diff options
Diffstat (limited to 'src/networking.c')
| -rw-r--r-- | src/networking.c | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/src/networking.c b/src/networking.c index 6bf39d11a..d6471ee7c 100644 --- a/src/networking.c +++ b/src/networking.c @@ -840,13 +840,29 @@ void addReplyDouble(client *c, double d) { d > 0 ? 6 : 7); } } else { - char dbuf[MAX_LONG_DOUBLE_CHARS+3], - sbuf[MAX_LONG_DOUBLE_CHARS+32]; - int dlen, slen; + char dbuf[MAX_LONG_DOUBLE_CHARS+32]; + int dlen = 0; if (c->resp == 2) { - dlen = snprintf(dbuf,sizeof(dbuf),"%.17g",d); - slen = snprintf(sbuf,sizeof(sbuf),"$%d\r\n%s\r\n",dlen,dbuf); - addReplyProto(c,sbuf,slen); + /* In order to prepend the string length before the formatted number, + * but still avoid an extra memcpy of the whole number, we reserve space + * for maximum header `$0000\r\n`, print double, add the resp header in + * front of it, and then send the buffer with the right `start` offset. */ + int dlen = snprintf(dbuf+7,sizeof(dbuf) - 7,"%.17g",d); + int digits = digits10(dlen); + int start = 4 - digits; + dbuf[start] = '$'; + + /* Convert `dlen` to string, putting it's digits after '$' and before the + * formatted double string. */ + for(int i = digits, val = dlen; val && i > 0 ; --i, val /= 10) { + dbuf[start + i] = "0123456789"[val % 10]; + } + + dbuf[5] = '\r'; + dbuf[6] = '\n'; + dbuf[dlen+7] = '\r'; + dbuf[dlen+8] = '\n'; + addReplyProto(c,dbuf+start,dlen+9-start); } else { dlen = snprintf(dbuf,sizeof(dbuf),",%.17g\r\n",d); addReplyProto(c,dbuf,dlen); |