abCalc/abCStack.c

104 lines
1.7 KiB
C

/*
abCStack.c
By: Jeremy Rand
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "abCStack.h"
#include "abCError.h"
abCalcExpr gStack[AB_CALC_STACK_DEPTH];
static int gStackNumItems = 0;
void abCalcStackInit(void)
{
}
abCalcExpr *abCalcStackExprPush(abCalcExpr *expr)
{
abCalcExpr *result = NULL;
if (gStackNumItems >= AB_CALC_STACK_DEPTH) {
abCalcRaiseError(abCalcStackFullError, NULL);
return NULL;
}
if ((gStackNumItems < AB_CALC_STACK_DEPTH) &&
(expr != NULL)) {
result = &(gStack[gStackNumItems]);
memcpy(result, expr, sizeof(*expr));
gStackNumItems++;
}
return result;
}
abCalcExpr *abCalcStackExprPop(abCalcExpr *expr)
{
abCalcExpr *result = NULL;
if (gStackNumItems < 1)
return NULL;
gStackNumItems--;
if (expr != NULL) {
result = expr;
memcpy(expr, &(gStack[gStackNumItems]), sizeof(*expr));
}
return result;
}
int abCalcStackNumItems(void)
{
return gStackNumItems;
}
abCalcExpr *abCalcStackExprAt(int depth)
{
abCalcExpr *result = NULL;
if (depth < gStackNumItems) {
result = &(gStack[gStackNumItems - 1 - depth]);
}
return result;
}
char *abCalcStackExprStringAt(int depth, char *buffer, int addPrefix)
{
static char tmpBuffer[AB_CALC_EXPR_STRING_MAX];
if (buffer == NULL)
return NULL;
if (addPrefix) {
sprintf(buffer, "%3d: ", depth + 1);
} else {
buffer[0] = '\0';
}
if (depth < gStackNumItems) {
if (abCalcFormatExpr(&(gStack[gStackNumItems - 1 - depth]), tmpBuffer) != NULL) {
strcat(buffer, tmpBuffer);
}
}
return buffer;
}
void abCalcStackClear(void)
{
gStackNumItems = 0;
}