Redis source code reading numeric to longlong2str, redislonglong2str

Redis source code reading numeric to longlong2str, redislonglong2str
Redis converts long to string at the underlying layer for storage. The main function is in the sds module. The following two functions convert long to char and unsiged long to char. The general idea is: 1. Convert the value from the end to the first to a character, 2 to calculate the length, and add the Terminator. 3. Reverse the string. 4 if the long type is used, a negative number should be considered.

int sdsll2str(char *s, long long value) {    char *p, aux;    unsigned long long v;    size_t l;    /* Generate the string representation, this method produces     * an reversed string. */    v = (value < 0) ? -value : value;    p = s;    do {        *p++ = '0'+(v%10);        v /= 10;    } while(v);    if (value < 0) *p++ = '-';    /* Compute length and add null term. */    l = p-s;    *p = '\0';    /* Reverse the string. */    p--;    while(s < p) {        aux = *s;        *s = *p;        *p = aux;        s++;        p--;    }    return l;}/* Identical sdsll2str(), but for unsigned long long type. */int sdsull2str(char *s, unsigned long long v) {    char *p, aux;    size_t l;    /* Generate the string representation, this method produces     * an reversed string. */    p = s;    do {        *p++ = '0'+(v%10);        v /= 10;    } while(v);    /* Compute length and add null term. */    l = p-s;    *p = '\0';    /* Reverse the string. */    p--;    while(s < p) {        aux = *s;        *s = *p;        *p = aux;        s++;        p--;    }    return l;}