Adding upstream version 5:7.2.4.upstream/5%7.2.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1267 insertions, 0 deletions

diff --git a/src/bitops.c b/src/bitops.c
new file mode 100644
index 0000000..23d8055
--- /dev/null
+++ b/src/bitops.c
@@ -0,0 +1,1267 @@
+/* Bit operations.
+ *
+ * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of Redis nor the names of its contributors may be used
+ *     to endorse or promote products derived from this software without
+ *     specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "server.h"
+
+/* -----------------------------------------------------------------------------
+ * Helpers and low level bit functions.
+ * -------------------------------------------------------------------------- */
+
+/* Count number of bits set in the binary array pointed by 's' and long
+ * 'count' bytes. The implementation of this function is required to
+ * work with an input string length up to 512 MB or more (server.proto_max_bulk_len) */
+long long redisPopcount(void *s, long count) {
+    long long bits = 0;
+    unsigned char *p = s;
+    uint32_t *p4;
+    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};
+
+    /* Count initial bytes not aligned to 32 bit. */
+    while((unsigned long)p & 3 && count) {
+        bits += bitsinbyte[*p++];
+        count--;
+    }
+
+    /* Count bits 28 bytes at a time */
+    p4 = (uint32_t*)p;
+    while(count>=28) {
+        uint32_t aux1, aux2, aux3, aux4, aux5, aux6, aux7;
+
+        aux1 = *p4++;
+        aux2 = *p4++;
+        aux3 = *p4++;
+        aux4 = *p4++;
+        aux5 = *p4++;
+        aux6 = *p4++;
+        aux7 = *p4++;
+        count -= 28;
+
+        aux1 = aux1 - ((aux1 >> 1) & 0x55555555);
+        aux1 = (aux1 & 0x33333333) + ((aux1 >> 2) & 0x33333333);
+        aux2 = aux2 - ((aux2 >> 1) & 0x55555555);
+        aux2 = (aux2 & 0x33333333) + ((aux2 >> 2) & 0x33333333);
+        aux3 = aux3 - ((aux3 >> 1) & 0x55555555);
+        aux3 = (aux3 & 0x33333333) + ((aux3 >> 2) & 0x33333333);
+        aux4 = aux4 - ((aux4 >> 1) & 0x55555555);
+        aux4 = (aux4 & 0x33333333) + ((aux4 >> 2) & 0x33333333);
+        aux5 = aux5 - ((aux5 >> 1) & 0x55555555);
+        aux5 = (aux5 & 0x33333333) + ((aux5 >> 2) & 0x33333333);
+        aux6 = aux6 - ((aux6 >> 1) & 0x55555555);
+        aux6 = (aux6 & 0x33333333) + ((aux6 >> 2) & 0x33333333);
+        aux7 = aux7 - ((aux7 >> 1) & 0x55555555);
+        aux7 = (aux7 & 0x33333333) + ((aux7 >> 2) & 0x33333333);
+        bits += ((((aux1 + (aux1 >> 4)) & 0x0F0F0F0F) +
+                    ((aux2 + (aux2 >> 4)) & 0x0F0F0F0F) +
+                    ((aux3 + (aux3 >> 4)) & 0x0F0F0F0F) +
+                    ((aux4 + (aux4 >> 4)) & 0x0F0F0F0F) +
+                    ((aux5 + (aux5 >> 4)) & 0x0F0F0F0F) +
+                    ((aux6 + (aux6 >> 4)) & 0x0F0F0F0F) +
+                    ((aux7 + (aux7 >> 4)) & 0x0F0F0F0F))* 0x01010101) >> 24;
+    }
+    /* Count the remaining bytes. */
+    p = (unsigned char*)p4;
+    while(count--) bits += bitsinbyte[*p++];
+    return bits;
+}
+
+/* Return the position of the first bit set to one (if 'bit' is 1) or
+ * zero (if 'bit' is 0) in the bitmap starting at 's' and long 'count' bytes.
+ *
+ * The function is guaranteed to return a value >= 0 if 'bit' is 0 since if
+ * no zero bit is found, it returns count*8 assuming the string is zero
+ * padded on the right. However if 'bit' is 1 it is possible that there is
+ * not a single set bit in the bitmap. In this special case -1 is returned. */
+long long redisBitpos(void *s, unsigned long count, int bit) {
+    unsigned long *l;
+    unsigned char *c;
+    unsigned long skipval, word = 0, one;
+    long long pos = 0; /* Position of bit, to return to the caller. */
+    unsigned long j;
+    int found;
+
+    /* Process whole words first, seeking for first word that is not
+     * all ones or all zeros respectively if we are looking for zeros
+     * or ones. This is much faster with large strings having contiguous
+     * blocks of 1 or 0 bits compared to the vanilla bit per bit processing.
+     *
+     * Note that if we start from an address that is not aligned
+     * to sizeof(unsigned long) we consume it byte by byte until it is
+     * aligned. */
+
+    /* Skip initial bits not aligned to sizeof(unsigned long) byte by byte. */
+    skipval = bit ? 0 : UCHAR_MAX;
+    c = (unsigned char*) s;
+    found = 0;
+    while((unsigned long)c & (sizeof(*l)-1) && count) {
+        if (*c != skipval) {
+            found = 1;
+            break;
+        }
+        c++;
+        count--;
+        pos += 8;
+    }
+
+    /* Skip bits with full word step. */
+    l = (unsigned long*) c;
+    if (!found) {
+        skipval = bit ? 0 : ULONG_MAX;
+        while (count >= sizeof(*l)) {
+            if (*l != skipval) break;
+            l++;
+            count -= sizeof(*l);
+            pos += sizeof(*l)*8;
+        }
+    }
+
+    /* Load bytes into "word" considering the first byte as the most significant
+     * (we basically consider it as written in big endian, since we consider the
+     * string as a set of bits from left to right, with the first bit at position
+     * zero.
+     *
+     * Note that the loading is designed to work even when the bytes left
+     * (count) are less than a full word. We pad it with zero on the right. */
+    c = (unsigned char*)l;
+    for (j = 0; j < sizeof(*l); j++) {
+        word <<= 8;
+        if (count) {
+            word |= *c;
+            c++;
+            count--;
+        }
+    }
+
+    /* Special case:
+     * If bits in the string are all zero and we are looking for one,
+     * return -1 to signal that there is not a single "1" in the whole
+     * string. This can't happen when we are looking for "0" as we assume
+     * that the right of the string is zero padded. */
+    if (bit == 1 && word == 0) return -1;
+
+    /* Last word left, scan bit by bit. The first thing we need is to
+     * have a single "1" set in the most significant position in an
+     * unsigned long. We don't know the size of the long so we use a
+     * simple trick. */
+    one = ULONG_MAX; /* All bits set to 1.*/
+    one >>= 1;       /* All bits set to 1 but the MSB. */
+    one = ~one;      /* All bits set to 0 but the MSB. */
+
+    while(one) {
+        if (((one & word) != 0) == bit) return pos;
+        pos++;
+        one >>= 1;
+    }
+
+    /* If we reached this point, there is a bug in the algorithm, since
+     * the case of no match is handled as a special case before. */
+    serverPanic("End of redisBitpos() reached.");
+    return 0; /* Just to avoid warnings. */
+}
+
+/* The following set.*Bitfield and get.*Bitfield functions implement setting
+ * and getting arbitrary size (up to 64 bits) signed and unsigned integers
+ * at arbitrary positions into a bitmap.
+ *
+ * The representation considers the bitmap as having the bit number 0 to be
+ * the most significant bit of the first byte, and so forth, so for example
+ * setting a 5 bits unsigned integer to value 23 at offset 7 into a bitmap
+ * previously set to all zeroes, will produce the following representation:
+ *
+ * +--------+--------+
+ * |00000001|01110000|
+ * +--------+--------+
+ *
+ * When offsets and integer sizes are aligned to bytes boundaries, this is the
+ * same as big endian, however when such alignment does not exist, its important
+ * to also understand how the bits inside a byte are ordered.
+ *
+ * Note that this format follows the same convention as SETBIT and related
+ * commands.
+ */
+
+void setUnsignedBitfield(unsigned char *p, uint64_t offset, uint64_t bits, uint64_t value) {
+    uint64_t byte, bit, byteval, bitval, j;
+
+    for (j = 0; j < bits; j++) {
+        bitval = (value & ((uint64_t)1<<(bits-1-j))) != 0;
+        byte = offset >> 3;
+        bit = 7 - (offset & 0x7);
+        byteval = p[byte];
+        byteval &= ~(1 << bit);
+        byteval |= bitval << bit;
+        p[byte] = byteval & 0xff;
+        offset++;
+    }
+}
+
+void setSignedBitfield(unsigned char *p, uint64_t offset, uint64_t bits, int64_t value) {
+    uint64_t uv = value; /* Casting will add UINT64_MAX + 1 if v is negative. */
+    setUnsignedBitfield(p,offset,bits,uv);
+}
+
+uint64_t getUnsignedBitfield(unsigned char *p, uint64_t offset, uint64_t bits) {
+    uint64_t byte, bit, byteval, bitval, j, value = 0;
+
+    for (j = 0; j < bits; j++) {
+        byte = offset >> 3;
+        bit = 7 - (offset & 0x7);
+        byteval = p[byte];
+        bitval = (byteval >> bit) & 1;
+        value = (value<<1) | bitval;
+        offset++;
+    }
+    return value;
+}
+
+int64_t getSignedBitfield(unsigned char *p, uint64_t offset, uint64_t bits) {
+    int64_t value;
+    union {uint64_t u; int64_t i;} conv;
+
+    /* Converting from unsigned to signed is undefined when the value does
+     * not fit, however here we assume two's complement and the original value
+     * was obtained from signed -> unsigned conversion, so we'll find the
+     * most significant bit set if the original value was negative.
+     *
+     * Note that two's complement is mandatory for exact-width types
+     * according to the C99 standard. */
+    conv.u = getUnsignedBitfield(p,offset,bits);
+    value = conv.i;
+
+    /* If the top significant bit is 1, propagate it to all the
+     * higher bits for two's complement representation of signed
+     * integers. */
+    if (bits < 64 && (value & ((uint64_t)1 << (bits-1))))
+        value |= ((uint64_t)-1) << bits;
+    return value;
+}
+
+/* The following two functions detect overflow of a value in the context
+ * of storing it as an unsigned or signed integer with the specified
+ * number of bits. The functions both take the value and a possible increment.
+ * If no overflow could happen and the value+increment fit inside the limits,
+ * then zero is returned, otherwise in case of overflow, 1 is returned,
+ * otherwise in case of underflow, -1 is returned.
+ *
+ * When non-zero is returned (overflow or underflow), if not NULL, *limit is
+ * set to the value the operation should result when an overflow happens,
+ * depending on the specified overflow semantics:
+ *
+ * For BFOVERFLOW_SAT if 1 is returned, *limit it is set maximum value that
+ * you can store in that integer. when -1 is returned, *limit is set to the
+ * minimum value that an integer of that size can represent.
+ *
+ * For BFOVERFLOW_WRAP *limit is set by performing the operation in order to
+ * "wrap" around towards zero for unsigned integers, or towards the most
+ * negative number that is possible to represent for signed integers. */
+
+#define BFOVERFLOW_WRAP 0
+#define BFOVERFLOW_SAT 1
+#define BFOVERFLOW_FAIL 2 /* Used by the BITFIELD command implementation. */
+
+int checkUnsignedBitfieldOverflow(uint64_t value, int64_t incr, uint64_t bits, int owtype, uint64_t *limit) {
+    uint64_t max = (bits == 64) ? UINT64_MAX : (((uint64_t)1<<bits)-1);
+    int64_t maxincr = max-value;
+    int64_t minincr = -value;
+
+    if (value > max || (incr > 0 && incr > maxincr)) {
+        if (limit) {
+            if (owtype == BFOVERFLOW_WRAP) {
+                goto handle_wrap;
+            } else if (owtype == BFOVERFLOW_SAT) {
+                *limit = max;
+            }
+        }
+        return 1;
+    } else if (incr < 0 && incr < minincr) {
+        if (limit) {
+            if (owtype == BFOVERFLOW_WRAP) {
+                goto handle_wrap;
+            } else if (owtype == BFOVERFLOW_SAT) {
+                *limit = 0;
+            }
+        }
+        return -1;
+    }
+    return 0;
+
+handle_wrap:
+    {
+        uint64_t mask = ((uint64_t)-1) << bits;
+        uint64_t res = value+incr;
+
+        res &= ~mask;
+        *limit = res;
+    }
+    return 1;
+}
+
+int checkSignedBitfieldOverflow(int64_t value, int64_t incr, uint64_t bits, int owtype, int64_t *limit) {
+    int64_t max = (bits == 64) ? INT64_MAX : (((int64_t)1<<(bits-1))-1);
+    int64_t min = (-max)-1;
+
+    /* Note that maxincr and minincr could overflow, but we use the values
+     * only after checking 'value' range, so when we use it no overflow
+     * happens. 'uint64_t' cast is there just to prevent undefined behavior on
+     * overflow */
+    int64_t maxincr = (uint64_t)max-value;
+    int64_t minincr = min-value;
+
+    if (value > max || (bits != 64 && incr > maxincr) || (value >= 0 && incr > 0 && incr > maxincr))
+    {
+        if (limit) {
+            if (owtype == BFOVERFLOW_WRAP) {
+                goto handle_wrap;
+            } else if (owtype == BFOVERFLOW_SAT) {
+                *limit = max;
+            }
+        }
+        return 1;
+    } else if (value < min || (bits != 64 && incr < minincr) || (value < 0 && incr < 0 && incr < minincr)) {
+        if (limit) {
+            if (owtype == BFOVERFLOW_WRAP) {
+                goto handle_wrap;
+            } else if (owtype == BFOVERFLOW_SAT) {
+                *limit = min;
+            }
+        }
+        return -1;
+    }
+    return 0;
+
+handle_wrap:
+    {
+        uint64_t msb = (uint64_t)1 << (bits-1);
+        uint64_t a = value, b = incr, c;
+        c = a+b; /* Perform addition as unsigned so that's defined. */
+
+        /* If the sign bit is set, propagate to all the higher order
+         * bits, to cap the negative value. If it's clear, mask to
+         * the positive integer limit. */
+        if (bits < 64) {
+            uint64_t mask = ((uint64_t)-1) << bits;
+            if (c & msb) {
+                c |= mask;
+            } else {
+                c &= ~mask;
+            }
+        }
+        *limit = c;
+    }
+    return 1;
+}
+
+/* Debugging function. Just show bits in the specified bitmap. Not used
+ * but here for not having to rewrite it when debugging is needed. */
+void printBits(unsigned char *p, unsigned long count) {
+    unsigned long j, i, byte;
+
+    for (j = 0; j < count; j++) {
+        byte = p[j];
+        for (i = 0x80; i > 0; i /= 2)
+            printf("%c", (byte & i) ? '1' : '0');
+        printf("|");
+    }
+    printf("\n");
+}
+
+/* -----------------------------------------------------------------------------
+ * Bits related string commands: GETBIT, SETBIT, BITCOUNT, BITOP.
+ * -------------------------------------------------------------------------- */
+
+#define BITOP_AND   0
+#define BITOP_OR    1
+#define BITOP_XOR   2
+#define BITOP_NOT   3
+
+#define BITFIELDOP_GET 0
+#define BITFIELDOP_SET 1
+#define BITFIELDOP_INCRBY 2
+
+/* This helper function used by GETBIT / SETBIT parses the bit offset argument
+ * making sure an error is returned if it is negative or if it overflows
+ * Redis 512 MB limit for the string value or more (server.proto_max_bulk_len).
+ *
+ * If the 'hash' argument is true, and 'bits is positive, then the command
+ * will also parse bit offsets prefixed by "#". In such a case the offset
+ * is multiplied by 'bits'. This is useful for the BITFIELD command. */
+int getBitOffsetFromArgument(client *c, robj *o, uint64_t *offset, int hash, int bits) {
+    long long loffset;
+    char *err = "bit offset is not an integer or out of range";
+    char *p = o->ptr;
+    size_t plen = sdslen(p);
+    int usehash = 0;
+
+    /* Handle #<offset> form. */
+    if (p[0] == '#' && hash && bits > 0) usehash = 1;
+
+    if (string2ll(p+usehash,plen-usehash,&loffset) == 0) {
+        addReplyError(c,err);
+        return C_ERR;
+    }
+
+    /* Adjust the offset by 'bits' for #<offset> form. */
+    if (usehash) loffset *= bits;
+
+    /* Limit offset to server.proto_max_bulk_len (512MB in bytes by default) */
+    if (loffset < 0 || (!mustObeyClient(c) && (loffset >> 3) >= server.proto_max_bulk_len))
+    {
+        addReplyError(c,err);
+        return C_ERR;
+    }
+
+    *offset = loffset;
+    return C_OK;
+}
+
+/* This helper function for BITFIELD parses a bitfield type in the form
+ * <sign><bits> where sign is 'u' or 'i' for unsigned and signed, and
+ * the bits is a value between 1 and 64. However 64 bits unsigned integers
+ * are reported as an error because of current limitations of Redis protocol
+ * to return unsigned integer values greater than INT64_MAX.
+ *
+ * On error C_ERR is returned and an error is sent to the client. */
+int getBitfieldTypeFromArgument(client *c, robj *o, int *sign, int *bits) {
+    char *p = o->ptr;
+    char *err = "Invalid bitfield type. Use something like i16 u8. Note that u64 is not supported but i64 is.";
+    long long llbits;
+
+    if (p[0] == 'i') {
+        *sign = 1;
+    } else if (p[0] == 'u') {
+        *sign = 0;
+    } else {
+        addReplyError(c,err);
+        return C_ERR;
+    }
+
+    if ((string2ll(p+1,strlen(p+1),&llbits)) == 0 ||
+        llbits < 1 ||
+        (*sign == 1 && llbits > 64) ||
+        (*sign == 0 && llbits > 63))
+    {
+        addReplyError(c,err);
+        return C_ERR;
+    }
+    *bits = llbits;
+    return C_OK;
+}
+
+/* This is a helper function for commands implementations that need to write
+ * bits to a string object. The command creates or pad with zeroes the string
+ * so that the 'maxbit' bit can be addressed. The object is finally
+ * returned. Otherwise if the key holds a wrong type NULL is returned and
+ * an error is sent to the client. */
+robj *lookupStringForBitCommand(client *c, uint64_t maxbit, int *dirty) {
+    size_t byte = maxbit >> 3;
+    robj *o = lookupKeyWrite(c->db,c->argv[1]);
+    if (checkType(c,o,OBJ_STRING)) return NULL;
+    if (dirty) *dirty = 0;
+
+    if (o == NULL) {
+        o = createObject(OBJ_STRING,sdsnewlen(NULL, byte+1));
+        dbAdd(c->db,c->argv[1],o);
+        if (dirty) *dirty = 1;
+    } else {
+        o = dbUnshareStringValue(c->db,c->argv[1],o);
+        size_t oldlen = sdslen(o->ptr);
+        o->ptr = sdsgrowzero(o->ptr,byte+1);
+        if (dirty && oldlen != sdslen(o->ptr)) *dirty = 1;
+    }
+    return o;
+}
+
+/* Return a pointer to the string object content, and stores its length
+ * in 'len'. The user is required to pass (likely stack allocated) buffer
+ * 'llbuf' of at least LONG_STR_SIZE bytes. Such a buffer is used in the case
+ * the object is integer encoded in order to provide the representation
+ * without using heap allocation.
+ *
+ * The function returns the pointer to the object array of bytes representing
+ * the string it contains, that may be a pointer to 'llbuf' or to the
+ * internal object representation. As a side effect 'len' is filled with
+ * the length of such buffer.
+ *
+ * If the source object is NULL the function is guaranteed to return NULL
+ * and set 'len' to 0. */
+unsigned char *getObjectReadOnlyString(robj *o, long *len, char *llbuf) {
+    serverAssert(!o || o->type == OBJ_STRING);
+    unsigned char *p = NULL;
+
+    /* Set the 'p' pointer to the string, that can be just a stack allocated
+     * array if our string was integer encoded. */
+    if (o && o->encoding == OBJ_ENCODING_INT) {
+        p = (unsigned char*) llbuf;
+        if (len) *len = ll2string(llbuf,LONG_STR_SIZE,(long)o->ptr);
+    } else if (o) {
+        p = (unsigned char*) o->ptr;
+        if (len) *len = sdslen(o->ptr);
+    } else {
+        if (len) *len = 0;
+    }
+    return p;
+}
+
+/* SETBIT key offset bitvalue */
+void setbitCommand(client *c) {
+    robj *o;
+    char *err = "bit is not an integer or out of range";
+    uint64_t bitoffset;
+    ssize_t byte, bit;
+    int byteval, bitval;
+    long on;
+
+    if (getBitOffsetFromArgument(c,c->argv[2],&bitoffset,0,0) != C_OK)
+        return;
+
+    if (getLongFromObjectOrReply(c,c->argv[3],&on,err) != C_OK)
+        return;
+
+    /* Bits can only be set or cleared... */
+    if (on & ~1) {
+        addReplyError(c,err);
+        return;
+    }
+
+    int dirty;
+    if ((o = lookupStringForBitCommand(c,bitoffset,&dirty)) == NULL) return;
+
+    /* Get current values */
+    byte = bitoffset >> 3;
+    byteval = ((uint8_t*)o->ptr)[byte];
+    bit = 7 - (bitoffset & 0x7);
+    bitval = byteval & (1 << bit);
+
+    /* Either it is newly created, changed length, or the bit changes before and after.
+     * Note that the bitval here is actually a decimal number.
+     * So we need to use `!!` to convert it to 0 or 1 for comparison. */
+    if (dirty || (!!bitval != on)) {
+        /* Update byte with new bit value. */
+        byteval &= ~(1 << bit);
+        byteval |= ((on & 0x1) << bit);
+        ((uint8_t*)o->ptr)[byte] = byteval;
+        signalModifiedKey(c,c->db,c->argv[1]);
+        notifyKeyspaceEvent(NOTIFY_STRING,"setbit",c->argv[1],c->db->id);
+        server.dirty++;
+    }
+
+    /* Return original value. */
+    addReply(c, bitval ? shared.cone : shared.czero);
+}
+
+/* GETBIT key offset */
+void getbitCommand(client *c) {
+    robj *o;
+    char llbuf[32];
+    uint64_t bitoffset;
+    size_t byte, bit;
+    size_t bitval = 0;
+
+    if (getBitOffsetFromArgument(c,c->argv[2],&bitoffset,0,0) != C_OK)
+        return;
+
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,o,OBJ_STRING)) return;
+
+    byte = bitoffset >> 3;
+    bit = 7 - (bitoffset & 0x7);
+    if (sdsEncodedObject(o)) {
+        if (byte < sdslen(o->ptr))
+            bitval = ((uint8_t*)o->ptr)[byte] & (1 << bit);
+    } else {
+        if (byte < (size_t)ll2string(llbuf,sizeof(llbuf),(long)o->ptr))
+            bitval = llbuf[byte] & (1 << bit);
+    }
+
+    addReply(c, bitval ? shared.cone : shared.czero);
+}
+
+/* BITOP op_name target_key src_key1 src_key2 src_key3 ... src_keyN */
+REDIS_NO_SANITIZE("alignment")
+void bitopCommand(client *c) {
+    char *opname = c->argv[1]->ptr;
+    robj *o, *targetkey = c->argv[2];
+    unsigned long op, j, numkeys;
+    robj **objects;      /* Array of source objects. */
+    unsigned char **src; /* Array of source strings pointers. */
+    unsigned long *len, maxlen = 0; /* Array of length of src strings,
+                                       and max len. */
+    unsigned long minlen = 0;    /* Min len among the input keys. */
+    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 {
+        addReplyErrorObject(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);
+    objects = zmalloc(sizeof(robj*) * 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) {
+            objects[j] = NULL;
+            src[j] = NULL;
+            len[j] = 0;
+            minlen = 0;
+            continue;
+        }
+        /* Return an error if one of the keys is not a string. */
+        if (checkType(c,o,OBJ_STRING)) {
+            unsigned long i;
+            for (i = 0; i < j; i++) {
+                if (objects[i])
+                    decrRefCount(objects[i]);
+            }
+            zfree(src);
+            zfree(len);
+            zfree(objects);
+            return;
+        }
+        objects[j] = getDecodedObject(o);
+        src[j] = objects[j]->ptr;
+        len[j] = sdslen(objects[j]->ptr);
+        if (len[j] > maxlen) maxlen = len[j];
+        if (j == 0 || len[j] < minlen) minlen = 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;
+        unsigned long i;
+
+        /* Fast path: as far as we have data for all the input bitmaps we
+         * can take a fast path that performs much better than the
+         * vanilla algorithm. On ARM we skip the fast path since it will
+         * result in GCC compiling the code using multiple-words load/store
+         * operations that are not supported even in ARM >= v6. */
+        j = 0;
+        #ifndef USE_ALIGNED_ACCESS
+        if (minlen >= sizeof(unsigned long)*4 && numkeys <= 16) {
+            unsigned long *lp[16];
+            unsigned long *lres = (unsigned long*) res;
+
+            memcpy(lp,src,sizeof(unsigned long*)*numkeys);
+            memcpy(res,src[0],minlen);
+
+            /* Different branches per different operations for speed (sorry). */
+            if (op == BITOP_AND) {
+                while(minlen >= sizeof(unsigned long)*4) {
+                    for (i = 1; i < numkeys; i++) {
+                        lres[0] &= lp[i][0];
+                        lres[1] &= lp[i][1];
+                        lres[2] &= lp[i][2];
+                        lres[3] &= lp[i][3];
+                        lp[i]+=4;
+                    }
+                    lres+=4;
+                    j += sizeof(unsigned long)*4;
+                    minlen -= sizeof(unsigned long)*4;
+                }
+            } else if (op == BITOP_OR) {
+                while(minlen >= sizeof(unsigned long)*4) {
+                    for (i = 1; i < numkeys; i++) {
+                        lres[0] |= lp[i][0];
+                        lres[1] |= lp[i][1];
+                        lres[2] |= lp[i][2];
+                        lres[3] |= lp[i][3];
+                        lp[i]+=4;
+                    }
+                    lres+=4;
+                    j += sizeof(unsigned long)*4;
+                    minlen -= sizeof(unsigned long)*4;
+                }
+            } else if (op == BITOP_XOR) {
+                while(minlen >= sizeof(unsigned long)*4) {
+                    for (i = 1; i < numkeys; i++) {
+                        lres[0] ^= lp[i][0];
+                        lres[1] ^= lp[i][1];
+                        lres[2] ^= lp[i][2];
+                        lres[3] ^= lp[i][3];
+                        lp[i]+=4;
+                    }
+                    lres+=4;
+                    j += sizeof(unsigned long)*4;
+                    minlen -= sizeof(unsigned long)*4;
+                }
+            } else if (op == BITOP_NOT) {
+                while(minlen >= sizeof(unsigned long)*4) {
+                    lres[0] = ~lres[0];
+                    lres[1] = ~lres[1];
+                    lres[2] = ~lres[2];
+                    lres[3] = ~lres[3];
+                    lres+=4;
+                    j += sizeof(unsigned long)*4;
+                    minlen -= sizeof(unsigned long)*4;
+                }
+            }
+        }
+        #endif
+
+        /* j is set to the next byte to process by the previous loop. */
+        for (; j < maxlen; j++) {
+            output = (len[0] <= j) ? 0 : src[0][j];
+            if (op == BITOP_NOT) output = ~output;
+            for (i = 1; i < numkeys; i++) {
+                int skip = 0;
+                byte = (len[i] <= j) ? 0 : src[i][j];
+                switch(op) {
+                case BITOP_AND:
+                    output &= byte;
+                    skip = (output == 0);
+                    break;
+                case BITOP_OR:
+                    output |= byte;
+                    skip = (output == 0xff);
+                    break;
+                case BITOP_XOR: output ^= byte; break;
+                }
+
+                if (skip) {
+                    break;
+                }
+            }
+            res[j] = output;
+        }
+    }
+    for (j = 0; j < numkeys; j++) {
+        if (objects[j])
+            decrRefCount(objects[j]);
+    }
+    zfree(src);
+    zfree(len);
+    zfree(objects);
+
+    /* Store the computed value into the target key */
+    if (maxlen) {
+        o = createObject(OBJ_STRING,res);
+        setKey(c,c->db,targetkey,o,0);
+        notifyKeyspaceEvent(NOTIFY_STRING,"set",targetkey,c->db->id);
+        decrRefCount(o);
+        server.dirty++;
+    } else if (dbDelete(c->db,targetkey)) {
+        signalModifiedKey(c,c->db,targetkey);
+        notifyKeyspaceEvent(NOTIFY_GENERIC,"del",targetkey,c->db->id);
+        server.dirty++;
+    }
+    addReplyLongLong(c,maxlen); /* Return the output string length in bytes. */
+}
+
+/* BITCOUNT key [start end [BIT|BYTE]] */
+void bitcountCommand(client *c) {
+    robj *o;
+    long long start, end;
+    long strlen;
+    unsigned char *p;
+    char llbuf[LONG_STR_SIZE];
+    int isbit = 0;
+    unsigned char first_byte_neg_mask = 0, last_byte_neg_mask = 0;
+
+    /* Lookup, check for type, and return 0 for non existing keys. */
+    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
+        checkType(c,o,OBJ_STRING)) return;
+    p = getObjectReadOnlyString(o,&strlen,llbuf);
+
+    /* Parse start/end range if any. */
+    if (c->argc == 4 || c->argc == 5) {
+        long long totlen = strlen;
+        /* Make sure we will not overflow */
+        serverAssert(totlen <= LLONG_MAX >> 3);
+        if (getLongLongFromObjectOrReply(c,c->argv[2],&start,NULL) != C_OK)
+            return;
+        if (getLongLongFromObjectOrReply(c,c->argv[3],&end,NULL) != C_OK)
+            return;
+        /* Convert negative indexes */
+        if (start < 0 && end < 0 && start > end) {
+            addReply(c,shared.czero);
+            return;
+        }
+        if (c->argc == 5) {
+            if (!strcasecmp(c->argv[4]->ptr,"bit")) isbit = 1;
+            else if (!strcasecmp(c->argv[4]->ptr,"byte")) isbit = 0;
+            else {
+                addReplyErrorObject(c,shared.syntaxerr);
+                return;
+            }
+        }
+        if (isbit) totlen <<= 3;
+        if (start < 0) start = totlen+start;
+        if (end < 0) end = totlen+end;
+        if (start < 0) start = 0;
+        if (end < 0) end = 0;
+        if (end >= totlen) end = totlen-1;
+        if (isbit && start <= end) {
+            /* Before converting bit offset to byte offset, create negative masks
+             * for the edges. */
+            first_byte_neg_mask = ~((1<<(8-(start&7)))-1) & 0xFF;
+            last_byte_neg_mask = (1<<(7-(end&7)))-1;
+            start >>= 3;
+            end >>= 3;
+        }
+    } else if (c->argc == 2) {
+        /* The whole string. */
+        start = 0;
+        end = strlen-1;
+    } else {
+        /* Syntax error. */
+        addReplyErrorObject(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 bytes = (long)(end-start+1);
+        long long count = redisPopcount(p+start,bytes);
+        if (first_byte_neg_mask != 0 || last_byte_neg_mask != 0) {
+            unsigned char firstlast[2] = {0, 0};
+            /* We may count bits of first byte and last byte which are out of
+            * range. So we need to subtract them. Here we use a trick. We set
+            * bits in the range to zero. So these bit will not be excluded. */
+            if (first_byte_neg_mask != 0) firstlast[0] = p[start] & first_byte_neg_mask;
+            if (last_byte_neg_mask != 0) firstlast[1] = p[end] & last_byte_neg_mask;
+            count -= redisPopcount(firstlast,2);
+        }
+        addReplyLongLong(c,count);
+    }
+}
+
+/* BITPOS key bit [start [end [BIT|BYTE]]] */
+void bitposCommand(client *c) {
+    robj *o;
+    long long start, end;
+    long bit, strlen;
+    unsigned char *p;
+    char llbuf[LONG_STR_SIZE];
+    int isbit = 0, end_given = 0;
+    unsigned char first_byte_neg_mask = 0, last_byte_neg_mask = 0;
+
+    /* Parse the bit argument to understand what we are looking for, set
+     * or clear bits. */
+    if (getLongFromObjectOrReply(c,c->argv[2],&bit,NULL) != C_OK)
+        return;
+    if (bit != 0 && bit != 1) {
+        addReplyError(c, "The bit argument must be 1 or 0.");
+        return;
+    }
+
+    /* If the key does not exist, from our point of view it is an infinite
+     * array of 0 bits. If the user is looking for the first clear bit return 0,
+     * If the user is looking for the first set bit, return -1. */
+    if ((o = lookupKeyRead(c->db,c->argv[1])) == NULL) {
+        addReplyLongLong(c, bit ? -1 : 0);
+        return;
+    }
+    if (checkType(c,o,OBJ_STRING)) return;
+    p = getObjectReadOnlyString(o,&strlen,llbuf);
+
+    /* Parse start/end range if any. */
+    if (c->argc == 4 || c->argc == 5 || c->argc == 6) {
+        long long totlen = strlen;
+        /* Make sure we will not overflow */
+        serverAssert(totlen <= LLONG_MAX >> 3);
+        if (getLongLongFromObjectOrReply(c,c->argv[3],&start,NULL) != C_OK)
+            return;
+        if (c->argc == 6) {
+            if (!strcasecmp(c->argv[5]->ptr,"bit")) isbit = 1;
+            else if (!strcasecmp(c->argv[5]->ptr,"byte")) isbit = 0;
+            else {
+                addReplyErrorObject(c,shared.syntaxerr);
+                return;
+            }
+        }
+        if (c->argc >= 5) {
+            if (getLongLongFromObjectOrReply(c,c->argv[4],&end,NULL) != C_OK)
+                return;
+            end_given = 1;
+        } else {
+            if (isbit) end = (totlen<<3) + 7;
+            else end = totlen-1;
+        }
+        if (isbit) totlen <<= 3;
+        /* Convert negative indexes */
+        if (start < 0) start = totlen+start;
+        if (end < 0) end = totlen+end;
+        if (start < 0) start = 0;
+        if (end < 0) end = 0;
+        if (end >= totlen) end = totlen-1;
+        if (isbit && start <= end) {
+            /* Before converting bit offset to byte offset, create negative masks
+             * for the edges. */
+            first_byte_neg_mask = ~((1<<(8-(start&7)))-1) & 0xFF;
+            last_byte_neg_mask = (1<<(7-(end&7)))-1;
+            start >>= 3;
+            end >>= 3;
+        }
+    } else if (c->argc == 3) {
+        /* The whole string. */
+        start = 0;
+        end = strlen-1;
+    } else {
+        /* Syntax error. */
+        addReplyErrorObject(c,shared.syntaxerr);
+        return;
+    }
+
+    /* For empty ranges (start > end) we return -1 as an empty range does
+     * not contain a 0 nor a 1. */
+    if (start > end) {
+        addReplyLongLong(c, -1);
+    } else {
+        long bytes = end-start+1;
+        long long pos;
+        unsigned char tmpchar;
+        if (first_byte_neg_mask) {
+            if (bit) tmpchar = p[start] & ~first_byte_neg_mask;
+            else tmpchar = p[start] | first_byte_neg_mask;
+            /* Special case, there is only one byte */
+            if (last_byte_neg_mask && bytes == 1) {
+                if (bit) tmpchar = tmpchar & ~last_byte_neg_mask;
+                else tmpchar = tmpchar | last_byte_neg_mask;
+            }
+            pos = redisBitpos(&tmpchar,1,bit);
+            /* If there are no more bytes or we get valid pos, we can exit early */
+            if (bytes == 1 || (pos != -1 && pos != 8)) goto result;
+            start++;
+            bytes--;
+        }
+        /* If the last byte has not bits in the range, we should exclude it */
+        long curbytes = bytes - (last_byte_neg_mask ? 1 : 0);
+        if (curbytes > 0) {
+            pos = redisBitpos(p+start,curbytes,bit);
+            /* If there is no more bytes or we get valid pos, we can exit early */
+            if (bytes == curbytes || (pos != -1 && pos != (long long)curbytes<<3)) goto result;
+            start += curbytes;
+            bytes -= curbytes;
+        }
+        if (bit) tmpchar = p[end] & ~last_byte_neg_mask;
+        else tmpchar = p[end] | last_byte_neg_mask;
+        pos = redisBitpos(&tmpchar,1,bit);
+
+    result:
+        /* If we are looking for clear bits, and the user specified an exact
+         * range with start-end, we can't consider the right of the range as
+         * zero padded (as we do when no explicit end is given).
+         *
+         * So if redisBitpos() returns the first bit outside the range,
+         * we return -1 to the caller, to mean, in the specified range there
+         * is not a single "0" bit. */
+        if (end_given && bit == 0 && pos == (long long)bytes<<3) {
+            addReplyLongLong(c,-1);
+            return;
+        }
+        if (pos != -1) pos += (long long)start<<3; /* Adjust for the bytes we skipped. */
+        addReplyLongLong(c,pos);
+    }
+}
+
+/* BITFIELD key subcommand-1 arg ... subcommand-2 arg ... subcommand-N ...
+ *
+ * Supported subcommands:
+ *
+ * GET <type> <offset>
+ * SET <type> <offset> <value>
+ * INCRBY <type> <offset> <increment>
+ * OVERFLOW [WRAP|SAT|FAIL]
+ */
+
+#define BITFIELD_FLAG_NONE      0
+#define BITFIELD_FLAG_READONLY  (1<<0)
+
+struct bitfieldOp {
+    uint64_t offset;    /* Bitfield offset. */
+    int64_t i64;        /* Increment amount (INCRBY) or SET value */
+    int opcode;         /* Operation id. */
+    int owtype;         /* Overflow type to use. */
+    int bits;           /* Integer bitfield bits width. */
+    int sign;           /* True if signed, otherwise unsigned op. */
+};
+
+/* This implements both the BITFIELD command and the BITFIELD_RO command
+ * when flags is set to BITFIELD_FLAG_READONLY: in this case only the
+ * GET subcommand is allowed, other subcommands will return an error. */
+void bitfieldGeneric(client *c, int flags) {
+    robj *o;
+    uint64_t bitoffset;
+    int j, numops = 0, changes = 0, dirty = 0;
+    struct bitfieldOp *ops = NULL; /* Array of ops to execute at end. */
+    int owtype = BFOVERFLOW_WRAP; /* Overflow type. */
+    int readonly = 1;
+    uint64_t highest_write_offset = 0;
+
+    for (j = 2; j < c->argc; j++) {
+        int remargs = c->argc-j-1; /* Remaining args other than current. */
+        char *subcmd = c->argv[j]->ptr; /* Current command name. */
+        int opcode; /* Current operation code. */
+        long long i64 = 0;  /* Signed SET value. */
+        int sign = 0; /* Signed or unsigned type? */
+        int bits = 0; /* Bitfield width in bits. */
+
+        if (!strcasecmp(subcmd,"get") && remargs >= 2)
+            opcode = BITFIELDOP_GET;
+        else if (!strcasecmp(subcmd,"set") && remargs >= 3)
+            opcode = BITFIELDOP_SET;
+        else if (!strcasecmp(subcmd,"incrby") && remargs >= 3)
+            opcode = BITFIELDOP_INCRBY;
+        else if (!strcasecmp(subcmd,"overflow") && remargs >= 1) {
+            char *owtypename = c->argv[j+1]->ptr;
+            j++;
+            if (!strcasecmp(owtypename,"wrap"))
+                owtype = BFOVERFLOW_WRAP;
+            else if (!strcasecmp(owtypename,"sat"))
+                owtype = BFOVERFLOW_SAT;
+            else if (!strcasecmp(owtypename,"fail"))
+                owtype = BFOVERFLOW_FAIL;
+            else {
+                addReplyError(c,"Invalid OVERFLOW type specified");
+                zfree(ops);
+                return;
+            }
+            continue;
+        } else {
+            addReplyErrorObject(c,shared.syntaxerr);
+            zfree(ops);
+            return;
+        }
+
+        /* Get the type and offset arguments, common to all the ops. */
+        if (getBitfieldTypeFromArgument(c,c->argv[j+1],&sign,&bits) != C_OK) {
+            zfree(ops);
+            return;
+        }
+
+        if (getBitOffsetFromArgument(c,c->argv[j+2],&bitoffset,1,bits) != C_OK){
+            zfree(ops);
+            return;
+        }
+
+        if (opcode != BITFIELDOP_GET) {
+            readonly = 0;
+            if (highest_write_offset < bitoffset + bits - 1)
+                highest_write_offset = bitoffset + bits - 1;
+            /* INCRBY and SET require another argument. */
+            if (getLongLongFromObjectOrReply(c,c->argv[j+3],&i64,NULL) != C_OK){
+                zfree(ops);
+                return;
+            }
+        }
+
+        /* Populate the array of operations we'll process. */
+        ops = zrealloc(ops,sizeof(*ops)*(numops+1));
+        ops[numops].offset = bitoffset;
+        ops[numops].i64 = i64;
+        ops[numops].opcode = opcode;
+        ops[numops].owtype = owtype;
+        ops[numops].bits = bits;
+        ops[numops].sign = sign;
+        numops++;
+
+        j += 3 - (opcode == BITFIELDOP_GET);
+    }
+
+    if (readonly) {
+        /* Lookup for read is ok if key doesn't exit, but errors
+         * if it's not a string. */
+        o = lookupKeyRead(c->db,c->argv[1]);
+        if (o != NULL && checkType(c,o,OBJ_STRING)) {
+            zfree(ops);
+            return;
+        }
+    } else {
+        if (flags & BITFIELD_FLAG_READONLY) {
+            zfree(ops);
+            addReplyError(c, "BITFIELD_RO only supports the GET subcommand");
+            return;
+        }
+
+        /* Lookup by making room up to the farthest bit reached by
+         * this operation. */
+        if ((o = lookupStringForBitCommand(c,
+            highest_write_offset,&dirty)) == NULL) {
+            zfree(ops);
+            return;
+        }
+    }
+
+    addReplyArrayLen(c,numops);
+
+    /* Actually process the operations. */
+    for (j = 0; j < numops; j++) {
+        struct bitfieldOp *thisop = ops+j;
+
+        /* Execute the operation. */
+        if (thisop->opcode == BITFIELDOP_SET ||
+            thisop->opcode == BITFIELDOP_INCRBY)
+        {
+            /* SET and INCRBY: We handle both with the same code path
+             * for simplicity. SET return value is the previous value so
+             * we need fetch & store as well. */
+
+            /* We need two different but very similar code paths for signed
+             * and unsigned operations, since the set of functions to get/set
+             * the integers and the used variables types are different. */
+            if (thisop->sign) {
+                int64_t oldval, newval, wrapped, retval;
+                int overflow;
+
+                oldval = getSignedBitfield(o->ptr,thisop->offset,
+                        thisop->bits);
+
+                if (thisop->opcode == BITFIELDOP_INCRBY) {
+                    overflow = checkSignedBitfieldOverflow(oldval,
+                            thisop->i64,thisop->bits,thisop->owtype,&wrapped);
+                    newval = overflow ? wrapped : oldval + thisop->i64;
+                    retval = newval;
+                } else {
+                    newval = thisop->i64;
+                    overflow = checkSignedBitfieldOverflow(newval,
+                            0,thisop->bits,thisop->owtype,&wrapped);
+                    if (overflow) newval = wrapped;
+                    retval = oldval;
+                }
+
+                /* On overflow of type is "FAIL", don't write and return
+                 * NULL to signal the condition. */
+                if (!(overflow && thisop->owtype == BFOVERFLOW_FAIL)) {
+                    addReplyLongLong(c,retval);
+                    setSignedBitfield(o->ptr,thisop->offset,
+                                      thisop->bits,newval);
+
+                    if (dirty || (oldval != newval))
+                        changes++;
+                } else {
+                    addReplyNull(c);
+                }
+            } else {
+                /* Initialization of 'wrapped' is required to avoid
+                * false-positive warning "-Wmaybe-uninitialized" */
+                uint64_t oldval, newval, retval, wrapped = 0;
+                int overflow;
+
+                oldval = getUnsignedBitfield(o->ptr,thisop->offset,
+                        thisop->bits);
+
+                if (thisop->opcode == BITFIELDOP_INCRBY) {
+                    newval = oldval + thisop->i64;
+                    overflow = checkUnsignedBitfieldOverflow(oldval,
+                            thisop->i64,thisop->bits,thisop->owtype,&wrapped);
+                    if (overflow) newval = wrapped;
+                    retval = newval;
+                } else {
+                    newval = thisop->i64;
+                    overflow = checkUnsignedBitfieldOverflow(newval,
+                            0,thisop->bits,thisop->owtype,&wrapped);
+                    if (overflow) newval = wrapped;
+                    retval = oldval;
+                }
+                /* On overflow of type is "FAIL", don't write and return
+                 * NULL to signal the condition. */
+                if (!(overflow && thisop->owtype == BFOVERFLOW_FAIL)) {
+                    addReplyLongLong(c,retval);
+                    setUnsignedBitfield(o->ptr,thisop->offset,
+                                        thisop->bits,newval);
+
+                    if (dirty || (oldval != newval))
+                        changes++;
+                } else {
+                    addReplyNull(c);
+                }
+            }
+        } else {
+            /* GET */
+            unsigned char buf[9];
+            long strlen = 0;
+            unsigned char *src = NULL;
+            char llbuf[LONG_STR_SIZE];
+
+            if (o != NULL)
+                src = getObjectReadOnlyString(o,&strlen,llbuf);
+
+            /* For GET we use a trick: before executing the operation
+             * copy up to 9 bytes to a local buffer, so that we can easily
+             * execute up to 64 bit operations that are at actual string
+             * object boundaries. */
+            memset(buf,0,9);
+            int i;
+            uint64_t byte = thisop->offset >> 3;
+            for (i = 0; i < 9; i++) {
+                if (src == NULL || i+byte >= (uint64_t)strlen) break;
+                buf[i] = src[i+byte];
+            }
+
+            /* Now operate on the copied buffer which is guaranteed
+             * to be zero-padded. */
+            if (thisop->sign) {
+                int64_t val = getSignedBitfield(buf,thisop->offset-(byte*8),
+                                            thisop->bits);
+                addReplyLongLong(c,val);
+            } else {
+                uint64_t val = getUnsignedBitfield(buf,thisop->offset-(byte*8),
+                                            thisop->bits);
+                addReplyLongLong(c,val);
+            }
+        }
+    }
+
+    if (changes) {
+        signalModifiedKey(c,c->db,c->argv[1]);
+        notifyKeyspaceEvent(NOTIFY_STRING,"setbit",c->argv[1],c->db->id);
+        server.dirty += changes;
+    }
+    zfree(ops);
+}
+
+void bitfieldCommand(client *c) {
+    bitfieldGeneric(c, BITFIELD_FLAG_NONE);
+}
+
+void bitfieldroCommand(client *c) {
+    bitfieldGeneric(c, BITFIELD_FLAG_READONLY);
+}