Bit-related string operations moved to bitop.c

All the general string operations are implemented in t_string.c, however
the bit operations, while targeting the string type, are better served
in a specific file where we have the implementations of the following
four commands and helper functions:

    GETBIT
    SETBIT
    BITOP
    BITCOUNT

In the future this file will probably contain more code related to
making the BITOP and BITCOUNT operations faster.

src/Makefile

@@ -96,7 +96,7 @@ QUIET_LINK = @printf '    %b %b\n' $(LINKCOLOR)LINK$(ENDCOLOR) $(BINCOLOR)$@$(EN
 endif
 
 REDIS_SERVER_NAME= redis-server
-REDIS_SERVER_OBJ= adlist.o ae.o anet.o dict.o redis.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o crc16.o endianconv.o slowlog.o scripting.o bio.o rio.o rand.o memtest.o crc64.o
+REDIS_SERVER_OBJ= adlist.o ae.o anet.o dict.o redis.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o crc16.o endianconv.o slowlog.o scripting.o bio.o rio.o rand.o memtest.o crc64.o bitop.o
 REDIS_CLI_NAME= redis-cli
 REDIS_CLI_OBJ= anet.o sds.o adlist.o redis-cli.o zmalloc.o release.o anet.o ae.o
 REDIS_BENCHMARK_NAME= redis-benchmark

src/bitop.c

+#include "redis.h"
+
+/* -----------------------------------------------------------------------------
+ * Bits related string commands: GETBIT, SETBIT, BITCOUNT, BITOP.
+ * -------------------------------------------------------------------------- */
+
+#define BITOP_AND   0
+#define BITOP_OR    1
+#define BITOP_XOR   2
+#define BITOP_NOT   3
+
+/* This helper function used by GETBIT / SETBIT parses the bit offset arguemnt
+ * making sure an error is returned if it is negative or if it overflows
+ * Redis 512 MB limit for the string value. */
+static int getBitOffsetFromArgument(redisClient *c, robj *o, size_t *offset) {
+    long long loffset;
+    char *err = "bit offset is not an integer or out of range";
+
+    if (getLongLongFromObjectOrReply(c,o,&loffset,err) != REDIS_OK)
+        return REDIS_ERR;
+
+    /* Limit offset to 512MB in bytes */
+    if ((loffset < 0) || ((unsigned long long)loffset >> 3) >= (512*1024*1024))
+    {
+        addReplyError(c,err);
+        return REDIS_ERR;
+    }
+
+    *offset = (size_t)loffset;
+    return REDIS_OK;
+}
+
+/* SETBIT key offset bitvalue */
+void setbitCommand(redisClient *c) {
+    robj *o;
+    char *err = "bit is not an integer or out of range";
+    size_t bitoffset;
+    int byte, bit;
+    int byteval, bitval;
+    long on;
+
+    if (getBitOffsetFromArgument(c,c->argv[2],&bitoffset) != REDIS_OK)
+        return;
+
+    if (getLongFromObjectOrReply(c,c->argv[3],&on,err) != REDIS_OK)
+        return;
+
+    /* Bits can only be set or cleared... */
+    if (on & ~1) {
+        addReplyError(c,err);
+        return;
+    }
+
+    o = lookupKeyWrite(c->db,c->argv[1]);
+    if (o == NULL) {
+        o = createObject(REDIS_STRING,sdsempty());
+        dbAdd(c->db,c->argv[1],o);
+    } else {
+        if (checkType(c,o,REDIS_STRING)) return;
+
+        /* Create a copy when the object is shared or encoded. */
+        if (o->refcount != 1 || o->encoding != REDIS_ENCODING_RAW) {
+            robj *decoded = getDecodedObject(o);
+            o = createStringObject(decoded->ptr, sdslen(decoded->ptr));
+            decrRefCount(decoded);
+            dbOverwrite(c->db,c->argv[1],o);
+        }
+    }
+
+    /* Grow sds value to the right length if necessary */
+    byte = bitoffset >> 3;
+    o->ptr = sdsgrowzero(o->ptr,byte+1);
+
+    /* Get current values */
+    byteval = ((char*)o->ptr)[byte];
+    bit = 7 - (bitoffset & 0x7);
+    bitval = byteval & (1 << bit);
+
+    /* Update byte with new bit value and return original value */
+    byteval &= ~(1 << bit);
+    byteval |= ((on & 0x1) << bit);
+    ((char*)o->ptr)[byte] = byteval;
+    signalModifiedKey(c->db,c->argv[1]);
+    server.dirty++;
+    addReply(c, bitval ? shared.cone : shared.czero);
+}
+
+/* GETBIT key offset */
+void getbitCommand(redisClient *c) {
+    robj *o;
+    char llbuf[32];
+    size_t bitoffset;
+    size_t byte, bit;
+    size_t bitval = 0;
+
+    if (getBitOffsetFromArgument(c,c->argv[2],&bitoffset) != REDIS_OK)
+        return;
+
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,o,REDIS_STRING)) return;
+
+    byte = bitoffset >> 3;
+    bit = 7 - (bitoffset & 0x7);
+    if (o->encoding != REDIS_ENCODING_RAW) {
+        if (byte < (size_t)ll2string(llbuf,sizeof(llbuf),(long)o->ptr))
+            bitval = llbuf[byte] & (1 << bit);
+    } else {
+        if (byte < sdslen(o->ptr))
+            bitval = ((char*)o->ptr)[byte] & (1 << bit);
+    }
+
+    addReply(c, bitval ? shared.cone : shared.czero);
+}
+
+/* BITOP op_name target_key src_key1 src_key2 src_key3 ... src_keyN */
+void bitopCommand(redisClient *c) {
+    char *opname = c->argv[1]->ptr;
+    robj *o, *targetkey = c->argv[2];
+    long op, j, numkeys;
+    unsigned char **src; /* Array of source strings pointers. */
+    long *len, maxlen = 0; /* Array of length of src strings, and max len. */
+    unsigned char *res = NULL; /* Resulting string. */
+
+    /* Parse the operation name. */
+    if ((opname[0] == 'a' || opname[0] == 'A') && !strcasecmp(opname,"and"))
+        op = BITOP_AND;
+    else if((opname[0] == 'o' || opname[0] == 'O') && !strcasecmp(opname,"or"))
+        op = BITOP_OR;
+    else if((opname[0] == 'x' || opname[0] == 'X') && !strcasecmp(opname,"xor"))
+        op = BITOP_XOR;
+    else if((opname[0] == 'n' || opname[0] == 'N') && !strcasecmp(opname,"not"))
+        op = BITOP_NOT;
+    else {
+        addReply(c,shared.syntaxerr);
+        return;
+    }
+
+    /* Sanity check: NOT accepts only a single key argument. */
+    if (op == BITOP_NOT && c->argc != 4) {
+        addReplyError(c,"BITOP NOT must be called with a single source key.");
+        return;
+    }
+
+    /* Lookup keys, and store pointers to the string objects into an array. */
+    numkeys = c->argc - 3;
+    src = zmalloc(sizeof(unsigned char*) * numkeys);
+    len = zmalloc(sizeof(long) * numkeys);
+    for (j = 0; j < numkeys; j++) {
+        o = lookupKeyRead(c->db,c->argv[j+3]);
+        /* Handle non-existing keys as empty strings. */
+        if (o == NULL) {
+            src[j] = NULL;
+            len[j] = 0;
+            continue;
+        }
+        /* Return an error if one of the keys is not a string. */
+        if (checkType(c,o,REDIS_STRING)) {
+            zfree(src);
+            zfree(len);
+            return;
+        }
+        src[j] = o->ptr;
+        len[j] = sdslen(o->ptr);
+        if (len[j] > maxlen) maxlen = len[j];
+    }
+
+    /* Compute the bit operation, if at least one string is not empty. */
+    if (maxlen) {
+        res = (unsigned char*) sdsnewlen(NULL,maxlen);
+        unsigned char output, byte;
+        long i;
+
+        for (j = 0; j < maxlen; j++) {
+            output = (len[0] <= j) ? 0 : src[0][j];
+            if (op == BITOP_NOT) output = ~output;
+            for (i = 1; i < numkeys; i++) {
+                byte = (len[i] <= j) ? 0 : src[i][j];
+                switch(op) {
+                case BITOP_AND: output &= byte; break;
+                case BITOP_OR:  output |= byte; break;
+                case BITOP_XOR: output ^= byte; break;
+                }
+            }
+            res[j] = output;
+        }
+    }
+    zfree(src);
+    zfree(len);
+
+    /* Store the computed value into the target key */
+    if (maxlen) {
+        o = createObject(REDIS_STRING,res);
+        setKey(c->db,targetkey,o);
+        decrRefCount(o);
+    } else if (dbDelete(c->db,targetkey)) {
+        signalModifiedKey(c->db,targetkey);
+    }
+    server.dirty++;
+    addReplyLongLong(c,maxlen); /* Return the output string length in bytes. */
+}
+
+/* BITCOUNT key [start end] */
+void bitcountCommand(redisClient *c) {
+    static const unsigned char bitsinbyte[256] = {0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,4,5,5,6,5,6,6,7,5,6,6,7,6,7,7,8};
+    robj *o;
+    long start, end;
+    unsigned char *p;
+    char llbuf[32];
+    size_t strlen;
+
+    /* Lookup, check for type, and return 0 for non existing keys. */
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,o,REDIS_STRING)) return;
+
+    /* Set the 'p' pointer to the string, that can be just a stack allocated
+     * array if our string was integer encoded. */
+    if (o->encoding == REDIS_ENCODING_INT) {
+        p = (unsigned char*) llbuf;
+        strlen = ll2string(llbuf,sizeof(llbuf),(long)o->ptr);
+    } else {
+        p = (unsigned char*) o->ptr;
+        strlen = sdslen(o->ptr);
+    }
+
+    /* Parse start/end range if any. */
+    if (c->argc == 4) {
+        if (getLongFromObjectOrReply(c,c->argv[2],&start,NULL) != REDIS_OK)
+            return;
+        if (getLongFromObjectOrReply(c,c->argv[3],&end,NULL) != REDIS_OK)
+            return;
+        /* Convert negative indexes */
+        if (start < 0) start = strlen+start;
+        if (end < 0) end = strlen+end;
+        if (start < 0) start = 0;
+        if (end < 0) end = 0;
+        if ((unsigned)end >= strlen) end = strlen-1;
+    } else if (c->argc == 2) {
+        /* The whole string. */
+        start = 0;
+        end = strlen-1;
+    } else {
+        /* Syntax error. */
+        addReply(c,shared.syntaxerr);
+        return;
+    }
+
+    /* Precondition: end >= 0 && end < strlen, so the only condition where
+     * zero can be returned is: start > end. */
+    if (start > end) {
+        addReply(c,shared.czero);
+    } else {
+        long bits = 0, bytes = end-start+1;
+
+        /* We can finally count bits. */
+        p += start;
+        while(bytes--) bits += bitsinbyte[*p++];
+        addReplyLongLong(c,bits);
+    }
+}

src/t_string.c

@@ -82,104 +82,6 @@ void getsetCommand(redisClient *c) {
     server.dirty++;
 }
 
-static int getBitOffsetFromArgument(redisClient *c, robj *o, size_t *offset) {
-    long long loffset;
-    char *err = "bit offset is not an integer or out of range";
-
-    if (getLongLongFromObjectOrReply(c,o,&loffset,err) != REDIS_OK)
-        return REDIS_ERR;
-
-    /* Limit offset to 512MB in bytes */
-    if ((loffset < 0) || ((unsigned long long)loffset >> 3) >= (512*1024*1024))
-    {
-        addReplyError(c,err);
-        return REDIS_ERR;
-    }
-
-    *offset = (size_t)loffset;
-    return REDIS_OK;
-}
-
-void setbitCommand(redisClient *c) {
-    robj *o;
-    char *err = "bit is not an integer or out of range";
-    size_t bitoffset;
-    int byte, bit;
-    int byteval, bitval;
-    long on;
-
-    if (getBitOffsetFromArgument(c,c->argv[2],&bitoffset) != REDIS_OK)
-        return;
-
-    if (getLongFromObjectOrReply(c,c->argv[3],&on,err) != REDIS_OK)
-        return;
-
-    /* Bits can only be set or cleared... */
-    if (on & ~1) {
-        addReplyError(c,err);
-        return;
-    }
-
-    o = lookupKeyWrite(c->db,c->argv[1]);
-    if (o == NULL) {
-        o = createObject(REDIS_STRING,sdsempty());
-        dbAdd(c->db,c->argv[1],o);
-    } else {
-        if (checkType(c,o,REDIS_STRING)) return;
-
-        /* Create a copy when the object is shared or encoded. */
-        if (o->refcount != 1 || o->encoding != REDIS_ENCODING_RAW) {
-            robj *decoded = getDecodedObject(o);
-            o = createStringObject(decoded->ptr, sdslen(decoded->ptr));
-            decrRefCount(decoded);
-            dbOverwrite(c->db,c->argv[1],o);
-        }
-    }
-
-    /* Grow sds value to the right length if necessary */
-    byte = bitoffset >> 3;
-    o->ptr = sdsgrowzero(o->ptr,byte+1);
-
-    /* Get current values */
-    byteval = ((char*)o->ptr)[byte];
-    bit = 7 - (bitoffset & 0x7);
-    bitval = byteval & (1 << bit);
-
-    /* Update byte with new bit value and return original value */
-    byteval &= ~(1 << bit);
-    byteval |= ((on & 0x1) << bit);
-    ((char*)o->ptr)[byte] = byteval;
-    signalModifiedKey(c->db,c->argv[1]);
-    server.dirty++;
-    addReply(c, bitval ? shared.cone : shared.czero);
-}
-
-void getbitCommand(redisClient *c) {
-    robj *o;
-    char llbuf[32];
-    size_t bitoffset;
-    size_t byte, bit;
-    size_t bitval = 0;
-
-    if (getBitOffsetFromArgument(c,c->argv[2],&bitoffset) != REDIS_OK)
-        return;
-
-    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
-        checkType(c,o,REDIS_STRING)) return;
-
-    byte = bitoffset >> 3;
-    bit = 7 - (bitoffset & 0x7);
-    if (o->encoding != REDIS_ENCODING_RAW) {
-        if (byte < (size_t)ll2string(llbuf,sizeof(llbuf),(long)o->ptr))
-            bitval = llbuf[byte] & (1 << bit);
-    } else {
-        if (byte < sdslen(o->ptr))
-            bitval = ((char*)o->ptr)[byte] & (1 << bit);
-    }
-
-    addReply(c, bitval ? shared.cone : shared.czero);
-}
-
 void setrangeCommand(redisClient *c) {
     robj *o;
     long offset;
@@ -462,153 +364,3 @@ void strlenCommand(redisClient *c) {
         checkType(c,o,REDIS_STRING)) return;
     addReplyLongLong(c,stringObjectLen(o));
 }
-
-#define BITOP_AND   0
-#define BITOP_OR    1
-#define BITOP_XOR   2
-#define BITOP_NOT   3
-/* BITOP op_name target_key src_key1 src_key2 src_key3 ... src_keyN */
-void bitopCommand(redisClient *c) {
-    char *opname = c->argv[1]->ptr;
-    robj *o, *targetkey = c->argv[2];
-    long op, j, numkeys;
-    unsigned char **src; /* Array of source strings pointers. */
-    long *len, maxlen = 0; /* Array of length of src strings, and max len. */
-    unsigned char *res = NULL; /* Resulting string. */
-
-    /* Parse the operation name. */
-    if ((opname[0] == 'a' || opname[0] == 'A') && !strcasecmp(opname,"and"))
-        op = BITOP_AND;
-    else if((opname[0] == 'o' || opname[0] == 'O') && !strcasecmp(opname,"or"))
-        op = BITOP_OR;
-    else if((opname[0] == 'x' || opname[0] == 'X') && !strcasecmp(opname,"xor"))
-        op = BITOP_XOR;
-    else if((opname[0] == 'n' || opname[0] == 'N') && !strcasecmp(opname,"not"))
-        op = BITOP_NOT;
-    else {
-        addReply(c,shared.syntaxerr);
-        return;
-    }
-
-    /* Sanity check: NOT accepts only a single key argument. */
-    if (op == BITOP_NOT && c->argc != 4) {
-        addReplyError(c,"BITOP NOT must be called with a single source key.");
-        return;
-    }
-
-    /* Lookup keys, and store pointers to the string objects into an array. */
-    numkeys = c->argc - 3;
-    src = zmalloc(sizeof(unsigned char*) * numkeys);
-    len = zmalloc(sizeof(long) * numkeys);
-    for (j = 0; j < numkeys; j++) {
-        o = lookupKeyRead(c->db,c->argv[j+3]);
-        /* Handle non-existing keys as empty strings. */
-        if (o == NULL) {
-            src[j] = NULL;
-            len[j] = 0;
-            continue;
-        }
-        /* Return an error if one of the keys is not a string. */
-        if (checkType(c,o,REDIS_STRING)) {
-            zfree(src);
-            zfree(len);
-            return;
-        }
-        src[j] = o->ptr;
-        len[j] = sdslen(o->ptr);
-        if (len[j] > maxlen) maxlen = len[j];
-    }
-
-    /* Compute the bit operation, if at least one string is not empty. */
-    if (maxlen) {
-        res = (unsigned char*) sdsnewlen(NULL,maxlen);
-        unsigned char output, byte;
-        long i;
-
-        for (j = 0; j < maxlen; j++) {
-            output = (len[0] <= j) ? 0 : src[0][j];
-            if (op == BITOP_NOT) output = ~output;
-            for (i = 1; i < numkeys; i++) {
-                byte = (len[i] <= j) ? 0 : src[i][j];
-                switch(op) {
-                case BITOP_AND: output &= byte; break;
-                case BITOP_OR:  output |= byte; break;
-                case BITOP_XOR: output ^= byte; break;
-                }
-            }
-            res[j] = output;
-        }
-    }
-    zfree(src);
-    zfree(len);
-
-    /* Store the computed value into the target key */
-    if (maxlen) {
-        o = createObject(REDIS_STRING,res);
-        setKey(c->db,targetkey,o);
-        decrRefCount(o);
-    } else if (dbDelete(c->db,targetkey)) {
-        signalModifiedKey(c->db,targetkey);
-    }
-    server.dirty++;
-    addReplyLongLong(c,maxlen); /* Return the output string length in bytes. */
-}
-
-/* BITCOUNT key [start end] */
-void bitcountCommand(redisClient *c) {
-    static const unsigned char bitsinbyte[256] = {0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,4,5,5,6,5,6,6,7,5,6,6,7,6,7,7,8};
-    robj *o;
-    long start, end;
-    unsigned char *p;
-    char llbuf[32];
-    size_t strlen;
-
-    /* Lookup, check for type, and return 0 for non existing keys. */
-    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
-        checkType(c,o,REDIS_STRING)) return;
-
-    /* Set the 'p' pointer to the string, that can be just a stack allocated
-     * array if our string was integer encoded. */
-    if (o->encoding == REDIS_ENCODING_INT) {
-        p = (unsigned char*) llbuf;
-        strlen = ll2string(llbuf,sizeof(llbuf),(long)o->ptr);
-    } else {
-        p = (unsigned char*) o->ptr;
-        strlen = sdslen(o->ptr);
-    }
-
-    /* Parse start/end range if any. */
-    if (c->argc == 4) {
-        if (getLongFromObjectOrReply(c,c->argv[2],&start,NULL) != REDIS_OK)
-            return;
-        if (getLongFromObjectOrReply(c,c->argv[3],&end,NULL) != REDIS_OK)
-            return;
-        /* Convert negative indexes */
-        if (start < 0) start = strlen+start;
-        if (end < 0) end = strlen+end;
-        if (start < 0) start = 0;
-        if (end < 0) end = 0;
-        if ((unsigned)end >= strlen) end = strlen-1;
-    } else if (c->argc == 2) {
-        /* The whole string. */
-        start = 0;
-        end = strlen-1;
-    } else {
-        /* Syntax error. */
-        addReply(c,shared.syntaxerr);
-        return;
-    }
-
-    /* Precondition: end >= 0 && end < strlen, so the only condition where
-     * zero can be returned is: start > end. */
-    if (start > end) {
-        addReply(c,shared.czero);
-    } else {
-        long bits = 0, bytes = end-start+1;
-
-        /* We can finally count bits. */
-        p += start;
-        while(bytes--) bits += bitsinbyte[*p++];
-        addReplyLongLong(c,bits);
-    }
-}