ngx_string.c

Nginx是一个高性能的HTTP和反向代理服务器

ngx_strncasecmp(u_char *s1, u_char *s2, size_t n)
{
    ngx_uint_t  c1, c2;

    while (n) {
        c1 = (ngx_uint_t) *s1++;
        c2 = (ngx_uint_t) *s2++;

        c1  = (c1 >= 'A' && c1 <= 'Z') ? (c1 | 0x20) : c1;
        c2  = (c2 >= 'A' && c2 <= 'Z') ? (c2 | 0x20) : c2;

        if (c1 == c2) {

            if (c1) {
                n--;
                continue;
            }

            return 0;
        }

        return c1 - c2;
    }

    return 0;
}


u_char *
ngx_strnstr(u_char *s1, char *s2, size_t len)
{
    u_char  c1, c2;
    size_t  n;

    c2 = *(u_char *) s2++;

    n = ngx_strlen(s2);

    do {
        do {
            if (len-- == 0) {
                return NULL;
            }

            c1 = *s1++;

            if (c1 == 0) {
                return NULL;
            }

        } while (c1 != c2);

        if (n > len) {
            return NULL;
        }

    } while (ngx_strncmp(s1, (u_char *) s2, n) != 0);

    return --s1;
}


/*
 * ngx_strstrn() and ngx_strcasestrn() are intended to search for static
 * substring with known length in null-terminated string. The argument n
 * must be length of the second substring - 1.
 */

u_char *
ngx_strstrn(u_char *s1, char *s2, size_t n)
{
    u_char  c1, c2;

    c2 = *(u_char *) s2++;

    do {
        do {
            c1 = *s1++;

            if (c1 == 0) {
                return NULL;
            }

        } while (c1 != c2);

    } while (ngx_strncmp(s1, (u_char *) s2, n) != 0);

    return --s1;
}


u_char *
ngx_strcasestrn(u_char *s1, char *s2, size_t n)
{
    ngx_uint_t  c1, c2;

    c2 = (ngx_uint_t) *s2++;
    c2  = (c2 >= 'A' && c2 <= 'Z') ? (c2 | 0x20) : c2;

    do {
        do {
            c1 = (ngx_uint_t) *s1++;

            if (c1 == 0) {
                return NULL;
            }

            c1  = (c1 >= 'A' && c1 <= 'Z') ? (c1 | 0x20) : c1;

        } while (c1 != c2);

    } while (ngx_strncasecmp(s1, (u_char *) s2, n) != 0);

    return --s1;
}


ngx_int_t
ngx_rstrncmp(u_char *s1, u_char *s2, size_t n)
{
    if (n == 0) {
        return 0;
    }

    n--;

    for ( ;; ) {
        if (s1[n] != s2[n]) {
            return s1[n] - s2[n];
        }

        if (n == 0) {
            return 0;
        }

        n--;
    }
}


ngx_int_t
ngx_rstrncasecmp(u_char *s1, u_char *s2, size_t n)
{
    u_char  c1, c2;

    if (n == 0) {
        return 0;
    }

    n--;

    for ( ;; ) {
        c1 = s1[n];
        if (c1 >= 'a' && c1 <= 'z') {
            c1 -= 'a' - 'A';
        }

        c2 = s2[n];
        if (c2 >= 'a' && c2 <= 'z') {
            c2 -= 'a' - 'A';
        }

        if (c1 != c2) {
            return c1 - c2;
        }

        if (n == 0) {
            return 0;
        }

        n--;
    }
}


ngx_int_t
ngx_memn2cmp(u_char *s1, u_char *s2, size_t n1, size_t n2)
{
    size_t     n;
    ngx_int_t  m, z;

    if (n1 <= n2) {
        n = n1;
        z = -1;

    } else {
        n = n2;
        z = 1;
    }

    m = ngx_memcmp(s1, s2, n);

    if (m || n1 == n2) {
        return m;
    }

    return z;
}


ngx_int_t
ngx_atoi(u_char *line, size_t n)
{
    ngx_int_t  value;

    if (n == 0) {
        return NGX_ERROR;
    }

    for (value = 0; n--; line++) {
        if (*line < '0' || *line > '9') {
            return NGX_ERROR;
        }

        value = value * 10 + (*line - '0');
    }

    if (value < 0) {
        return NGX_ERROR;

    } else {
        return value;
    }
}


ssize_t
ngx_atosz(u_char *line, size_t n)
{
    ssize_t  value;

    if (n == 0) {
        return NGX_ERROR;
    }

    for (value = 0; n--; line++) {
        if (*line < '0' || *line > '9') {
            return NGX_ERROR;
        }

        value = value * 10 + (*line - '0');
    }

    if (value < 0) {
        return NGX_ERROR;

    } else {
        return value;
    }
}


off_t
ngx_atoof(u_char *line, size_t n)
{
    off_t  value;

    if (n == 0) {
        return NGX_ERROR;
    }

    for (value = 0; n--; line++) {
        if (*line < '0' || *line > '9') {
            return NGX_ERROR;
        }

        value = value * 10 + (*line - '0');
    }

    if (value < 0) {
        return NGX_ERROR;

    } else {
        return value;
    }
}


time_t
ngx_atotm(u_char *line, size_t n)
{
    time_t  value;

    if (n == 0) {
        return NGX_ERROR;
    }

    for (value = 0; n--; line++) {
        if (*line < '0' || *line > '9') {
            return NGX_ERROR;
        }

        value = value * 10 + (*line - '0');
    }

    if (value < 0) {
        return NGX_ERROR;

    } else {
        return value;
    }
}


ngx_int_t
ngx_hextoi(u_char *line, size_t n)
{
    u_char     c, ch;
    ngx_int_t  value;

    if (n == 0) {
        return NGX_ERROR;
    }

    for (value = 0; n--; line++) {
        ch = *line;

        if (ch >= '0' && ch <= '9') {
            value = value * 16 + (ch - '0');
            continue;
        }

        c = (u_char) (ch | 0x20);

        if (c >= 'a' && c <= 'f') {
            value = value * 16 + (c - 'a' + 10);
            continue;
        }

        return NGX_ERROR;
    }

    if (value < 0) {
        return NGX_ERROR;

    } else {
        return value;
    }
}


u_char *
ngx_hex_dump(u_char *dst, u_char *src, size_t len)
{
    static u_char  hex[] = "0123456789abcdef";

    while (len--) {
        *dst++ = hex[*src >> 4];
        *dst++ = hex[*src++ & 0xf];
    }

    return dst;
}


void
ngx_encode_base64(ngx_str_t *dst, ngx_str_t *src)
{
    u_char         *d, *s;
    size_t          len;
    static u_char   basis64[] =
            "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

    len = src->len;
    s = src->data;
    d = dst->data;

    while (len > 2) {
        *d++ = basis64[(s[0] >> 2) & 0x3f];
        *d++ = basis64[((s[0] & 3) << 4) | (s[1] >> 4)];
        *d++ = basis64[((s[1] & 0x0f) << 2) | (s[2] >> 6)];
        *d++ = basis64[s[2] & 0x3f];

        s += 3;
        len -= 3;
    }

    if (len) {
        *d++ = basis64[(s[0] >> 2) & 0x3f];

        if (len == 1) {
            *d++ = basis64[(s[0] & 3) << 4];
            *d++ = '=';

        } else {
            *d++ = basis64[((s[0] & 3) << 4) | (s[1] >> 4)];
            *d++ = basis64[(s[1] & 0x0f) << 2];
        }

        *d++ = '=';
    }

    dst->len = d - dst->data;
}


ngx_int_t
ngx_decode_base64(ngx_str_t *dst, ngx_str_t *src)
{
    size_t          len;
    u_char         *d, *s;
    static u_char   basis64[] = {
        77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
        77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
        77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 62, 77, 77, 77, 63,
        52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 77, 77, 77, 77, 77, 77,
        77,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
        15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 77, 77, 77, 77, 77,
        77, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
        41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 77, 77, 77, 77, 77,

        77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
        77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
        77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
        77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
        77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
        77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
        77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
        77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77
    };

    for (len = 0; len < src->len; len++) {
        if (src->data[len] == '=') {
            break;
        }

        if (basis64[src->data[len]] == 77) {
            return NGX_ERROR;
        }
    }

    if (len % 4 == 1) {
        return NGX_ERROR;
    }

    s = src->data;
    d = dst->data;

    while (len > 3) {
        *d++ = (u_char) (basis64[s[0]] << 2 | basis64[s[1]] >> 4);
        *d++ = (u_char) (basis64[s[1]] << 4 | basis64[s[2]] >> 2);
        *d++ = (u_char) (basis64[s[2]] << 6 | basis64[s[3]]);

        s += 4;
        len -= 4;
    }

    if (len > 1) {
        *d++ = (u_char) (basis64[s[0]] << 2 | basis64[s[1]] >> 4);
    }

    if (len > 2) {
        *d++ = (u_char) (basis64[s[1]] << 4 | basis64[s[2]] >> 2);
    }

    dst->len = d - dst->data;

    return NGX_OK;
}


/*
 * ngx_utf_decode() decodes two and more bytes UTF sequences only
 * the return values:
 *    0x80 - 0x10ffff         valid character
 *    0x10ffff - 0xfffffffd   invalid sequence
 *    0xfffffffe              incomplete sequence
 *    0xffffffff              error
 */

uint32_t
ngx_utf_decode(u_char **p, size_t n)
{
    size_t    len;
    uint32_t  u, i, valid;

    u = **p;

    if (u > 0xf0) {

        u &= 0x07;
        valid = 0xffff;
        len = 3;

    } else if (u > 0xe0) {

        u &= 0x0f;
        valid = 0x7ff;
        len = 2;

    } else if (u > 0xc0) {