input: Accept short compose sequences

Some of the X keyboard layouts use compose
sequences of length one to make individual
keys generate multiple Unicode characters.

To support this use case, change the index
part of the table format to also include
an offset for length 1. Bump the table
version to indicate this change.

Fixes: #5172

1 files changed, 22 insertions, 30 deletions

diff --git a/gtk/gtkcomposetable.c b/gtk/gtkcomposetable.c
index eda1e5ad5b..c344d947da 100644
--- a/gtk/gtkcomposetable.c
+++ b/gtk/gtkcomposetable.c
@@ -28,7 +28,7 @@
 
 
 #define GTK_COMPOSE_TABLE_MAGIC "GtkComposeTable"
-#define GTK_COMPOSE_TABLE_VERSION (3)
+#define GTK_COMPOSE_TABLE_VERSION (4)
 
 extern const GtkComposeTable builtin_compose_table;
 
@@ -504,12 +504,6 @@ parser_remove_duplicates (GtkComposeParser *parser)
           goto next;
         }
 
-      if (sequence[1] == 0)
-        {
-          remove_sequence = TRUE;
-          goto next;
-        }
-
       for (i = 0; i < MAX_COMPOSE_LEN + 1; i++)
         keysyms[i] = 0;
 
@@ -907,7 +901,7 @@ parser_get_compose_table (GtkComposeParser *parser)
                                      (GCompareDataFunc) sequence_compare,
                                      NULL);
 
-  index_rowstride = max_compose_len + 1;
+  index_rowstride = max_compose_len + 2;
   data = g_new0 (guint16, n_first * index_rowstride + size);
 
   char_data = g_string_new ("");
@@ -923,7 +917,7 @@ parser_get_compose_table (GtkComposeParser *parser)
       char *value = g_hash_table_lookup (parser->sequences, sequence);
       int len = sequence_length (sequence);
 
-      g_assert (2 <= len && len <= max_compose_len);
+      g_assert (1 <= len && len <= max_compose_len);
 
       /* Encode the value. If the value is a single
        * character with a value smaller than 1 << 15,
@@ -979,10 +973,10 @@ parser_get_compose_table (GtkComposeParser *parser)
 
       rest_pos += len;
 
-      for (i = len; i <= max_compose_len; i++)
+      for (i = len + 1; i < index_rowstride; i++)
         data[first_pos + i] = rest_pos;
 
-      for (i = 1; i < max_compose_len; i++)
+      for (i = 1; i + 1 < index_rowstride; i++)
         g_assert (data[first_pos + i] <= data[first_pos + i + 1]);
     }
 
@@ -1275,7 +1269,7 @@ gtk_compose_table_check (const GtkComposeTable *table,
                          gboolean              *compose_match,
                          GString               *output)
 {
-  int row_stride;
+  int len;
   guint16 *seq_index;
   guint16 *seq;
   int i;
@@ -1297,7 +1291,7 @@ gtk_compose_table_check (const GtkComposeTable *table,
   seq_index = bsearch (compose_buffer,
                        table->data,
                        table->n_index_size,
-                       sizeof (guint16) * (table->max_seq_len + 1),
+                       sizeof (guint16) * (table->max_seq_len + 2),
                        compare_seq_index);
 
   if (!seq_index)
@@ -1312,21 +1306,21 @@ gtk_compose_table_check (const GtkComposeTable *table,
 
   for (i = n_compose - 1; i < table->max_seq_len; i++)
     {
-      row_stride = i + 1;
+      len = i + 1;
 
-      if (seq_index[i + 1] - seq_index[i] > 0)
+      if (seq_index[len + 1] - seq_index[len] > 0)
         {
           seq = bsearch (compose_buffer + 1,
-                         table->data + seq_index[i],
-                         (seq_index[i + 1] - seq_index[i]) / row_stride,
-                         sizeof (guint16) * row_stride,
+                         table->data + seq_index[len],
+                         (seq_index[len + 1] - seq_index[len]) / len,
+                         sizeof (guint16) * len,
                          compare_seq);
 
           if (seq)
             {
               if (i == n_compose - 1)
                 {
-                  value = seq[row_stride - 1];
+                  value = seq[len - 1];
 
                   if ((value & (1 << 15)) != 0)
                     g_string_append (output, &table->char_data[value & ~(1 << 15)]);
@@ -1367,7 +1361,7 @@ gtk_compose_table_get_prefix (const GtkComposeTable *table,
                               int                    n_compose,
                               int                   *prefix)
 {
-  int index_stride = table->max_seq_len + 1;
+  int index_stride = table->max_seq_len + 2;
   int p = 0;
 
   for (int idx = 0; idx < table->n_index_size; idx++)
@@ -1378,9 +1372,9 @@ gtk_compose_table_get_prefix (const GtkComposeTable *table,
         {
           p = 1;
 
-          for (int i = 1; i < table->max_seq_len; i++)
+          for (int i = 1; i < table->max_seq_len + 1; i++)
             {
-              int len = i + 1;
+              int len = i;
 
               for (int j = seq_index[i]; j < seq_index[i + 1]; j += len)
                 {
@@ -1407,20 +1401,20 @@ gtk_compose_table_foreach (const GtkComposeTable      *table,
                            GtkComposeSequenceCallback  callback,
                            gpointer                    data)
 {
-  int index_stride = table->max_seq_len + 1;
+  int index_stride = table->max_seq_len + 2;
   gunichar *sequence;
   int seqno;
 
-  sequence = g_new0 (gunichar, table->max_seq_len + 1);
+  sequence = g_newa (gunichar, table->max_seq_len + 1);
 
   seqno = 0;
   for (int idx = 0; idx < table->n_index_size; idx++)
     {
       const guint16 *seq_index = table->data + (idx * index_stride);
 
-      for (int i = 1; i < table->max_seq_len; i++)
+      for (int i = 1; i <= table->max_seq_len; i++)
         {
-          int len = i + 1;
+          int len = i;
 
           g_assert (seq_index[i] <= seq_index[i + 1]);
           g_assert (seq_index[i + 1] <= table->data_size);
@@ -1433,8 +1427,8 @@ gtk_compose_table_foreach (const GtkComposeTable      *table,
               char *value;
 
               sequence[0] = seq_index[0];
-              for (int k = 0; k < len - 1; k++)
-                sequence[k + 1] = (gunichar) table->data[j + k];
+              for (int k = 1; k < len; k++)
+                sequence[k] = (gunichar) table->data[j + k - 1];
               sequence[len] = 0;
 
               encoded_value = table->data[j + len - 1];
@@ -1456,8 +1450,6 @@ gtk_compose_table_foreach (const GtkComposeTable      *table,
             }
         }
     }
-
-  g_free (sequence);
 }
 
 /* Checks if a keysym is a dead key.