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typedef struct {
struct Block *scope; /* NULL for file scope */
struct Declaration *decl;
} IdentDecl;
/*
The way you search an identifier in a tree is:
root.children[low part of 1st char].children[high part of 1st char]
.children[low part of 2nd char]...
*/
#define TREE_NCHILDREN 16
typedef struct IdentTree {
/* zero value is an empty trie */
uint16_t depth;
unsigned char index_in_parent; /* index of this in .parent.children */
struct IdentTree *parent;
struct IdentTree *children[TREE_NCHILDREN];
Array decls; /* array of declarations of this identifier */
} IdentTree;
typedef IdentTree *Identifier;
typedef struct {
BlockArr trees;
IdentTree *root;
} Identifiers;
#if CHAR_MAX - CHAR_MIN > 255
#error "Currently only systems with 8-bit characters can compile toc."
/* TODO: maybe do a run-time error for large characters? */
#endif
/* can this character be used in an identifier? */
static int isident(int c) {
if (c >= 'a' && c <= 'z')
return 1;
if (c >= 'A' && c <= 'Z')
return 1;
if (c >= '0' && c <= '9')
return 1;
if (c == '_') return 1;
#if CHAR_MIN < 0
if (c < 0) /* on systems where char = signed char, UTF-8 characters are probably < 0? */
return 1;
#endif
if (c > 127) /* UTF-8 */
return 1;
return 0;
}
/* used internally to allocate identifiers */
static Identifier ident_new(Identifiers *ids, Identifier parent, unsigned char index_in_parent) {
IdentTree *tree = block_arr_add(&ids->trees);
memset(tree, 0, sizeof *tree); /* use zero value of IdentTree */
#ifdef NONZERO_NULL_PTRS
tree->parent = NULL;
for (size_t i = 0; i < TREE_NCHILDREN; i++)
tree->children[i] = NULL;
tree->decls.data = NULL;
#endif
tree->parent = parent;
if (parent)
tree->depth = (uint16_t)(parent->depth + 1);
tree->index_in_parent = index_in_parent;
return tree;
}
/* Initialize Identifiers. */
static void idents_create(Identifiers *ids) {
block_arr_create(&ids->trees, 10, sizeof(IdentTree)); /* blocks of 1 << 10 = 1024 */
ids->root = ident_new(ids, NULL, 0); /* create root tree */
}
#if CHAR_MIN < 0
#define ident_char_to_uchar(c) ((c) < 0 ? (256 + (c)) : (c))
#else
#define ident_char_to_uchar(c) (c)
#endif
#if CHAR_MIN < 0
#define ident_uchar_to_char(c) ((c) > 127 ? ((c) - 256) : (c))
#else
#define ident_uchar_to_char(c) (c)
#endif
/* 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 *tree = ids->root;
while (1) {
if (!isident(**s)) {
return tree;
}
int c = ident_char_to_uchar(**s);
assert(c >= 0 && c <= 255);
unsigned char c_low = (unsigned char)(c & 0xf);
unsigned char c_high = (unsigned char)(c >> 4);
if (!tree->children[c_low]) {
tree->children[c_low] = ident_new(ids, tree, c_low);
}
tree = tree->children[c_low];
if (!tree->children[c_high]) {
tree->children[c_high] = ident_new(ids, tree, c_high);
}
tree = tree->children[c_high];
(*s)++;
}
}
static void fprint_ident(FILE *out, Identifier id) {
assert(id);
if (id->parent == NULL) return; /* at root */
fprint_ident(out, id->parent->parent); /* to go up one character, we need to go to the grandparent */
int c_low = id->parent->index_in_parent;
int c_high = id->index_in_parent;
int c = ident_uchar_to_char(c_low + (c_high << 4));
fputc(c, out);
}
/* reduced charset = a-z, A-Z, 0-9, _ */
static void fprint_ident_reduced_charset(FILE *out, Identifier id) {
assert(id);
if (id->parent == NULL) return; /* at root */
fprint_ident_reduced_charset(out, id->parent->parent); /* to go up one character, we need to go to the grandparent */
int c_low = id->parent->index_in_parent;
int c_high = id->index_in_parent;
int c = c_low + (c_high << 4);
if (c > 127) {
fprintf(out, "x__%x",c);
} else {
char chr = (char)ident_uchar_to_char(c);
fputc(chr, out);
}
}
/* NULL = no such identifier */
static Identifier ident_get(Identifiers *ids, const char *s) {
IdentTree *tree = ids->root;
while (*s) {
int c = ident_char_to_uchar(*s);
assert(c >= 0 && c <= 255);
unsigned char c_low = (unsigned char)(c & 0xf);
unsigned char c_high = (unsigned char)(c >> 4);
tree = tree->children[c_low];
if (!tree) return NULL;
tree = tree->children[c_high];
if (!tree) return NULL;
s++;
}
return tree;
}
static char *ident_to_str(Identifier i) {
size_t i_len = (size_t)(i->depth / 2); /* length = depth / 2 */
char *str = err_malloc(i_len + 1);
str += i_len;
*str = 0;
while (i->parent) {
str--;
unsigned char c_high = i->index_in_parent;
unsigned char c_low = i->parent->index_in_parent;
char c = (char)ident_uchar_to_char((int)c_low + ((int)c_high << 4));
*str = c;
i = i->parent->parent; /* go to grandparent (prev char) */
}
return str;
}
static void ident_add_decl(Identifier i, struct Declaration *d, struct Block *b) {
if (!i->decls.item_sz) {
arr_create(&i->decls, sizeof(IdentDecl));
}
IdentDecl *id_decl = arr_add(&i->decls);
id_decl->decl = d;
id_decl->scope = b;
}
static IdentDecl *ident_decl(Identifier i) {
return i->decls.item_sz == 0 ? NULL : (IdentDecl*)arr_last(&i->decls);
}
static void ident_tree_free(IdentTree *id) {
if (!id) return;
arr_free(&id->decls);
for (int i = 0; i < TREE_NCHILDREN; i++)
ident_tree_free(id->children[i]);
}
static void idents_free(Identifiers *ids) {
ident_tree_free(ids->root);
block_arr_free(&ids->trees);
}
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