storm/w3m
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
Files
74a537f811b89b1b31ba37bf476dd1aaf0de8ed3
w3m/gc/cord/cordbscs.c
Akinori Ito 68a07bf03b Initial revision
2001-11-08 05:14:08 +00:00

916 lines
26 KiB
C
Raw Blame History

/*
* Copyright (c) 1993-1994 by Xerox Corporation. All rights reserved.
*
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
*
* Permission is hereby granted to use or copy this program
* for any purpose, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*
* Author: Hans-J. Boehm (boehm@parc.xerox.com)
*/
/* Boehm, October 3, 1994 5:19 pm PDT */
# include "gc.h"
# include "cord.h"
# include <stdlib.h>
# include <stdio.h>
# include <string.h>
/* An implementation of the cord primitives. These are the only */
/* Functions that understand the representation. We perform only */
/* minimal checks on arguments to these functions. Out of bounds */
/* arguments to the iteration functions may result in client functions */
/* invoked on garbage data. In most cases, client functions should be */
/* programmed defensively enough that this does not result in memory */
/* smashes. */
typedef void (* oom_fn)(void);
oom_fn CORD_oom_fn = (oom_fn) 0;
# define OUT_OF_MEMORY { if (CORD_oom_fn != (oom_fn) 0) (*CORD_oom_fn)(); \
ABORT("Out of memory\n"); }
# define ABORT(msg) { fprintf(stderr, "%s\n", msg); abort(); }
typedef unsigned long word;
typedef union {
struct Concatenation {
char null;
char header;
char depth; /* concatenation nesting depth. */
unsigned char left_len;
/* Length of left child if it is sufficiently */
/* short; 0 otherwise. */
# define MAX_LEFT_LEN 255
word len;
CORD left; /* length(left) > 0 */
CORD right; /* length(right) > 0 */
} concatenation;
struct Function {
char null;
char header;
char depth; /* always 0 */
char left_len; /* always 0 */
word len;
CORD_fn fn;
void * client_data;
} function;
struct Generic {
char null;
char header;
char depth;
char left_len;
word len;
} generic;
char string[1];
} CordRep;
# define CONCAT_HDR 1
# define FN_HDR 4
# define SUBSTR_HDR 6
/* Substring nodes are a special case of function nodes. */
/* The client_data field is known to point to a substr_args */
/* structure, and the function is either CORD_apply_access_fn */
/* or CORD_index_access_fn. */
/* The following may be applied only to function and concatenation nodes: */
#define IS_CONCATENATION(s) (((CordRep *)s)->generic.header == CONCAT_HDR)
#define IS_FUNCTION(s) ((((CordRep *)s)->generic.header & FN_HDR) != 0)
#define IS_SUBSTR(s) (((CordRep *)s)->generic.header == SUBSTR_HDR)
#define LEN(s) (((CordRep *)s) -> generic.len)
#define DEPTH(s) (((CordRep *)s) -> generic.depth)
#define GEN_LEN(s) (CORD_IS_STRING(s) ? strlen(s) : LEN(s))
#define LEFT_LEN(c) ((c) -> left_len != 0? \
(c) -> left_len \
: (CORD_IS_STRING((c) -> left) ? \
(c) -> len - GEN_LEN((c) -> right) \
: LEN((c) -> left)))
#define SHORT_LIMIT (sizeof(CordRep) - 1)
/* Cords shorter than this are C strings */
/* Dump the internal representation of x to stdout, with initial */
/* indentation level n. */
void CORD_dump_inner(CORD x, unsigned n)
{
register size_t i;
for (i = 0; i < (size_t)n; i++) {
fputs(" ", stdout);
}
if (x == 0) {
fputs("NIL\n", stdout);
} else if (CORD_IS_STRING(x)) {
for (i = 0; i <= SHORT_LIMIT; i++) {
if (x[i] == '\0') break;
putchar(x[i]);
}
if (x[i] != '\0') fputs("...", stdout);
putchar('\n');
} else if (IS_CONCATENATION(x)) {
register struct Concatenation * conc =
&(((CordRep *)x) -> concatenation);
printf("Concatenation: %p (len: %d, depth: %d)\n",
x, (int)(conc -> len), (int)(conc -> depth));
CORD_dump_inner(conc -> left, n+1);
CORD_dump_inner(conc -> right, n+1);
} else /* function */{
register struct Function * func =
&(((CordRep *)x) -> function);
if (IS_SUBSTR(x)) printf("(Substring) ");
printf("Function: %p (len: %d): ", x, (int)(func -> len));
for (i = 0; i < 20 && i < func -> len; i++) {
putchar((*(func -> fn))(i, func -> client_data));
}
if (i < func -> len) fputs("...", stdout);
putchar('\n');
}
}
/* Dump the internal representation of x to stdout */
void CORD_dump(CORD x)
{
CORD_dump_inner(x, 0);
fflush(stdout);
}
CORD CORD_cat_char_star(CORD x, const char * y, size_t leny)
{
register size_t result_len;
register size_t lenx;
register int depth;
if (x == CORD_EMPTY) return(y);
if (leny == 0) return(x);
if (CORD_IS_STRING(x)) {
lenx = strlen(x);
result_len = lenx + leny;
if (result_len <= SHORT_LIMIT) {
register char * result = GC_MALLOC_ATOMIC(result_len+1);
if (result == 0) OUT_OF_MEMORY;
memcpy(result, x, lenx);
memcpy(result + lenx, y, leny);
result[result_len] = '\0';
return((CORD) result);
} else {
depth = 1;
}
} else {
register CORD right;
register CORD left;
register char * new_right;
register size_t right_len;
lenx = LEN(x);
if (leny <= SHORT_LIMIT/2
&& IS_CONCATENATION(x)
&& CORD_IS_STRING(right = ((CordRep *)x) -> concatenation.right)) {
/* Merge y into right part of x. */
if (!CORD_IS_STRING(left = ((CordRep *)x) -> concatenation.left)) {
right_len = lenx - LEN(left);
} else if (((CordRep *)x) -> concatenation.left_len != 0) {
right_len = lenx - ((CordRep *)x) -> concatenation.left_len;
} else {
right_len = strlen(right);
}
result_len = right_len + leny; /* length of new_right */
if (result_len <= SHORT_LIMIT) {
new_right = GC_MALLOC_ATOMIC(result_len + 1);
memcpy(new_right, right, right_len);
memcpy(new_right + right_len, y, leny);
new_right[result_len] = '\0';
y = new_right;
leny = result_len;
x = left;
lenx -= right_len;
/* Now fall through to concatenate the two pieces: */
}
if (CORD_IS_STRING(x)) {
depth = 1;
} else {
depth = DEPTH(x) + 1;
}
} else {
depth = DEPTH(x) + 1;
}
result_len = lenx + leny;
}
{
/* The general case; lenx, result_len is known: */
register struct Concatenation * result;
result = GC_NEW(struct Concatenation);
if (result == 0) OUT_OF_MEMORY;
result->header = CONCAT_HDR;
result->depth = depth;
if (lenx <= MAX_LEFT_LEN) result->left_len = lenx;
result->len = result_len;
result->left = x;
result->right = y;
if (depth > MAX_DEPTH) {
return(CORD_balance((CORD)result));
} else {
return((CORD) result);
}
}
}
CORD CORD_cat(CORD x, CORD y)
{
register size_t result_len;
register int depth;
register size_t lenx;
if (x == CORD_EMPTY) return(y);
if (y == CORD_EMPTY) return(x);
if (CORD_IS_STRING(y)) {
return(CORD_cat_char_star(x, y, strlen(y)));
} else if (CORD_IS_STRING(x)) {
lenx = strlen(x);
depth = DEPTH(y) + 1;
} else {
register int depthy = DEPTH(y);
lenx = LEN(x);
depth = DEPTH(x) + 1;
if (depthy >= depth) depth = depthy + 1;
}
result_len = lenx + LEN(y);
{
register struct Concatenation * result;
result = GC_NEW(struct Concatenation);
if (result == 0) OUT_OF_MEMORY;
result->header = CONCAT_HDR;
result->depth = depth;
if (lenx <= MAX_LEFT_LEN) result->left_len = lenx;
result->len = result_len;
result->left = x;
result->right = y;
return((CORD) result);
}
}
CORD CORD_from_fn(CORD_fn fn, void * client_data, size_t len)
{
if (len <= 0) return(0);
if (len <= SHORT_LIMIT) {
register char * result;
register size_t i;
char buf[SHORT_LIMIT+1];
register char c;
for (i = 0; i < len; i++) {
c = (*fn)(i, client_data);
if (c == '\0') goto gen_case;
buf[i] = c;
}
buf[i] = '\0';
result = GC_MALLOC_ATOMIC(len+1);
if (result == 0) OUT_OF_MEMORY;
strcpy(result, buf);
result[len] = '\0';
return((CORD) result);
}
gen_case:
{
register struct Function * result;
result = GC_NEW(struct Function);
if (result == 0) OUT_OF_MEMORY;
result->header = FN_HDR;
/* depth is already 0 */
result->len = len;
result->fn = fn;
result->client_data = client_data;
return((CORD) result);
}
}
size_t CORD_len(CORD x)
{
if (x == 0) {
return(0);
} else {
return(GEN_LEN(x));
}
}
struct substr_args {
CordRep * sa_cord;
size_t sa_index;
};
char CORD_index_access_fn(size_t i, void * client_data)
{
register struct substr_args *descr = (struct substr_args *)client_data;
return(((char *)(descr->sa_cord))[i + descr->sa_index]);
}
char CORD_apply_access_fn(size_t i, void * client_data)
{
register struct substr_args *descr = (struct substr_args *)client_data;
register struct Function * fn_cord = &(descr->sa_cord->function);
return((*(fn_cord->fn))(i + descr->sa_index, fn_cord->client_data));
}
/* A version of CORD_substr that simply returns a function node, thus */
/* postponing its work. The fourth argument is a function that may */
/* be used for efficient access to the ith character. */
/* Assumes i >= 0 and i + n < length(x). */
CORD CORD_substr_closure(CORD x, size_t i, size_t n, CORD_fn f)
{
register struct substr_args * sa = GC_NEW(struct substr_args);
CORD result;
if (sa == 0) OUT_OF_MEMORY;
sa->sa_cord = (CordRep *)x;
sa->sa_index = i;
result = CORD_from_fn(f, (void *)sa, n);
((CordRep *)result) -> function.header = SUBSTR_HDR;
return (result);
}
# define SUBSTR_LIMIT (10 * SHORT_LIMIT)
/* Substrings of function nodes and flat strings shorter than */
/* this are flat strings. Othewise we use a functional */
/* representation, which is significantly slower to access. */
/* A version of CORD_substr that assumes i >= 0, n > 0, and i + n < length(x).*/
CORD CORD_substr_checked(CORD x, size_t i, size_t n)
{
if (CORD_IS_STRING(x)) {
if (n > SUBSTR_LIMIT) {
return(CORD_substr_closure(x, i, n, CORD_index_access_fn));
} else {
register char * result = GC_MALLOC_ATOMIC(n+1);
if (result == 0) OUT_OF_MEMORY;
strncpy(result, x+i, n);
result[n] = '\0';
return(result);
}
} else if (IS_CONCATENATION(x)) {
register struct Concatenation * conc
= &(((CordRep *)x) -> concatenation);
register size_t left_len;
register size_t right_len;
left_len = LEFT_LEN(conc);
right_len = conc -> len - left_len;
if (i >= left_len) {
if (n == right_len) return(conc -> right);
return(CORD_substr_checked(conc -> right, i - left_len, n));
} else if (i+n <= left_len) {
if (n == left_len) return(conc -> left);
return(CORD_substr_checked(conc -> left, i, n));
} else {
/* Need at least one character from each side. */
register CORD left_part;
register CORD right_part;
register size_t left_part_len = left_len - i;
if (i == 0) {
left_part = conc -> left;
} else {
left_part = CORD_substr_checked(conc -> left, i, left_part_len);
}
if (i + n == right_len + left_len) {
right_part = conc -> right;
} else {
right_part = CORD_substr_checked(conc -> right, 0,
n - left_part_len);
}
return(CORD_cat(left_part, right_part));
}
} else /* function */ {
if (n > SUBSTR_LIMIT) {
if (IS_SUBSTR(x)) {
/* Avoid nesting substring nodes. */
register struct Function * f = &(((CordRep *)x) -> function);
register struct substr_args *descr =
(struct substr_args *)(f -> client_data);
return(CORD_substr_closure((CORD)descr->sa_cord,
i + descr->sa_index,
n, f -> fn));
} else {
return(CORD_substr_closure(x, i, n, CORD_apply_access_fn));
}
} else {
char * result;
register struct Function * f = &(((CordRep *)x) -> function);
char buf[SUBSTR_LIMIT+1];
register char * p = buf;
register char c;
register int j;
register int lim = i + n;
for (j = i; j < lim; j++) {
c = (*(f -> fn))(j, f -> client_data);
if (c == '\0') {
return(CORD_substr_closure(x, i, n, CORD_apply_access_fn));
}
*p++ = c;
}
*p = '\0';
result = GC_MALLOC_ATOMIC(n+1);
if (result == 0) OUT_OF_MEMORY;
strcpy(result, buf);
return(result);
}
}
}
CORD CORD_substr(CORD x, size_t i, size_t n)
{
register size_t len = CORD_len(x);
if (i >= len || n <= 0) return(0);
/* n < 0 is impossible in a correct C implementation, but */
/* quite possible under SunOS 4.X. */
if (i + n > len) n = len - i;
# ifndef __STDC__
if (i < 0) ABORT("CORD_substr: second arg. negative");
/* Possible only if both client and C implementation are buggy. */
/* But empirically this happens frequently. */
# endif
return(CORD_substr_checked(x, i, n));
}
/* See cord.h for definition. We assume i is in range. */
int CORD_iter5(CORD x, size_t i, CORD_iter_fn f1,
CORD_batched_iter_fn f2, void * client_data)
{
if (x == 0) return(0);
if (CORD_IS_STRING(x)) {
register const char *p = x+i;
if (*p == '\0') ABORT("2nd arg to CORD_iter5 too big");
if (f2 != CORD_NO_FN) {
return((*f2)(p, client_data));
} else {
while (*p) {
if ((*f1)(*p, client_data)) return(1);
p++;
}
return(0);
}
} else if (IS_CONCATENATION(x)) {
register struct Concatenation * conc
= &(((CordRep *)x) -> concatenation);
if (i > 0) {
register size_t left_len = LEFT_LEN(conc);
if (i >= left_len) {
return(CORD_iter5(conc -> right, i - left_len, f1, f2,
client_data));
}
}
if (CORD_iter5(conc -> left, i, f1, f2, client_data)) {
return(1);
}
return(CORD_iter5(conc -> right, 0, f1, f2, client_data));
} else /* function */ {
register struct Function * f = &(((CordRep *)x) -> function);
register size_t j;
register size_t lim = f -> len;
for (j = i; j < lim; j++) {
if ((*f1)((*(f -> fn))(j, f -> client_data), client_data)) {
return(1);
}
}
return(0);
}
}
#undef CORD_iter
int CORD_iter(CORD x, CORD_iter_fn f1, void * client_data)
{
return(CORD_iter5(x, 0, f1, CORD_NO_FN, client_data));
}
int CORD_riter4(CORD x, size_t i, CORD_iter_fn f1, void * client_data)
{
if (x == 0) return(0);
if (CORD_IS_STRING(x)) {
register const char *p = x + i;
register char c;
for(;;) {
c = *p;
if (c == '\0') ABORT("2nd arg to CORD_riter4 too big");
if ((*f1)(c, client_data)) return(1);
if (p == x) break;
p--;
}
return(0);
} else if (IS_CONCATENATION(x)) {
register struct Concatenation * conc
= &(((CordRep *)x) -> concatenation);
register CORD left_part = conc -> left;
register size_t left_len;
left_len = LEFT_LEN(conc);
if (i >= left_len) {
if (CORD_riter4(conc -> right, i - left_len, f1, client_data)) {
return(1);
}
return(CORD_riter4(left_part, left_len - 1, f1, client_data));
} else {
return(CORD_riter4(left_part, i, f1, client_data));
}
} else /* function */ {
register struct Function * f = &(((CordRep *)x) -> function);
register size_t j;
for (j = i; ; j--) {
if ((*f1)((*(f -> fn))(j, f -> client_data), client_data)) {
return(1);
}
if (j == 0) return(0);
}
}
}
int CORD_riter(CORD x, CORD_iter_fn f1, void * client_data)
{
return(CORD_riter4(x, CORD_len(x) - 1, f1, client_data));
}
/*
* The following functions are concerned with balancing cords.
* Strategy:
* Scan the cord from left to right, keeping the cord scanned so far
* as a forest of balanced trees of exponentialy decreasing length.
* When a new subtree needs to be added to the forest, we concatenate all
* shorter ones to the new tree in the appropriate order, and then insert
* the result into the forest.
* Crucial invariants:
* 1. The concatenation of the forest (in decreasing order) with the
* unscanned part of the rope is equal to the rope being balanced.
* 2. All trees in the forest are balanced.
* 3. forest[i] has depth at most i.
*/
typedef struct {
CORD c;
size_t len; /* Actual length of c */
} ForestElement;
static size_t min_len [ MAX_DEPTH ];
static int min_len_init = 0;
int CORD_max_len;
typedef ForestElement Forest [ MAX_DEPTH ];
/* forest[i].len >= fib(i+1) */
/* The string is the concatenation */
/* of the forest in order of DECREASING */
/* indices. */
void CORD_init_min_len()
{
register int i;
register size_t last, previous, current;
min_len[0] = previous = 1;
min_len[1] = last = 2;
for (i = 2; i < MAX_DEPTH; i++) {
current = last + previous;
if (current < last) /* overflow */ current = last;
min_len[i] = current;
previous = last;
last = current;
}
CORD_max_len = last - 1;
min_len_init = 1;
}
void CORD_init_forest(ForestElement * forest, size_t max_len)
{
register int i;
for (i = 0; i < MAX_DEPTH; i++) {
forest[i].c = 0;
if (min_len[i] > max_len) return;
}
ABORT("Cord too long");
}
/* Add a leaf to the appropriate level in the forest, cleaning */
/* out lower levels as necessary. */
/* Also works if x is a balanced tree of concatenations; however */
/* in this case an extra concatenation node may be inserted above x; */
/* This node should not be counted in the statement of the invariants. */
void CORD_add_forest(ForestElement * forest, CORD x, size_t len)
{
register int i = 0;
register CORD sum = CORD_EMPTY;
register size_t sum_len = 0;
while (len > min_len[i + 1]) {
if (forest[i].c != 0) {
sum = CORD_cat(forest[i].c, sum);
sum_len += forest[i].len;
forest[i].c = 0;
}
i++;
}
/* Sum has depth at most 1 greter than what would be required */
/* for balance. */
sum = CORD_cat(sum, x);
sum_len += len;
/* If x was a leaf, then sum is now balanced. To see this */
/* consider the two cases in which forest[i-1] either is or is */
/* not empty. */
while (sum_len >= min_len[i]) {
if (forest[i].c != 0) {
sum = CORD_cat(forest[i].c, sum);
sum_len += forest[i].len;
/* This is again balanced, since sum was balanced, and has */
/* allowable depth that differs from i by at most 1. */
forest[i].c = 0;
}
i++;
}
i--;
forest[i].c = sum;
forest[i].len = sum_len;
}
CORD CORD_concat_forest(ForestElement * forest, size_t expected_len)
{
register int i = 0;
CORD sum = 0;
size_t sum_len = 0;
while (sum_len != expected_len) {
if (forest[i].c != 0) {
sum = CORD_cat(forest[i].c, sum);
sum_len += forest[i].len;
}
i++;
}
return(sum);
}
/* Insert the frontier of x into forest. Balanced subtrees are */
/* treated as leaves. This potentially adds one to the depth */
/* of the final tree. */
void CORD_balance_insert(CORD x, size_t len, ForestElement * forest)
{
register int depth;
if (CORD_IS_STRING(x)) {
CORD_add_forest(forest, x, len);
} else if (IS_CONCATENATION(x)
&& ((depth = DEPTH(x)) >= MAX_DEPTH
|| len < min_len[depth])) {
register struct Concatenation * conc
= &(((CordRep *)x) -> concatenation);
size_t left_len = LEFT_LEN(conc);
CORD_balance_insert(conc -> left, left_len, forest);
CORD_balance_insert(conc -> right, len - left_len, forest);
} else /* function or balanced */ {
CORD_add_forest(forest, x, len);
}
}
CORD CORD_balance(CORD x)
{
Forest forest;
register size_t len;
if (x == 0) return(0);
if (CORD_IS_STRING(x)) return(x);
if (!min_len_init) CORD_init_min_len();
len = LEN(x);
CORD_init_forest(forest, len);
CORD_balance_insert(x, len, forest);
return(CORD_concat_forest(forest, len));
}
/* Position primitives */
/* Private routines to deal with the hard cases only: */
/* P contains a prefix of the path to cur_pos. Extend it to a full */
/* path and set up leaf info. */
/* Return 0 if past the end of cord, 1 o.w. */
void CORD__extend_path(register CORD_pos p)
{
register struct CORD_pe * current_pe = &(p[0].path[p[0].path_len]);
register CORD top = current_pe -> pe_cord;
register size_t pos = p[0].cur_pos;
register size_t top_pos = current_pe -> pe_start_pos;
register size_t top_len = GEN_LEN(top);
/* Fill in the rest of the path. */
while(!CORD_IS_STRING(top) && IS_CONCATENATION(top)) {
register struct Concatenation * conc =
&(((CordRep *)top) -> concatenation);
register size_t left_len;
left_len = LEFT_LEN(conc);
current_pe++;
if (pos >= top_pos + left_len) {
current_pe -> pe_cord = top = conc -> right;
current_pe -> pe_start_pos = top_pos = top_pos + left_len;
top_len -= left_len;
} else {
current_pe -> pe_cord = top = conc -> left;
current_pe -> pe_start_pos = top_pos;
top_len = left_len;
}
p[0].path_len++;
}
/* Fill in leaf description for fast access. */
if (CORD_IS_STRING(top)) {
p[0].cur_leaf = top;
p[0].cur_start = top_pos;
p[0].cur_end = top_pos + top_len;
} else {
p[0].cur_end = 0;
}
if (pos >= top_pos + top_len) p[0].path_len = CORD_POS_INVALID;
}
char CORD__pos_fetch(register CORD_pos p)
{
/* Leaf is a function node */
struct CORD_pe * pe = &((p)[0].path[(p)[0].path_len]);
CORD leaf = pe -> pe_cord;
register struct Function * f = &(((CordRep *)leaf) -> function);
if (!IS_FUNCTION(leaf)) ABORT("CORD_pos_fetch: bad leaf");
return ((*(f -> fn))(p[0].cur_pos - pe -> pe_start_pos, f -> client_data));
}
void CORD__next(register CORD_pos p)
{
register size_t cur_pos = p[0].cur_pos + 1;
register struct CORD_pe * current_pe = &((p)[0].path[(p)[0].path_len]);
register CORD leaf = current_pe -> pe_cord;
/* Leaf is not a string or we're at end of leaf */
p[0].cur_pos = cur_pos;
if (!CORD_IS_STRING(leaf)) {
/* Function leaf */
register struct Function * f = &(((CordRep *)leaf) -> function);
register size_t start_pos = current_pe -> pe_start_pos;
register size_t end_pos = start_pos + f -> len;
if (cur_pos < end_pos) {
/* Fill cache and return. */
register size_t i;
register size_t limit = cur_pos + FUNCTION_BUF_SZ;
register CORD_fn fn = f -> fn;
register void * client_data = f -> client_data;
if (limit > end_pos) {
limit = end_pos;
}
for (i = cur_pos; i < limit; i++) {
p[0].function_buf[i - cur_pos] =
(*fn)(i - start_pos, client_data);
}
p[0].cur_start = cur_pos;
p[0].cur_leaf = p[0].function_buf;
p[0].cur_end = limit;
return;
}
}
/* End of leaf */
/* Pop the stack until we find two concatenation nodes with the */
/* same start position: this implies we were in left part. */
{
while (p[0].path_len > 0
&& current_pe[0].pe_start_pos != current_pe[-1].pe_start_pos) {
p[0].path_len--;
current_pe--;
}
if (p[0].path_len == 0) {
p[0].path_len = CORD_POS_INVALID;
return;
}
}
p[0].path_len--;
CORD__extend_path(p);
}
void CORD__prev(register CORD_pos p)
{
register struct CORD_pe * pe = &(p[0].path[p[0].path_len]);
if (p[0].cur_pos == 0) {
p[0].path_len = CORD_POS_INVALID;
return;
}
p[0].cur_pos--;
if (p[0].cur_pos >= pe -> pe_start_pos) return;
/* Beginning of leaf */
/* Pop the stack until we find two concatenation nodes with the */
/* different start position: this implies we were in right part. */
{
register struct CORD_pe * current_pe = &((p)[0].path[(p)[0].path_len]);
while (p[0].path_len > 0
&& current_pe[0].pe_start_pos == current_pe[-1].pe_start_pos) {
p[0].path_len--;
current_pe--;
}
}
p[0].path_len--;
CORD__extend_path(p);
}
#undef CORD_pos_fetch
#undef CORD_next
#undef CORD_prev
#undef CORD_pos_to_index
#undef CORD_pos_to_cord
#undef CORD_pos_valid
char CORD_pos_fetch(register CORD_pos p)
{
if (p[0].cur_start <= p[0].cur_pos && p[0].cur_pos < p[0].cur_end) {
return(p[0].cur_leaf[p[0].cur_pos - p[0].cur_start]);
} else {
return(CORD__pos_fetch(p));
}
}
void CORD_next(CORD_pos p)
{
if (p[0].cur_pos < p[0].cur_end - 1) {
p[0].cur_pos++;
} else {
CORD__next(p);
}
}
void CORD_prev(CORD_pos p)
{
if (p[0].cur_end != 0 && p[0].cur_pos > p[0].cur_start) {
p[0].cur_pos--;
} else {
CORD__prev(p);
}
}
size_t CORD_pos_to_index(CORD_pos p)
{
return(p[0].cur_pos);
}
CORD CORD_pos_to_cord(CORD_pos p)
{
return(p[0].path[0].pe_cord);
}
int CORD_pos_valid(CORD_pos p)
{
return(p[0].path_len != CORD_POS_INVALID);
}
void CORD_set_pos(CORD_pos p, CORD x, size_t i)
{
if (x == CORD_EMPTY) {
p[0].path_len = CORD_POS_INVALID;
return;
}
p[0].path[0].pe_cord = x;
p[0].path[0].pe_start_pos = 0;
p[0].path_len = 0;
p[0].cur_pos = i;
CORD__extend_path(p);
}
Reference in New Issue View Git Blame Copy Permalink