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/* OPTIM: This is not ideal. There should be one dynamic array of tree nodes. */
typedef struct {
struct Block *scope; /* NULL for file scope */
struct Declaration *decl;
} IdentDecl;
typedef struct IdentTree {
/* zero value is an empty trie */
long id;
int len; /* length of identifier = depth in tree */
struct IdentTree *children;
struct IdentTree *parent;
Array decls; /* array of declarations of this identifier */
unsigned long c_fn_reps; /* number of repetitions of this identifier in the C output--only used for functions */
size_t depth;
} IdentTree;
typedef IdentTree *Identifier;
/* MUST be zero-initialized before use */
typedef struct {
IdentTree tree_root;
long curr_id;
} Identifiers;
static const char identifier_chars[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_";
#define NIDENTIFIER_CHARS ((int)((sizeof identifier_chars) - 1)) /* -1 for null char */
/* returns -1 if c is not a valid identifier character, its index in identifier_chars otherwise */
static int ident_char_index(int c) {
if (c >= 'a' && c <= 'z')
return c - 'a';
if (c >= 'A' && c <= 'Z')
return c - 'A' + 26;
if (c >= '0' && c <= '9')
return c - '0' + 52;
if (c == '_') return 62;
return -1;
}
/* can this character be used in an identifier? */
static int isident(int c) {
return ident_char_index(c) != -1; /* OPTIM: Write separate function */
}
/* moves s to the char after the identifier */
/* inserts if does not exist. reads until non-ident char is found. */
/* advances past identifier */
static Identifier ident_insert(Identifiers *ids, char **s) {
IdentTree *t = &ids->tree_root;
while (1) {
char c = **s;
if (!isident(c)) {
if (t->id == 0) t->id = ++ids->curr_id;
return t;
}
if (!t->children) {
/* allocate children */
t->children = err_calloc(NIDENTIFIER_CHARS, sizeof *t->children);
for (int i = 0; i < NIDENTIFIER_CHARS; i++) {
t->children[i].parent = t; /* child's parent = self */
t->children[i].depth = t->depth + 1;
}
}
t = &t->children[ident_char_index(c)];
(*s)++;
}
}
static void fprint_ident(FILE *out, Identifier id) {
if (id->parent == NULL) return; /* at root */
/* OPTIM: Use malloc(id->len)???? would probably use less mem for long idents, but
it's on the heap */
fprint_ident(out, id->parent);
fputc(identifier_chars[id - id->parent->children /* index of self in parent */], out);
}
static bool ident_eq_str(Identifier i, const char *s) {
size_t len = strlen(s);
if (i->depth != len) return false;
s += len - 1;
while (i->parent != NULL) {
if (identifier_chars[i - i->parent->children /* index of self in parent */] != *s)
return false;
i = i->parent;
if (i->parent != NULL)
s--;
}
return true;
}
static char *ident_to_str(Identifier i) {
char *str = malloc(i->depth + 1);
str += i->depth;
*str = 0;
while (i->parent != NULL) {
str--;
*str = identifier_chars[i - i->parent->children];
i = i->parent;
}
return str;
}
static IdentDecl *ident_decl(Identifier i) {
return (IdentDecl*)arr_last(&i->decls);
}
static void idents_free_tree(IdentTree *tree) {
if (!tree->children) return;
for (int i = 0; i < NIDENTIFIER_CHARS; i++)
idents_free_tree(&tree->children[i]);
free(tree->children);
}
static void idents_free(Identifiers *ids) {
idents_free_tree(&ids->tree_root);
}
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