GuString is now an ordinary C string - it makes live easier. In addition PgfSymbolKS, PgfExprFun and PgfLiteralStr now keep their strings as embedded flexible arrays. The latest change gives us the same compactness as the old representation but it is a lot easier to use.

src/runtime/c/gu/map.c

@@ -4,11 +4,13 @@
 #include <gu/map.h>
 #include <gu/assert.h>
 #include <gu/prime.h>
+#include <gu/string.h>
 
 typedef enum {
 	GU_MAP_GENERIC,
 	GU_MAP_ADDR,
-	GU_MAP_WORD
+	GU_MAP_WORD,
+	GU_MAP_STRING
 } GuMapKind;
 
 typedef struct GuMapData GuMapData;
@@ -66,6 +68,9 @@ gu_map_entry_is_free(GuMap* map, GuMapData* data, size_t idx)
 	} else if (map->kind == GU_MAP_WORD) {
 		GuWord key = ((GuWord*)data->keys)[idx];
 		return key == 0;
+	} else if (map->kind == GU_MAP_STRING) {
+		GuString key = ((GuString*)data->keys)[idx];
+		return key == NULL;
 	}
 	gu_assert(map->kind == GU_MAP_GENERIC);
 	const void* key = &data->keys[idx * map->key_size];
@@ -137,6 +142,27 @@ gu_map_lookup(GuMap* map, const void* key, size_t* idx_out)
 		gu_impossible();
 		break;
 	}
+	case GU_MAP_STRING: {
+		GuHasher* hasher = map->hasher;
+		GuEquality* eq = (GuEquality*) hasher;
+		GuHash hash = hasher->hash(hasher, key);
+		size_t idx = hash % n;
+		size_t offset = (hash % (n - 2)) + 1;
+		while (true) {
+			GuString entry_key =
+				((GuString*)map->data.keys)[idx];
+			if (entry_key == NULL && map->data.zero_idx != idx) {
+				*idx_out = idx;
+				return false;
+			} else if (eq->is_equal(eq, key, entry_key)) {
+				*idx_out = idx;
+				return true;
+			}
+			idx = (idx + offset) % n;
+		}
+		gu_impossible();
+		break;
+	}
 	default:
 		gu_impossible();
 	}
@@ -179,6 +205,11 @@ gu_map_resize(GuMap* map)
 			((const void**)data->keys)[i] = NULL;
 		}
 		break;
+	case GU_MAP_STRING:
+		for (size_t i = 0; i < data->n_entries; i++) {
+			((GuString*)data->keys)[i] = NULL;
+		}
+		break;
 	default:
 		gu_impossible();
 	}
@@ -195,6 +226,8 @@ gu_map_resize(GuMap* map)
 		void* old_key = &old_data.keys[i * key_size];
 		if (map->kind == GU_MAP_ADDR) {
 			old_key = *(void**)old_key;
+		} else if (map->kind == GU_MAP_STRING) {
+			old_key = (void*) *(GuString*)old_key;
 		}
 		void* old_value = &old_data.values[i * value_size];
 
@@ -268,6 +301,8 @@ gu_map_insert(GuMap* map, const void* key)
 		}
 		if (map->kind == GU_MAP_ADDR) {
 			((const void**)map->data.keys)[idx] = key;
+		} else if (map->kind == GU_MAP_STRING) {
+			((GuString*)map->data.keys)[idx] = key;
 		} else {
 			memcpy(&map->data.keys[idx * map->key_size],
 			       key, map->key_size);
@@ -296,6 +331,8 @@ gu_map_iter(GuMap* map, GuMapItor* itor, GuExn* err)
 		void* value = &map->data.values[i * map->value_size];
 		if (map->kind == GU_MAP_ADDR) {
 			key = *(const void* const*) key;
+		} else if (map->kind == GU_MAP_STRING) {
+			key = *(GuString*) key;
 		}
 		itor->fn(itor, key, value, err);
 	}
@@ -323,8 +360,10 @@ gu_map_enum_next(GuEnum* self, void* to, GuPool* pool)
 		en->x.value = &en->ht->data.values[i * en->ht->value_size];
 		if (en->ht->kind == GU_MAP_ADDR) {
 			en->x.key = *(const void* const*) en->x.key;
+		} else if (en->ht->kind == GU_MAP_STRING) {
+			en->x.key = *(GuString*) en->x.key;
 		}
-		
+
 		*((GuMapKeyValue**) to) = &en->x;
 		break;
 	}
@@ -365,10 +404,12 @@ gu_make_map(size_t key_size, GuHasher* hasher,
 	GuMapKind kind =
 		((!hasher || hasher == gu_addr_hasher)
 		 ? GU_MAP_ADDR
+		 : (hasher == gu_string_hasher)
+		 ? GU_MAP_STRING
 		 : (key_size == sizeof(GuWord) && hasher == gu_word_hasher)
 		 ? GU_MAP_WORD
 		 : GU_MAP_GENERIC);
-	if (kind == GU_MAP_ADDR) {
+	if (kind == GU_MAP_ADDR || kind == GU_MAP_STRING) {
 		key_size = sizeof(GuWord);
 	}
 	GuMapData data = {