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/* helper.h
* Copyright (c) 2011, Peter Ohler
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* - Neither the name of Peter Ohler nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __OX_HELPER_H__
#define __OX_HELPER_H__
#include "type.h"
#define HELPER_STACK_INC 16
typedef struct _Helper {
ID var; /* Object var ID */
VALUE obj; /* object created or Qundef if not appropriate */
Type type; /* type of object in obj */
} *Helper;
typedef struct _HelperStack {
struct _Helper base[HELPER_STACK_INC];
Helper head; /* current stack */
Helper end; /* stack end */
Helper tail; /* pointer to one past last element name on stack */
} *HelperStack;
inline static void
helper_stack_init(HelperStack stack) {
stack->head = stack->base;
stack->end = stack->base + sizeof(stack->base) / sizeof(struct _Helper);
stack->tail = stack->head;
}
inline static int
helper_stack_empty(HelperStack stack) {
return (stack->head == stack->tail);
}
inline static int
helper_stack_depth(HelperStack stack) {
return (int)(stack->tail - stack->head);
}
inline static void
helper_stack_cleanup(HelperStack stack) {
if (stack->base != stack->head) {
xfree(stack->head);
stack->head = stack->base;
}
}
inline static Helper
helper_stack_push(HelperStack stack, ID var, VALUE obj, Type type) {
if (stack->end <= stack->tail) {
size_t len = stack->end - stack->head;
size_t toff = stack->tail - stack->head;
if (stack->base == stack->head) {
stack->head = ALLOC_N(struct _Helper, len + HELPER_STACK_INC);
memcpy(stack->head, stack->base, sizeof(struct _Helper) * len);
} else {
REALLOC_N(stack->head, struct _Helper, len + HELPER_STACK_INC);
}
stack->tail = stack->head + toff;
stack->end = stack->head + len + HELPER_STACK_INC;
}
stack->tail->var = var;
stack->tail->obj = obj;
stack->tail->type = type;
stack->tail++;
return stack->tail - 1;
}
inline static Helper
helper_stack_peek(HelperStack stack) {
if (stack->head < stack->tail) {
return stack->tail - 1;
}
return 0;
}
inline static Helper
helper_stack_pop(HelperStack stack) {
if (stack->head < stack->tail) {
stack->tail--;
return stack->tail;
}
return 0;
}
#endif /* __OX_HELPER_H__ */
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