gecko/js/src/jsstrinlines.h

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef jsstrinlines_h___
#define jsstrinlines_h___

#include "mozilla/Attributes.h"

#include "jsatom.h"
#include "jsstr.h"

#include "jscntxtinlines.h"
#include "jsgcinlines.h"
#include "vm/String-inl.h"

namespace js {

class RopeBuilder {
    JSContext *cx;
    RootedString res;

    RopeBuilder(const RopeBuilder &other) MOZ_DELETE;
    void operator=(const RopeBuilder &other) MOZ_DELETE;

  public:
    RopeBuilder(JSContext *cx)
      : cx(cx), res(cx, cx->runtime->emptyString)
    {}

    inline bool append(HandleString str) {
        res = ConcatStrings<CanGC>(cx, res, str);
        return !!res;
    }

    inline JSString *result() {
        return res;
    }
};

class StringSegmentRange
{
    /*
     * If malloc() shows up in any profiles from this vector, we can add a new
     * StackAllocPolicy which stashes a reusable freed-at-gc buffer in the cx.
     */
    AutoStringVector stack;
    Rooted<JSLinearString*> cur;

    bool settle(JSString *str) {
        while (str->isRope()) {
            JSRope &rope = str->asRope();
            if (!stack.append(rope.rightChild()))
                return false;
            str = rope.leftChild();
        }
        cur = &str->asLinear();
        return true;
    }

  public:
    StringSegmentRange(JSContext *cx)
      : stack(cx), cur(cx)
    {}

    JS_WARN_UNUSED_RESULT bool init(JSString *str) {
        JS_ASSERT(stack.empty());
        return settle(str);
    }

    bool empty() const {
        return cur == NULL;
    }

    JSLinearString *front() const {
        JS_ASSERT(!cur->isRope());
        return cur;
    }

    JS_WARN_UNUSED_RESULT bool popFront() {
        JS_ASSERT(!empty());
        if (stack.empty()) {
            cur = NULL;
            return true;
        }
        return settle(stack.popCopy());
    }
};

/*
 * Return s advanced past any Unicode white space characters.
 */
static inline const jschar *
SkipSpace(const jschar *s, const jschar *end)
{
    JS_ASSERT(s <= end);

    while (s < end && unicode::IsSpace(*s))
        s++;

    return s;
}

/*
 * Return less than, equal to, or greater than zero depending on whether
 * s1 is less than, equal to, or greater than s2.
 */
inline bool
CompareChars(const jschar *s1, size_t l1, const jschar *s2, size_t l2, int32_t *result)
{
    size_t n = Min(l1, l2);
    for (size_t i = 0; i < n; i++) {
        if (int32_t cmp = s1[i] - s2[i]) {
            *result = cmp;
            return true;
        }
    }

    *result = (int32_t)(l1 - l2);
    return true;
}

}  /* namespace js */

#endif /* jsstrinlines_h___ */