Avoiding unnecessary calls to getLength() in libsi/si.c, and avoiding the '& 0xff' in CRC32::crc32() of libsi/util.c

4 files changed, 28 insertions, 16 deletions

diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index 7e1a22d0..96d21c65 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -1362,3 +1362,5 @@ Georg Acher <acher@baycom.de>
  for making tChannelID::operator==() inline for better performance
  for introducing cListBase::count for better performance
  for a patch that was used to implement hash tables to speed up cSchedule::GetEvent()
+ for avoiding unnecessary calls to getLength() in libsi/si.c, and avoiding the
+ '& 0xff' in CRC32::crc32() of libsi/util.c
diff --git a/HISTORY b/HISTORY
index 1bca9213..c2ebcaa7 100644
--- a/HISTORY
+++ b/HISTORY
@@ -3570,3 +3570,5 @@ Video Disk Recorder Revision History
   the schedule it is in.
 - Now using hash tables to speed up cSchedule::GetEvent() (partially based on
   a patch from Georg Acher).
+- Avoiding unnecessary calls to getLength() in libsi/si.c, and avoiding the
+  '& 0xff' in CRC32::crc32() of libsi/util.c (thanks to Georg Acher).
diff --git a/libsi/si.c b/libsi/si.c
index ba97c6e9..90d40303 100644
--- a/libsi/si.c
+++ b/libsi/si.c
@@ -6,7 +6,7 @@
  *   the Free Software Foundation; either version 2 of the License, or     *
  *   (at your option) any later version.                                   *
  *                                                                         *
- *   $Id: si.c 1.13 2004/10/16 15:12:57 kls Exp $
+ *   $Id: si.c 1.14 2005/05/28 14:11:16 kls Exp $
  *                                                                         *
  ***************************************************************************/
 
@@ -114,9 +114,10 @@ Descriptor *DescriptorLoop::getNext(Iterator &it) {
 
 Descriptor *DescriptorLoop::getNext(Iterator &it, DescriptorTag tag, bool returnUnimplemetedDescriptor) {
    Descriptor *d=0;
-   if (isValid() && it.i<getLength()) {
+   int len;
+   if (isValid() && it.i<(len=getLength())) {
       const unsigned char *p=data.getData(it.i);
-      const unsigned char *end=p+getLength()-it.i;
+      const unsigned char *end=p+len-it.i;
       while (p < end) {
          if (Descriptor::getDescriptorTag(p) == tag) {
             d=createDescriptor(it.i, returnUnimplemetedDescriptor);
@@ -132,9 +133,10 @@ Descriptor *DescriptorLoop::getNext(Iterator &it, DescriptorTag tag, bool return
 
 Descriptor *DescriptorLoop::getNext(Iterator &it, DescriptorTag *tags, int arrayLength, bool returnUnimplementedDescriptor) {
    Descriptor *d=0;
-   if (isValid() && it.i<getLength()) {
+   int len;
+   if (isValid() && it.i<(len=getLength())) {
       const unsigned char *p=data.getData(it.i);
-      const unsigned char *end=p+getLength()-it.i;
+      const unsigned char *end=p+len-it.i;
       while (p < end) {
          for (int u=0; u<arrayLength;u++)
             if (Descriptor::getDescriptorTag(p) == tags[u]) {
@@ -211,15 +213,17 @@ bool DescriptorGroup::isComplete() {
 }
 
 char *String::getText() {
-   if (getLength() < 0 || getLength() >4095)
+   int len=getLength();
+   if (len < 0 || len > 4095)
       return strdup("text error"); // caller will delete it!
-   char *data=new char(getLength()+1);
-   decodeText(data, getLength()+1);
+   char *data=new char(len+1);
+   decodeText(data, len+1);
    return data;
 }
 
 char *String::getText(char *buffer, int size) {
-   if (getLength() < 0 || getLength() >= size) {
+   int len=getLength();
+   if (len < 0 || len >= size) {
       strncpy(buffer, "text error", size);
       buffer[size-1] = 0;
       return buffer;
@@ -230,7 +234,8 @@ char *String::getText(char *buffer, int size) {
 
 //taken from VDR, Copyright Klaus Schmidinger <kls@cadsoft.de>
 char *String::getText(char *buffer, char *shortVersion, int sizeBuffer, int sizeShortVersion) {
-   if (getLength() < 0 || getLength() >= sizeBuffer) {
+   int len=getLength();
+   if (len < 0 || len >= sizeBuffer) {
       strncpy(buffer, "text error", sizeBuffer);
       buffer[sizeBuffer-1] = 0;
       *shortVersion = 0;
@@ -254,7 +259,8 @@ void String::decodeText(char *buffer, int size) {
    if (*from == 0x10)
       from += 3; // skips code table info
 
-   for (int i = 0; i < getLength(); i++) {
+   int len=getLength();
+   for (int i = 0; i < len; i++) {
       if (*from == 0)
          break;
       if (    ((' ' <= *from) && (*from <= '~'))
@@ -281,9 +287,8 @@ void String::decodeText(char *buffer, char *shortVersion, int sizeBuffer, int si
    if (*from == 0x10)
       from += 3; // skips code table info
 
-   for (int i = 0; i < getLength(); i++) {
-      if (*from == 0)
-         break;
+   int len=getLength();
+   for (int i = 0; i < len; i++) {
       if (    ((' ' <= *from) && (*from <= '~'))
            || (*from == '\n')
            || (0xA0 <= *from)
@@ -299,6 +304,8 @@ void String::decodeText(char *buffer, char *shortVersion, int sizeBuffer, int si
          IsShortName++;
       else if (*from == 0x87)
          IsShortName--;
+      else if (*from == 0)
+         break;
       from++;
       if (to - buffer >= sizeBuffer - 1 || toShort - shortVersion >= sizeShortVersion - 1)
          break;
diff --git a/libsi/util.c b/libsi/util.c
index c6ad234a..34657948 100644
--- a/libsi/util.c
+++ b/libsi/util.c
@@ -6,7 +6,7 @@
  *   the Free Software Foundation; either version 2 of the License, or     *
  *   (at your option) any later version.                                   *
  *                                                                         *
- *   $Id: util.c 1.4 2004/10/16 09:58:41 kls Exp $
+ *   $Id: util.c 1.5 2005/05/28 14:15:29 kls Exp $
  *                                                                         *
  ***************************************************************************/
 
@@ -263,9 +263,10 @@ u_int32_t CRC32::crc_table[256] = {
 u_int32_t CRC32::crc32 (const char *d, int len, u_int32_t crc)
 {
    register int i;
+   const unsigned char *u=(unsigned char*)d; // Saves '& 0xff'
 
    for (i=0; i<len; i++)
-      crc = (crc << 8) ^ crc_table[((crc >> 24) ^ *d++) & 0xff];
+      crc = (crc << 8) ^ crc_table[((crc >> 24) ^ *u++)];
 
    return crc;
 }