brainstorming with myself in dscache.c comments

[redis.git] / src / util.c

#include "redis.h"
#include <ctype.h>
#include <limits.h>

/* Glob-style pattern matching. */
int stringmatchlen(const char *pattern, int patternLen,
        const char *string, int stringLen, int nocase)
{
    while(patternLen) {
        switch(pattern[0]) {
        case '*':
            while (pattern[1] == '*') {
                pattern++;
                patternLen--;
            }
            if (patternLen == 1)
                return 1; /* match */
            while(stringLen) {
                if (stringmatchlen(pattern+1, patternLen-1,
                            string, stringLen, nocase))
                    return 1; /* match */
                string++;
                stringLen--;
            }
            return 0; /* no match */
            break;
        case '?':
            if (stringLen == 0)
                return 0; /* no match */
            string++;
            stringLen--;
            break;
        case '[':
        {
            int not, match;

            pattern++;
            patternLen--;
            not = pattern[0] == '^';
            if (not) {
                pattern++;
                patternLen--;
            }
            match = 0;
            while(1) {
                if (pattern[0] == '\\') {
                    pattern++;
                    patternLen--;
                    if (pattern[0] == string[0])
                        match = 1;
                } else if (pattern[0] == ']') {
                    break;
                } else if (patternLen == 0) {
                    pattern--;
                    patternLen++;
                    break;
                } else if (pattern[1] == '-' && patternLen >= 3) {
                    int start = pattern[0];
                    int end = pattern[2];
                    int c = string[0];
                    if (start > end) {
                        int t = start;
                        start = end;
                        end = t;
                    }
                    if (nocase) {
                        start = tolower(start);
                        end = tolower(end);
                        c = tolower(c);
                    }
                    pattern += 2;
                    patternLen -= 2;
                    if (c >= start && c <= end)
                        match = 1;
                } else {
                    if (!nocase) {
                        if (pattern[0] == string[0])
                            match = 1;
                    } else {
                        if (tolower((int)pattern[0]) == tolower((int)string[0]))
                            match = 1;
                    }
                }
                pattern++;
                patternLen--;
            }
            if (not)
                match = !match;
            if (!match)
                return 0; /* no match */
            string++;
            stringLen--;
            break;
        }
        case '\\':
            if (patternLen >= 2) {
                pattern++;
                patternLen--;
            }
            /* fall through */
        default:
            if (!nocase) {
                if (pattern[0] != string[0])
                    return 0; /* no match */
            } else {
                if (tolower((int)pattern[0]) != tolower((int)string[0]))
                    return 0; /* no match */
            }
            string++;
            stringLen--;
            break;
        }
        pattern++;
        patternLen--;
        if (stringLen == 0) {
            while(*pattern == '*') {
                pattern++;
                patternLen--;
            }
            break;
        }
    }
    if (patternLen == 0 && stringLen == 0)
        return 1;
    return 0;
}

int stringmatch(const char *pattern, const char *string, int nocase) {
    return stringmatchlen(pattern,strlen(pattern),string,strlen(string),nocase);
}

/* Convert a string representing an amount of memory into the number of
 * bytes, so for instance memtoll("1Gi") will return 1073741824 that is
 * (1024*1024*1024).
 *
 * On parsing error, if *err is not NULL, it's set to 1, otherwise it's
 * set to 0 */
long long memtoll(const char *p, int *err) {
    const char *u;
    char buf[128];
    long mul; /* unit multiplier */
    long long val;
    unsigned int digits;

    if (err) *err = 0;
    /* Search the first non digit character. */
    u = p;
    if (*u == '-') u++;
    while(*u && isdigit(*u)) u++;
    if (*u == '\0' || !strcasecmp(u,"b")) {
        mul = 1;
    } else if (!strcasecmp(u,"k")) {
        mul = 1000;
    } else if (!strcasecmp(u,"kb")) {
        mul = 1024;
    } else if (!strcasecmp(u,"m")) {
        mul = 1000*1000;
    } else if (!strcasecmp(u,"mb")) {
        mul = 1024*1024;
    } else if (!strcasecmp(u,"g")) {
        mul = 1000L*1000*1000;
    } else if (!strcasecmp(u,"gb")) {
        mul = 1024L*1024*1024;
    } else {
        if (err) *err = 1;
        mul = 1;
    }
    digits = u-p;
    if (digits >= sizeof(buf)) {
        if (err) *err = 1;
        return LLONG_MAX;
    }
    memcpy(buf,p,digits);
    buf[digits] = '\0';
    val = strtoll(buf,NULL,10);
    return val*mul;
}

/* Convert a long long into a string. Returns the number of
 * characters needed to represent the number, that can be shorter if passed
 * buffer length is not enough to store the whole number. */
int ll2string(char *s, size_t len, long long value) {
    char buf[32], *p;
    unsigned long long v;
    size_t l;

    if (len == 0) return 0;
    v = (value < 0) ? -value : value;
    p = buf+31; /* point to the last character */
    do {
        *p-- = '0'+(v%10);
        v /= 10;
    } while(v);
    if (value < 0) *p-- = '-';
    p++;
    l = 32-(p-buf);
    if (l+1 > len) l = len-1; /* Make sure it fits, including the nul term */
    memcpy(s,p,l);
    s[l] = '\0';
    return l;
}

/* Check if the sds string 's' can be represented by a long long
 * (that is, is a number that fits into long without any other space or
 * character before or after the digits, so that converting this number
 * back to a string will result in the same bytes as the original string).
 *
 * If so, the function returns REDIS_OK and *llongval is set to the value
 * of the number. Otherwise REDIS_ERR is returned */
int isStringRepresentableAsLongLong(sds s, long long *llongval) {
    char buf[32], *endptr;
    long long value;
    int slen;

    value = strtoll(s, &endptr, 10);
    if (endptr[0] != '\0') return REDIS_ERR;
    slen = ll2string(buf,32,value);

    /* If the number converted back into a string is not identical
     * then it's not possible to encode the string as integer */
    if (sdslen(s) != (unsigned)slen || memcmp(buf,s,slen)) return REDIS_ERR;
    if (llongval) *llongval = value;
    return REDIS_OK;
}

int isStringRepresentableAsLong(sds s, long *longval) {
    long long ll;

    if (isStringRepresentableAsLongLong(s,&ll) == REDIS_ERR) return REDIS_ERR;
    if (ll < LONG_MIN || ll > LONG_MAX) return REDIS_ERR;
    *longval = (long)ll;
    return REDIS_OK;
}

int isObjectRepresentableAsLongLong(robj *o, long long *llongval) {
    redisAssert(o->type == REDIS_STRING);
    if (o->encoding == REDIS_ENCODING_INT) {
        if (llongval) *llongval = (long) o->ptr;
        return REDIS_OK;
    } else {
        return isStringRepresentableAsLongLong(o->ptr,llongval);
    }
}