From 3f0394b8a91dd77560a2d1ae7bcafced0cbcffcf Mon Sep 17 00:00:00 2001 From: Pieter Noordhuis Date: Sun, 31 Oct 2010 14:42:48 +0100 Subject: Use a fixed size stack instead of a dynamic list for read tasks --- hiredis.c | 111 +++++++++++++++++++++++++++++++++----------------------------- 1 file changed, 59 insertions(+), 52 deletions(-) (limited to 'hiredis.c') diff --git a/hiredis.c b/hiredis.c index 877e446..16fed97 100644 --- a/hiredis.c +++ b/hiredis.c @@ -47,9 +47,8 @@ typedef struct redisReader { sds buf; /* read buffer */ unsigned int pos; /* buffer cursor */ - redisReadTask *rlist; /* list of items to process */ - unsigned int rlen; /* list length */ - unsigned int rpos; /* list cursor */ + redisReadTask rstack[3]; /* stack of read tasks */ + int ridx; /* index of stack */ } redisReader; static redisReply *createReplyObject(int type); @@ -183,8 +182,33 @@ static char *readLine(redisReader *r, int *_len) { return NULL; } +static void moveToNextTask(redisReader *r) { + redisReadTask *cur, *prv; + assert(r->ridx >= 0); + + /* Return a.s.a.p. when the stack is now empty. */ + if (r->ridx == 0) { + r->ridx--; + return; + } + + cur = &(r->rstack[r->ridx]); + prv = &(r->rstack[r->ridx-1]); + assert(prv->type == REDIS_REPLY_ARRAY); + if (cur->idx == prv->elements-1) { + r->ridx--; + moveToNextTask(r); + } else { + /* Reset the type because the next item can be anything */ + assert(cur->idx < prv->elements); + cur->type = -1; + cur->elements = -1; + cur->idx++; + } +} + static int processLineItem(redisReader *r) { - redisReadTask *cur = &(r->rlist[r->rpos]); + redisReadTask *cur = &(r->rstack[r->ridx]); void *obj; char *p; int len; @@ -199,14 +223,14 @@ static int processLineItem(redisReader *r) { /* If there is no root yet, register this object as root. */ if (r->reply == NULL) r->reply = obj; - r->rpos++; + moveToNextTask(r); return 0; } return -1; } static int processBulkItem(redisReader *r) { - redisReadTask *cur = &(r->rlist[r->rpos]); + redisReadTask *cur = &(r->rstack[r->ridx]); void *obj = NULL; char *p, *s; long len; @@ -235,7 +259,7 @@ static int processBulkItem(redisReader *r) { r->pos += bytelen; if (r->reply == NULL) r->reply = obj; - r->rpos++; + moveToNextTask(r); return 0; } } @@ -243,53 +267,42 @@ static int processBulkItem(redisReader *r) { } static int processMultiBulkItem(redisReader *r) { - redisReadTask *cur = &(r->rlist[r->rpos]); + redisReadTask *cur = &(r->rstack[r->ridx]); void *obj; char *p; - long elements, j; + long elements; if ((p = readLine(r,NULL)) != NULL) { elements = strtol(p,NULL,10); if (elements == -1) { obj = r->fn->createNil(cur); + moveToNextTask(r); } else { obj = r->fn->createArray(cur,elements); - /* Modify read list when there are more than 0 elements. */ + /* Modify task stack when there are more than 0 elements. */ if (elements > 0) { - /* Append elements to the read list. */ - r->rlen += elements; - if ((r->rlist = realloc(r->rlist,sizeof(redisReadTask)*r->rlen)) == NULL) - redisOOM(); - - /* Move existing items backwards. */ - memmove(&(r->rlist[r->rpos+1+elements]), - &(r->rlist[r->rpos+1]), - (r->rlen-(r->rpos+1+elements))*sizeof(redisReadTask)); - - /* Populate new read items. */ - redisReadTask *t; - for (j = 0; j < elements; j++) { - t = &(r->rlist[r->rpos+1+j]); - t->type = -1; - t->parent = obj; - t->idx = j; - } + cur->elements = elements; + r->ridx++; + r->rstack[r->ridx].type = -1; + r->rstack[r->ridx].elements = -1; + r->rstack[r->ridx].parent = obj; + r->rstack[r->ridx].idx = 0; + } else { + moveToNextTask(r); } } - if (obj != NULL) { - if (r->reply == NULL) - r->reply = obj; - r->rpos++; - return 0; - } + /* Object was created, so we can always continue. */ + if (r->reply == NULL) + r->reply = obj; + return 0; } return -1; } static int processItem(redisReader *r) { - redisReadTask *cur = &(r->rlist[r->rpos]); + redisReadTask *cur = &(r->rstack[r->ridx]); char *p; sds byte; @@ -347,7 +360,7 @@ void *redisReplyReaderCreate(redisReplyObjectFunctions *fn) { r->error = NULL; r->fn = fn == NULL ? &defaultFunctions : fn; r->buf = sdsempty(); - r->rlist = malloc(sizeof(redisReadTask)*1); + r->ridx = -1; return r; } @@ -368,8 +381,6 @@ void redisReplyReaderFree(void *reader) { r->fn->freeObject(r->reply); if (r->buf != NULL) sdsfree(r->buf); - if (r->rlist != NULL) - free(r->rlist); free(r); } @@ -383,7 +394,7 @@ static void redisSetReplyReaderError(redisReader *r, sds err) { r->buf = sdsempty(); r->pos = 0; } - r->rlen = r->rpos = 0; + r->ridx = -1; r->error = err; } @@ -408,18 +419,17 @@ int redisReplyReaderGetReply(void *reader, void **reply) { if (sdslen(r->buf) == 0) return REDIS_OK; - /* Create first item to process when the item list is empty. */ - if (r->rlen == 0) { - r->rlist = realloc(r->rlist,sizeof(redisReadTask)*1); - r->rlist[0].type = -1; - r->rlist[0].parent = NULL; - r->rlist[0].idx = -1; - r->rlen = 1; - r->rpos = 0; + /* Set first item to process when the stack is empty. */ + if (r->ridx == -1) { + r->rstack[0].type = -1; + r->rstack[0].elements = -1; + r->rstack[0].parent = NULL; + r->rstack[0].idx = -1; + r->ridx = 0; } /* Process items in reply. */ - while (r->rpos < r->rlen) + while (r->ridx >= 0) if (processItem(r) < 0) break; @@ -436,7 +446,7 @@ int redisReplyReaderGetReply(void *reader, void **reply) { } /* Emit a reply when there is one. */ - if (r->rpos == r->rlen) { + if (r->ridx == -1) { void *aux = r->reply; r->reply = NULL; @@ -447,9 +457,6 @@ int redisReplyReaderGetReply(void *reader, void **reply) { r->pos = 0; } - /* Set list of items to read to be empty. */ - r->rlen = r->rpos = 0; - /* Check if there actually *is* a reply. */ if (r->error != NULL) { return REDIS_ERR; -- cgit v1.2.3