.stop = range->start;
+            }
+            else {
 
-            state->status = f_memory_array_increase_by(width, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
-          }
+              // The joined character must be considered a new, different, character.
+              if (!(flag_fl & ___fl_flag_has_joiner___)) {
+                f_utf_buffer_decrement(object, range, 1);
+              }
 
-          if (F_status_is_error_not(state->status)) {
-            state->status = f_string_dynamic_partial_append_nulless(object, partial, destination);
-          }
+              flag_fl &= ~___fl_flag_has_combining_joiner___;
 
-          if (F_status_is_error_not(state->status)) {
-            state->status = f_utf_buffer_increment(object, range, 1);
+              if (F_status_is_error_not(state->status)) {
+                partial.stop = range->start;
+
+                state->status = f_memory_array_increase_by((partial.stop - partial.start) + 4, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
+              }
+
+              if (F_status_is_error_not(state->status)) {
+                state->status = f_string_dynamic_partial_append_nulless(object, partial, destination);
+              }
+            }
           }
         }
         else if (F_status_is_error_not(state->status)) {
           range->start = input_start;
 
           if (object.string[input_start] == quote_char) {
-            quoted_is = F_true;
+            flag_fl |= ___fl_flag_is_quoted___;
           }
           else {
-            commented = F_true;
+            flag_fl |= ___fl_flag_is_commented___;
           }
         }
       }
 
-      if (F_status_is_error(state->status)) return;
+      if (F_status_is_error(state->status)) {
+        destination->used = used_start;
+
+        return;
+      }
     }
 
     for (; range->start <= range->stop && range->start < object.used; ) {
@@ -878,67 +908,89 @@ extern "C" {
       flag_fl |= ___fl_flag_do_handle___;
 
       if (object.string[range->start] == f_fss_slash_s.string[0]) {
-        // TODO: Verify no combining joiners following.
         item_first = partial.start = range->start++;
         item_total = 1;
 
         f_fss_count_slash(object, range, &item_total, state);
-        if (F_status_is_error(state->status)) return;
+        if (F_status_is_error(state->status)) break;
 
+        // End of string or end of buffer can only happen when only slashes and delimit place holders are found.
         if (range->start > range->stop || range->start >= object.used) {
+          partial.stop = range->start;
+          flag_fl |= ___fl_flag_save_partial___;
 
-          // Slashes before the final quote must be escaped when quoted, add the delimit slashes.
-          if (quoted_is) {
+          // Slashes at end of line must be escaped when there is a quote.
+          if (flag_fl & ___fl_flag_is_quoted___) {
+            item_total *= 2;
+          }
 
-            // If this is the first quote, then only a single delimit slash is needed.
-            if (item_first == input_start) {
-              state->status = f_memory_array_increase(state->step_large, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
-              if (F_status_is_error(state->status)) break;
+          break;
+        }
 
-              destination->string[destination->used++] = f_fss_slash_s.string[0];
+        if (object.string[range->start] == f_fss_eol_s.string[0]) {
+          state->status = F_status_set_error(F_okay_eol);
+
+          break;
+        }
+
+        // Found a combining/joiner, so the slashes do not escape anything.
+        if (state->status == F_combarudoo || state->status == F_bound) {
+          flag_fl |= state->status == F_combarudoo
+            ? ___fl_flag_has_combining___
+            : ___fl_flag_has_joiner___;
+        }
+        else {
+          if (object.string[range->start] == quote_char || (flag & ___fl_flag_as_object___) && object.string[range->start] == f_fss_comment_s.string[0] || f_fss_is_space(object, *range, state) == F_true) {
+            partial.stop = range->start++;
+
+            f_fss_skip_past_delimit(object, range, state);
+
+            if (F_status_is_error_not(state->status) && f_fss_is_combining_joiner(object, *range, state) == F_true) {
+              flag_fl |= state->status == F_combarudoo
+                ? ___fl_flag_has_combining___
+                : ___fl_flag_has_joiner___;
             }
             else {
-              state->status = f_memory_array_increase_by(item_total, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
-              if (F_status_is_error(state->status)) break;
-
-              for (i = 0; i < item_total; ++i) {
-                destination->string[destination->used++] = f_fss_slash_s.string[0];
-              } // for
+              range->start = partial.stop;
             }
           }
+        }
 
-          state->status = f_memory_array_increase_by(item_total, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
-          if (F_status_is_error(state->status)) break;
+        if (flag_fl & ___fl_flag_has_combining_joiner___) {
+          item_total = 0;
 
-          for (i = 0; i < item_total; ++i) {
-            destination->string[destination->used++] = f_fss_slash_s.string[0];
-          } // for
+          f_fss_skip_past_combining_joiner(object, range, state);
 
-          break;
+          // The joined character must be considered a new, different, character.
+          if (F_status_is_error_not(state->status) && !(flag_fl & ___fl_flag_has_joiner___)) {
+            f_utf_buffer_decrement(object, range, 1);
+          }
         }
 
-        if (object.string[range->start] == f_fss_eol_s.string[0]) {
-          state->status = F_status_set_error(F_okay_eol);
+        if (F_status_is_error(state->status) || range->start > range->stop || range->start >= object.used) break;
 
-          break;
-        }
+        range->start = partial.stop;
 
-        if (object.string[range->start] == quote_char) {
-          // TODO: Verify no combining joiners following.
-          item_first = range->start++;
+        if (flag_fl & ___fl_flag_has_combining_joiner___) {
+          flag_fl |= ___fl_flag_save_partial___;
+          flag_fl &= ~___fl_flag_has_combining_joiner___;
+        }
+        else if (object.string[range->start] == quote_char) {
+          ++range->start;
 
           f_fss_skip_past_delimit(object, range, state);
           if (F_status_is_error(state->status)) break;
 
           if (range->start > range->stop || range->start >= object.used) {
-            state->status = f_memory_array_increase_by(item_total + 1, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
+            state->status = f_memory_array_increase_by(item_total + 3, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
             if (F_status_is_error(state->status)) break;
 
-            for (i = 0; i < item_total; ++i) {
+            for (i = 0; i < item_total; ++i) { // TODO: what is the correct number of slashes?
               destination->string[destination->used++] = f_fss_slash_s.string[0];
             } // for
 
             destination->string[destination->used++] = quote_char;
+            item_total = 0;
 
             break;
           }
@@ -948,15 +1000,16 @@ extern "C" {
             if (F_status_is_error(state->status)) break;
           }
           else {
+            // TODO: Verify no combining joiners following.
             if (object.string[range->start] == f_fss_eol_s.string[0]) {
               state->status = F_status_set_error(F_okay_eol);
 
               break;
             }
 
-            quoted_is = F_true;
+            flag_fl |= ___fl_flag_is_quoted___;
 
-            state->status = f_memory_array_increase_by(item_total + 1, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
+            state->status = f_memory_array_increase_by(item_total + 3, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
             if (F_status_is_error(state->status)) break;
 
             // Add the slashes that delimit the slashes.
@@ -972,7 +1025,7 @@ extern "C" {
 
           width = macro_f_utf_byte_width(object.string[range->start]);
 
-          state->status = f_memory_array_increase_by(item_total + width + 1, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
+          state->status = f_memory_array_increase_by(item_total + width + 3, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
           if (F_status_is_error(state->status)) break;
 
           for (i = 0; i < item_total; ++i) {
@@ -984,6 +1037,7 @@ extern "C" {
           memcpy(destination->string + destination->used, object.string + range->start, width);
 
           destination->used += width;
+          item_total = 0;
         }
         else if ((flag & ___fl_flag_as_object___) && object.string[range->start] == f_fss_comment_s.string[0]) {
           // TODO: Verify no combining joiners following.
@@ -993,7 +1047,7 @@ extern "C" {
             commented = F_true;
           }
 
-          state->status = f_memory_array_increase_by(item_total + 1, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
+          state->status = f_memory_array_increase_by(item_total + 3, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
           if (F_status_is_error(state->status)) break;
 
           for (i = 0; i < item_total; ++i) {
@@ -1001,28 +1055,30 @@ extern "C" {
           } // for
 
           destination->string[destination->used++] = object.string[range->start++];
+          item_total = 0;
 
           continue;
         }
         else {
 
-          // If any space is found, then this must be quote.
+          // If any space is found, then this must be quoted.
           if (f_fss_is_space(object, *range, state) == F_false) {
             if (F_status_is_error(state->status)) break;
           }
           else {
+            // TODO: combining joiner check against space.
             if (object.string[range->start] == f_fss_eol_s.string[0]) {
               state->status = F_status_set_error(F_okay_eol);
 
               break;
             }
 
-            quoted_is = F_true;
+            flag_fl |= ___fl_flag_is_quoted___;
           }
 
           width = macro_f_utf_byte_width(object.string[range->start]);
 
-          state->status = f_memory_array_increase_by(item_total + width, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
+          state->status = f_memory_array_increase_by(item_total + width + 3, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
           if (F_status_is_error(state->status)) break;
 
           // There is nothing to delimit, so all slashes should be printed as is.
@@ -1033,16 +1089,17 @@ extern "C" {
           memcpy(destination->string + destination->used, object.string + range->start, width);
 
           destination->used += width;
+          item_total = 0;
         }
 
         flag_fl &= ~___fl_flag_do_handle___;
       }
       else if (object.string[range->start] == quote_char) {
         // TODO: Verify no combining joiners following.
-        item_first = range->start++;
+        item_first = partial.start = range->start++;
 
         f_fss_skip_past_delimit(object, range, state);
-        if (F_status_is_error(state->status)) return;
+        if (F_status_is_error(state->status)) break;
 
         if (range->start > range->stop || range->start >= object.used) {
           state->status = f_memory_array_increase(state->step_large, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
@@ -1080,12 +1137,12 @@ extern "C" {
 
           destination->string[destination->used++] = f_fss_slash_s.string[0];
 
-          quoted_is = F_true;
+          flag_fl |= ___fl_flag_is_quoted___;
         }
 
         width = macro_f_utf_byte_width(object.string[range->start]);
 
-        state->status = f_memory_array_increase_by(width + 1, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
+        state->status = f_memory_array_increase_by(width + 3, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
         if (F_status_is_error(state->status)) break;
 
         destination->string[destination->used++] = quote_char;
@@ -1102,20 +1159,33 @@ extern "C" {
         break;
       }
 
-      if (flag_fl & ___fl_flag_do_handle___ && object.string[range->start] != f_fss_placeholder_s.string[0]) {
-        if (!quoted_is) {
+      if (flag_fl & ___fl_flag_save_partial___) {
+        flag_fl &= ~___fl_flag_save_partial___;
+
+        if (partial.start <= partial.stop) {
+          state->status = f_memory_array_increase_by((partial.stop - partial.start) + 4, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
+
+          if (F_status_is_error_not(state->status)) {
+            state->status = f_string_dynamic_partial_append_nulless(object, partial, destination);
+          }
+
+          if (F_status_is_error(state->status)) break;
+        }
+      }
+      else if ((flag_fl & ___fl_flag_do_handle___) && object.string[range->start] != f_fss_placeholder_s.string[0]) {
+        if (!(flag_fl & ___fl_flag_is_quoted___)) {
           if (object.string[range->start] == f_string_ascii_quote_double_s.string[0] || object.string[range->start] == f_string_ascii_quote_single_s.string[0] || object.string[range->start] == f_string_ascii_grave_s.string[0]) {
             // TODO: Verify no combining joiners following.
             item_first = range->start++;
 
             f_fss_skip_past_delimit(object, range, state);
-            if (F_status_is_error(state->status)) return;
+            if (F_status_is_error(state->status)) break;
 
             if (range->start > range->stop || range->start >= object.used || object.string[range->start] == object.string[item_first]) {
-              quoted_is = F_true;
+              flag_fl |= ___fl_flag_is_quoted___;
             }
             else if (f_fss_is_space(object, *range, state) == F_true) {
-              quoted_is = F_true;
+              flag_fl |= ___fl_flag_is_quoted___;
             }
             else if (F_status_is_error(state->status)) {
               break;
@@ -1128,13 +1198,13 @@ extern "C" {
             if (F_status_is_error(state->status)) break;
           }
           else {
-            quoted_is = F_true;
+            flag_fl |= ___fl_flag_is_quoted___;
           }
         }
 
         width = macro_f_utf_byte_width(object.string[range->start]);
 
-        state->status = f_memory_array_increase_by(width, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
+        state->status = f_memory_array_increase_by(width + 3, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
         if (F_status_is_error(state->status)) break;
 
         memcpy(destination->string + destination->used, object.string + range->start, width);
@@ -1146,27 +1216,36 @@ extern "C" {
       if (F_status_is_error(state->status)) break;
     } // for
 
-    if (F_status_is_error(state->status)) {
-      destination->used = used_start;
+    if (F_status_is_error_not(state->status) && (flag_fl & ___fl_flag_save_partial___)) {
+      if (range->start > range->stop || range->start >= object.used) {
+        if (partial.start <= partial.stop) {
+          state->status = f_memory_array_increase_by((partial.stop - partial.start) + 4, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
 
-      return;
+          if (F_status_is_error_not(state->status)) {
+            flag_fl |= ___fl_flag_has_increased___;
+
+            state->status = f_string_dynamic_partial_append_nulless(object, partial, destination);
+          }
+        }
+      }
     }
 
-    if (quoted_is) {
-      state->status = f_memory_array_increase_by(state->step_small + 2, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
+    if (F_status_is_error_not(state->status) && (flag_fl & ___fl_flag_is_quoted___) && !(flag_fl & ___fl_flag_has_increased___)) {
+      state->status = f_memory_array_increase_by(state->step_small + 3, sizeof(f_char_t), (void **) &destination->string, &destination->used, &destination->size);
+    }
 
-      if (F_status_is_error(state->status)) {
-        destination->used = used_start;
+    if (F_status_is_error(state->status)) {
+      destination->used = used_start;
 
-        return;
-      }
+      return;
+    }
 
+    if (flag_fl & ___fl_flag_is_quoted___) {
       destination->string[used_start] = quote_char;
       destination->string[destination->used++] = quote_char;
 
-      // The start quote may or may not need to be delimited in this case.
+      // The start quote may or may not need to be delimited in this case. // TODO: save start quote position? Review this logic.
       if (destination->string[input_start] == quote_char) {
-        // TODO: Verify no combining joiners following.
         for (i = input_start + macro_f_utf_byte_width(object.string[input_start]); i <= range->stop && i < object.used; i += macro_f_utf_byte_width(object.string[i])) {
 
           if (state->interrupt) {
@@ -1218,6 +1297,13 @@ extern "C" {
     #undef ___fl_flag_as_object___
 
     #undef ___fl_flag_do_handle___
+    #undef ___fl_flag_has_combining___
+    #undef ___fl_flag_has_combining_joiner___
+    #undef ___fl_flag_has_increased___
+    #undef ___fl_flag_has_joiner___
+    #undef ___fl_flag_is_quoted___
+    #undef ___fl_flag_is_commented___
+    #undef ___fl_flag_save_partial___
   }
 #endif // !defined(_di_fl_fss_basic_content_read_) || !defined(_di_fl_fss_basic_object_write_) || !defined(_di_fl_fss_extended_object_write_) || !defined(_di_fl_fss_extended_content_read_) || !defined(_di_fl_fss_extended_content_write_) || !defined(_di_fl_fss_payload_header_map_)
 
diff --git a/level_1/fl_fss/c/private-fss.h b/level_1/fl_fss/c/private-fss.h
index c1cf9173c..f85248402 100644
--- a/level_1/fl_fss/c/private-fss.h
+++ b/level_1/fl_fss/c/private-fss.h
@@ -83,6 +83,7 @@ extern "C" {
  *     Errors (with error bit) from: f_fss_is_zero_width().
  *     Errors (with error bit) from: f_fss_skip_past_delimit().
  *     Errors (with error bit) from: f_fss_skip_past_space().
+ *     Errors (with error bit) from: f_utf_buffer_decrement().
  *     Errors (with error bit) from: f_utf_buffer_increment().
  *     Errors (with error bit) from: f_utf_is_combining_joiner().
  *
@@ -97,6 +98,7 @@ extern "C" {
  * @see f_fss_is_zero_width()
  * @see f_fss_skip_past_delimit()
  * @see f_fss_skip_past_space()
+ * @see f_utf_buffer_decrement()
  * @see f_utf_buffer_increment()
  * @see f_utf_is_combining_joiner()
  * @see fl_fss_basic_object_read()
-- 
2.52.0