abCalc/expr/abCExpReal.c

218 lines
4.0 KiB
C

/*
abCExpReal.c
By: Jeremy Rand
*/
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "expr/abCExpr.h"
static abCalcExpr *abCalcExprRealParse(abCalcExpr *expr, char *buffer);
static char *abCalcExprRealFormat(abCalcExpr *expr, char *buffer);
static abCalcExprCallbacks gRealCallbacks = {
abCalcExprRealParse,
abCalcExprRealFormat
};
void abCalcExprRealInit(void)
{
abCalcRegisterExprType(abCalcExprTypeReal, &gRealCallbacks);
}
abCalcExpr *abCalcExprRealParse(abCalcExpr *expr, char *buffer)
{
int offset;
int expOffset = -1;
int periodOffset = -1;
int len;
int numOffset = -1;
/* First validate */
if (buffer == NULL)
return NULL;
if (expr == NULL)
return NULL;
len = strlen(buffer);
for (offset = 0; offset < len; offset++) {
switch (buffer[offset]) {
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
numOffset = offset;
break;
case '.':
if (periodOffset != -1)
return NULL;
if (expOffset != -1)
return NULL;
periodOffset = offset;
break;
case '-':
if (offset == 0)
break;
/* Fallthrough */
case '+':
if ((expOffset == -1) ||
((expOffset + 1) != offset))
return NULL;
break;
case 'e':
case 'E':
if (expOffset != -1)
return NULL;
expOffset = offset;
numOffset = -1;
break;
default:
return NULL;
}
}
if (numOffset == -1)
return NULL;
expr->type = abCalcExprTypeReal;
expr->u.real = atof(buffer);
return expr;
}
char *abCalcExprRealFormat(abCalcExpr *expr, char *buffer)
{
abCalcRealType exp;
abCalcRealType value;
static char format[16];
int numDecDigits;
int periodPos = -1;
int zerosStart = -1;
int spaceStart = -1;
int expPos = -1;
int len;
int i;
if (expr == NULL)
return NULL;
if (buffer == NULL)
return NULL;
if (expr->type != abCalcExprTypeReal)
return NULL;
value = expr->u.real;
if (value == 0.0) {
exp = 0.0;
} else {
exp = floor(log10(fabs(value)));
}
if (exp >= 0)
exp++;
if ((exp > 12) ||
(exp < -12)) {
strcpy(format, "%-25.11E");
} else if (exp <= -2) {
double shiftedValue = value * 1.0e12;
if (shiftedValue == floor(shiftedValue)) {
strcpy(format, "%-18.12f");
} else {
strcpy(format, "%-25.11E");
}
} else {
int numDecDigits = (int)(12 - exp);
if (numDecDigits > 12) {
numDecDigits = 12;
}
sprintf(format, "%%-28.%df", numDecDigits);
}
sprintf(buffer, format, value);
len = strlen(buffer);
for (i = 0; i < len; i++) {
switch (buffer[i]) {
case '.':
periodPos = i;
break;
case '0':
if (expPos != -1) {
break;
}
if ((periodPos != -1) &&
(zerosStart == -1)) {
if (periodPos == i - 1) {
zerosStart = periodPos;
} else {
zerosStart = i;
}
}
break;
case 'E':
expPos = i;
break;
case ' ':
spaceStart = i;
break;
default:
if (expPos == -1)
zerosStart = -1;
break;
}
if (spaceStart != -1)
break;
}
if (spaceStart != -1) {
buffer[spaceStart] = '\0';
len = spaceStart;
}
if (zerosStart != -1) {
if (expPos != -1) {
memmove(&buffer[zerosStart], &buffer[expPos], len - expPos + 1);
len = expPos - zerosStart;
}
else {
buffer[zerosStart] = '\0';
}
}
return buffer;
}
void abCalcExprRealSet(abCalcExpr *expr, abCalcRealType value)
{
if (expr == NULL)
return;
expr->type = abCalcExprTypeReal;
expr->u.real = value;
}