Optimizations to AssTime::ParseASS()

Originally committed to SVN as r1102.

aegisub/ass_time.cpp

@@ -36,10 +36,11 @@
 
 ////////////
 // Includes
-#include "ass_time.h"
-#include "vfr.h"
 #include <fstream>
 #include <algorithm>
+#include "ass_time.h"
+#include "vfr.h"
+#include "utils.h"
 
 
 
@@ -54,37 +55,26 @@ AssTime::AssTime () {
 // Parses from ASS
 // ---------------
 // Note that this function is atomic, it won't touch the values if it's invalid.
-void AssTime::ParseASS (const wxString _text) {
+void AssTime::ParseASS (const wxString text) {
 	// Prepare
-	wxString text = _text;
-	text.Trim(true);
-	text.Trim(false);
-	wxString temp;
 	size_t pos = 0;
 	size_t end = 0;
-	long th,tm,ts,tms;
+	long th,tm,tms;
-	double ts_raw;
 
 	try {
 		// Hours
 		end = text.Find(_T(':'));
-		temp = text.Left(end);
+		th = StringToInt(text,0,end);
-		if (!temp.ToLong(&th)) throw 0;
-		pos = end+1;
-		text[end] = _T(' ');
 
 		// Minutes
-		end = text.Find(_T(':'));
+		pos = end+1;
-		temp = text.Mid(pos,end-pos);
+		while (text[++end] != _T(':'));
-		if (!temp.ToLong(&tm)) throw 0;
+		tm = StringToInt(text,pos,end);
 
-		// Seconds
+		// Miliseconds (includes seconds)
-		temp = text.Mid(end+1);
+		pos = end+1;
-		if (!temp.ToDouble(&ts_raw)) throw 0;
+		end = text.Length();
-
+		tms = StringToFix(text,3,pos,end);
-		// Split into seconds and fraction
-		ts = (long int)(ts_raw);
-		tms = (long int)((ts_raw-ts)*1000+0.5);
 	}
 
 	// Something went wrong, don't change anything
@@ -93,7 +83,7 @@ void AssTime::ParseASS (const wxString _text) {
 	}
 
 	// OK, set values
-	time = tms + ts*1000 + tm*60000 + th*3600000;
+	time = tms + tm*60000 + th*3600000;
 }
 
 

aegisub/text_file_reader.cpp

@@ -198,9 +198,9 @@ wxString TextFileReader::ReadLineFromFile() {
 	if (Is16) {
 		char charbuffer[3];
 		charbuffer[2] = 0;
-		char aux;
 		wchar_t ch = 0;
 		int n = 0;
+		size_t len = 0;
 #ifdef TEXT_READER_USE_STDIO
 		while (ch != L'\n' && !feof(file)) {
 			// Read two chars from file
@@ -213,19 +213,19 @@ wxString TextFileReader::ReadLineFromFile() {
 
 			// Swap bytes for big endian
 			if (swap) {
-				aux = charbuffer[0];
+				register char aux = charbuffer[0];
 				charbuffer[0] = charbuffer[1];
 				charbuffer[1] = aux;
 			}
 
 			// Convert two chars into a widechar and append to string
 			ch = *((wchar_t*)charbuffer);
-			if (wxbuffer.Length() == bufAlloc) {
+			if (len >= bufAlloc - 1) {
 				bufAlloc *= 2;
 				wxbuffer.Alloc(bufAlloc);
 			}
 			wxbuffer += ch;
-			n++;
+			len++;
 		}
 	}
 

aegisub/utils.cpp

@@ -283,3 +283,75 @@ void GetWordBoundaries(const wxString text,IntPairVector &results,int start,int
 		}
 	}
 }
+
+
+/////////////////////
+// String to integer
+// wxString::ToLong() is slow and not as flexible
+int StringToInt(const wxString &str,size_t start,size_t end) {
+	// Initialize to zero and get length if end set to -1
+	int sign = 1;
+	int value = 0;
+	if (end == -1) end = str.Length();
+
+	for (size_t pos=start;pos<end;pos++) {
+		// Get value and check if it's a number
+		int val = (int)(str[pos]);
+		if (val == _T(' ') || val == _T('\t')) continue;
+		if (val == _T('-')) sign = -1;
+		if (val < _T('0') || val > _T('9')) break;
+
+		// Shift value to next decimal place and increment the value just read
+		value = value * 10 + (val - _T('0'));
+	}
+
+	return value*sign;
+}
+
+
+
+/////////////////////////
+// String to fixed point
+int StringToFix(const wxString &str,size_t decimalPlaces,size_t start,size_t end) {
+	// Parts of the number
+	int sign = 1;
+	int major = 0;
+	int minor = 0;
+	if (end == -1) end = str.Length();
+	bool inMinor = false;
+	int *dst = &major;
+	size_t mCount = 0;
+
+	for (size_t pos=start;pos<end;pos++) {
+		// Get value and check if it's a number
+		int val = (int)(str[pos]);
+		if (val == _T(' ') || val == _T('\t')) continue;
+		if (val == _T('-')) sign = -1;
+
+		// Switch to minor
+		if (val == _T('.') || val == _T(',')) {
+			if (inMinor) break;
+			inMinor = true;
+			dst = &minor;
+			mCount = 0;
+			continue;
+		}
+		if (val < _T('0') || val > _T('9')) break;
+		*dst = (*dst * 10) + (val - _T('0'));
+		mCount++;
+	}
+
+	// Change minor to have the right number of decimal places
+	while (mCount > decimalPlaces) {
+		minor /= 10;
+		mCount--;
+	}
+	while (mCount < decimalPlaces) {
+		minor *= 10;
+		mCount++;
+	}
+
+	// Shift major and return
+	for (size_t i=0;i<decimalPlaces;i++) major *= 10;
+	return (major + minor)*sign;
+}

aegisub/utils.h

@@ -67,6 +67,8 @@ wxString PrettySize(int bytes);
 wxMenuItem *AppendBitmapMenuItem (wxMenu* parentMenu,int id,wxString text,wxString help,wxBitmap bmp,int pos=-1);
 int SmallestPowerOf2(int x);
 void GetWordBoundaries(const wxString text,IntPairVector &results,int start=0,int end=-1);
+int StringToInt(const wxString &str,size_t start=0,size_t end=-1);
+int StringToFix(const wxString &str,size_t decimalPlaces,size_t start=0,size_t end=-1);
 
 
 //////////
@@ -87,7 +89,8 @@ void GetWordBoundaries(const wxString text,IntPairVector &results,int start=0,in
 #ifdef __VISUALC__
 #define FORCEINLINE __forceinline
 #else
-#define FORCEINLINE inline	// __attribute__((always_inline)) gives me errors on g++ ~amz
+#define FORCEINLINE inline
+// __attribute__((always_inline)) gives me errors on g++ ~amz
 #endif
 #endif