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Reduce stack usage in loop(). No need to duplicate

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topic string onto stack before giving it to callback()
Just move it one byte in buffer to add space for 'C' string end \0x00
This commit is contained in:
Edwin vd Oetelaar PA2LVD 2016-06-26 20:53:07 +02:00
parent 35ead348e3
commit d724864095
1 changed files with 4 additions and 6 deletions
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10
src/PubSubClient.cpp
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@ -306,12 +306,10 @@ boolean PubSubClient::loop() {
uint8_t type = buffer[0]&0xF0; uint8_t type = buffer[0]&0xF0;
if (type == MQTTPUBLISH) { if (type == MQTTPUBLISH) {
if (callback) { if (callback) {
uint16_t tl = (buffer[llen+1]<<8)+buffer[llen+2]; uint16_t tl = (buffer[llen+1]<<8)+buffer[llen+2]; /* topic length in bytes */
char topic[tl+1]; memmove(buffer+llen+2,buffer+llen+3,tl); /* move topic inside buffer 1 byte to front */
for (uint16_t i=0;i<tl;i++) { buffer[llen+2+tl] = 0; /* end the topic as a 'C' string with \x00 */
topic[i] = buffer[llen+3+i]; char *topic = (char*) buffer+llen+2;
}
topic[tl] = 0;
// msgId only present for QOS>0 // msgId only present for QOS>0
if ((buffer[0]&0x06) == MQTTQOS1) { if ((buffer[0]&0x06) == MQTTQOS1) {
msgId = (buffer[llen+3+tl]<<8)+buffer[llen+3+tl+1]; msgId = (buffer[llen+3+tl]<<8)+buffer[llen+3+tl+1];