PHP中的gzcompress、gzdeflate、gzencode函数详解

<?php
$url = 'http://jb51.net';
$s1 = gzdeflate($url, 1);
$s2 = gzencode($url, 1, ZLIB_ENCODING_RAW);
if (strcmp($s1, $s2) == 0) echo 'the same';
?>

#define PHP_ZLIB_ENCODE_FUNC(name, default_encoding) \
static PHP_FUNCTION(name) \
{ \
    char *in_buf, *out_buf; \
    int in_len; \
    size_t out_len; \
    long level = -1; \
    long encoding = default_encoding; \
    if (default_encoding) { \
        if (SUCCESS != zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s|ll", &in_buf, &in_len, &level, &encoding)) { \
            return; \
        } \
    } else { \
        if (SUCCESS != zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "sl|l", &in_buf, &in_len, &encoding, &level)) { \
            return; \
        } \
    } \
    if (level < -1 || level > 9) { \
        php_error_docref(NULL TSRMLS_CC, E_WARNING, "compression level (%ld) must be within -1..9", level); \
        RETURN_FALSE; \
    } \
    switch (encoding) { \
        case PHP_ZLIB_ENCODING_RAW: \
        case PHP_ZLIB_ENCODING_GZIP: \
        case PHP_ZLIB_ENCODING_DEFLATE: \
            break; \
        default: \
            php_error_docref(NULL TSRMLS_CC, E_WARNING, "encoding mode must be either ZLIB_ENCODING_RAW, ZLIB_ENCODING_GZIP or ZLIB_ENCODING_DEFLATE"); \
            RETURN_FALSE; \
    } \
    if (SUCCESS != php_zlib_encode(in_buf, in_len, &out_buf, &out_len, encoding, level TSRMLS_CC)) { \
        RETURN_FALSE; \
    } \
    RETURN_STRINGL(out_buf, out_len, 0); \
}

/* NOTE: The naming of these userland functions was quite unlucky */
/* {{{ proto binary gzdeflate(binary data[, int level = -1[, int encoding = ZLIB_ENCODING_RAW])
   Encode data with the raw deflate encoding */
PHP_ZLIB_ENCODE_FUNC(gzdeflate, PHP_ZLIB_ENCODING_RAW);
/* }}} */

/* {{{ proto binary gzencode(binary data[, int level = -1[, int encoding = ZLIB_ENCODING_GZIP])
   Encode data with the gzip encoding */
PHP_ZLIB_ENCODE_FUNC(gzencode, PHP_ZLIB_ENCODING_GZIP);
/* }}} */

/* {{{ proto binary gzcompress(binary data[, int level = -1[, int encoding = ZLIB_ENCODING_DEFLATE])
   Encode data with the zlib encoding */
PHP_ZLIB_ENCODE_FUNC(gzcompress, PHP_ZLIB_ENCODING_DEFLATE);
/* }}} */