1 files changed, 157 insertions, 0 deletions
diff --git a/src/formula.cpp b/src/formula.cpp
new file mode 100644
index 0000000..7cc1804
--- /dev/null
+++ b/src/formula.cpp
@@ -0,0 +1,157 @@
+#include "formula.h"
+subExceptionDef( ParseException );
+Formula::Formula()
+{
+}
+Formula::~Formula()
+{
+}
+double Formula::run( const char *sFormula )
+{
+        sBuf.write( sFormula, strlen( sFormula ) );
+        sBuf.setPos( 0 );
+        nState = 0;
+        for(;;)
+        {
+                tLook = nextToken();
+                if( tLook.nSym == symEOS )
+                        break;
+                state();
+        }
+        printf("\n");
+        return 0.0;
+}
+void Formula::state()
+{
+        switch( nState )
+        {
+                case 0: // initial expr
+                        switch( tLook.nSym )
+                        {
+                                case symNumber:
+                                        push();
+                                        nState = 1;
+                                        break;
+                        }
+                        break;
+                case 1: // binary operator
+                        switch( tLook.nSym )
+                        {
+                                case symAdd:
+                                case symSubtract:
+                                        push();
+                                        nState = 2;
+                                        break;
+                                case symMultiply:
+                                case symDivide:
+                                        push();
+                                        nState = 3;
+                                        break;
+                        }
+                        break;
+                case 2: // add/subtract
+                        break;
+        }
+}
+void Formula::push()
+{
+        printToken( tLook );
+        sToken.push( tLook );
+}
+Formula::Token Formula::nextToken()
+{
+        char cbuf;
+        for(;;)
+        {
+                if( sBuf.isEOS() )
+                        return Token( symEOS );
+                sBuf.read( &cbuf, 1 );
+                switch( cbuf )
+                {
+                        case '+':
+                                return Token( symAdd );
+                        case '-':
+                                return Token( symSubtract );
+                        case '*':
+                                return Token( symMultiply );
+                        case '/':
+                                return Token( symDivide );
+                        case '(':
+                                return Token( symOpenParen );
+                        case ')':
+                                return Token( symCloseParen );
+                        case ' ':
+                        case '\t':
+                        case '\n':
+                        case '\r':
+                                break;
+                        default:
+                                if( cbuf == '.' || (cbuf >= '0' && cbuf <= '9') )
+                                {
+                                        char num[50];
+                                        int nPos = 0;
+                                        bool bDot = false;
+                                        for(;;)
+                                        {
+                                                num[nPos++] = cbuf;
+                                                if( cbuf == '.' )
+                                                {
+                                                        if( bDot == false )
+                                                                bDot = true;
+                                                        else
+                                                                throw ParseException(
+                                                                        "Numbers cannot have more than one "
+                                                                        ". in them."
+                                                                        );
+                                                }
+                                                sBuf.read( &cbuf, 1 );
+                                                if( (cbuf != '.' && (cbuf < '0' || cbuf > '9')) || 
+                                                        sBuf.isEOS() )
+                                                {
+                                                        if( !sBuf.isEOS() )     sBuf.seek( -1 );
+                                                        num[nPos] = '\0';
+                                                        return Token( symNumber, strtod( num, NULL ) );
+                                                }
+                                        }
+                                }
+                                break;
+                }
+        }
+}
+void Formula::printToken( Token &tok )
+{
+        switch( tok.nSym )
+        {
+                case symEOS:            printf("[EOS] ");                               break;
+                case symAdd:            printf("+ ");                                   break;
+                case symSubtract:       printf("- ");                                   break;
+                case symMultiply:       printf("* ");                                   break;
+                case symDivide:         printf("/ ");                                   break;
+                case symOpenParen:      printf("( ");                                   break;
+                case symCloseParen:     printf(") ");                                   break;
+                case symNumber:         printf("%f ", tok.val.num );    break;
+                default:                        printf("??? ");                                 break;
+        }
+}

diff --git a/src/formula.cpp b/src/formula.cpp new file mode 100644 index 0000000..7cc1804 --- /dev/null +++ b/src/formula.cpp
@@ -0,0 +1,157 @@
	1	#include "formula.h"
	2
	3	subExceptionDef( ParseException );
	4
	5	Formula::Formula()
	6	{
	7	}
	8
	9	Formula::~Formula()
	10	{
	11	}
	12
	13	double Formula::run( const char *sFormula )
	14	{
	15	sBuf.write( sFormula, strlen( sFormula ) );
	16	sBuf.setPos( 0 );
	17
	18	nState = 0;
	19	for(;;)
	20	{
	21	tLook = nextToken();
	22	if( tLook.nSym == symEOS )
	23	break;
	24	state();
	25	}
	26	printf("\n");
	27	return 0.0;
	28	}
	29
	30	void Formula::state()
	31	{
	32	switch( nState )
	33	{
	34	case 0: // initial expr
	35	switch( tLook.nSym )
	36	{
	37	case symNumber:
	38	push();
	39	nState = 1;
	40	break;
	41	}
	42	break;
	43
	44	case 1: // binary operator
	45	switch( tLook.nSym )
	46	{
	47	case symAdd:
	48	case symSubtract:
	49	push();
	50	nState = 2;
	51	break;
	52
	53	case symMultiply:
	54	case symDivide:
	55	push();
	56	nState = 3;
	57	break;
	58	}
	59	break;
	60
	61	case 2: // add/subtract
	62	break;
	63	}
	64	}
	65
	66	void Formula::push()
	67	{
	68	printToken( tLook );
	69	sToken.push( tLook );
	70	}
	71
	72	Formula::Token Formula::nextToken()
	73	{
	74	char cbuf;
	75	for(;;)
	76	{
	77	if( sBuf.isEOS() )
	78	return Token( symEOS );
	79
	80	sBuf.read( &cbuf, 1 );
	81	switch( cbuf )
	82	{
	83	case '+':
	84	return Token( symAdd );
	85
	86	case '-':
	87	return Token( symSubtract );
	88
	89	case '*':
	90	return Token( symMultiply );
	91
	92	case '/':
	93	return Token( symDivide );
	94
	95	case '(':
	96	return Token( symOpenParen );
	97
	98	case ')':
	99	return Token( symCloseParen );
	100
	101	case ' ':
	102	case '\t':
	103	case '\n':
	104	case '\r':
	105	break;
	106
	107	default:
	108	if( cbuf == '.' \|\| (cbuf >= '0' && cbuf <= '9') )
	109	{
	110	char num[50];
	111	int nPos = 0;
	112	bool bDot = false;
	113
	114	for(;;)
	115	{
	116	num[nPos++] = cbuf;
	117	if( cbuf == '.' )
	118	{
	119	if( bDot == false )
	120	bDot = true;
	121	else
	122	throw ParseException(
	123	"Numbers cannot have more than one "
	124	". in them."
	125	);
	126	}
	127	sBuf.read( &cbuf, 1 );
	128	if( (cbuf != '.' && (cbuf < '0' \|\| cbuf > '9')) \|\|
	129	sBuf.isEOS() )
	130	{
	131	if( !sBuf.isEOS() ) sBuf.seek( -1 );
	132	num[nPos] = '\0';
	133	return Token( symNumber, strtod( num, NULL ) );
	134	}
	135	}
	136	}
	137	break;
	138	}
	139	}
	140	}
	141
	142	void Formula::printToken( Token &tok )
	143	{
	144	switch( tok.nSym )
	145	{
	146	case symEOS: printf("[EOS] "); break;
	147	case symAdd: printf("+ "); break;
	148	case symSubtract: printf("- "); break;
	149	case symMultiply: printf("* "); break;
	150	case symDivide: printf("/ "); break;
	151	case symOpenParen: printf("( "); break;
	152	case symCloseParen: printf(") "); break;
	153	case symNumber: printf("%f ", tok.val.num ); break;
	154	default: printf("??? "); break;
	155	}
	156	}
	157