Simplify iconv_strpos implementation

Use a separate "reverse" flag to determine search direction,
using offset == -1 to indicate this is is confusing. I initially
thought the code was trying to handle negative offsets.

Also deduplicate the forward and reverse cases, they really only differ
in one place.

diff --git a/ext/iconv/iconv.c b/ext/iconv/iconv.c
index 3a4399d350556c9c11fecaa114e7a79e736ea5fe..89f2ffb37fdfe4f73254a42aa79663b5c69d7160 100644 (file)
--- a/ext/iconv/iconv.c
+++ b/ext/iconv/iconv.c
@@ -117,8 +117,6 @@ static php_iconv_err_t _php_iconv_strlen(size_t *pretval, const char *str, size_
 
 static php_iconv_err_t _php_iconv_substr(smart_str *pretval, const char *str, size_t nbytes, zend_long offset, zend_long len, const char *enc);
 
-static php_iconv_err_t _php_iconv_strpos(size_t *pretval, const char *haystk, size_t haystk_nbytes, const char *ndl, size_t ndl_nbytes, zend_long offset, const char *enc);
-
 static php_iconv_err_t _php_iconv_mime_encode(smart_str *pretval, const char *fname, size_t fname_nbytes, const char *fval, size_t fval_nbytes, size_t max_line_len, const char *lfchars, php_iconv_enc_scheme_t enc_scheme, const char *out_charset, const char *enc);
 
 static php_iconv_err_t _php_iconv_mime_decode(smart_str *pretval, const char *str, size_t str_nbytes, const char *enc, const char **next_pos, int mode);
@@ -748,7 +746,7 @@ static php_iconv_err_t _php_iconv_substr(smart_str *pretval,
 static php_iconv_err_t _php_iconv_strpos(size_t *pretval,
        const char *haystk, size_t haystk_nbytes,
        const char *ndl, size_t ndl_nbytes,
-       zend_long offset, const char *enc)
+       size_t offset, const char *enc, bool reverse)
 {
        char buf[GENERIC_SUPERSET_NBYTES];
 
@@ -829,49 +827,7 @@ static php_iconv_err_t _php_iconv_strpos(size_t *pretval,
                                        break;
                        }
                }
-               if (offset >= 0) {
-                       if (cnt >= (size_t)offset) {
-                               if (_php_iconv_memequal(buf, ndl_buf_p, sizeof(buf))) {
-                                       if (match_ofs == (size_t)-1) {
-                                               match_ofs = cnt;
-                                       }
-                                       ndl_buf_p += GENERIC_SUPERSET_NBYTES;
-                                       ndl_buf_left -= GENERIC_SUPERSET_NBYTES;
-                                       if (ndl_buf_left == 0) {
-                                               *pretval = match_ofs;
-                                               break;
-                                       }
-                               } else {
-                                       size_t i, j, lim;
-
-                                       i = 0;
-                                       j = GENERIC_SUPERSET_NBYTES;
-                                       lim = (size_t)(ndl_buf_p - ZSTR_VAL(ndl_buf));
-
-                                       while (j < lim) {
-                                               if (_php_iconv_memequal(&ZSTR_VAL(ndl_buf)[j], &ZSTR_VAL(ndl_buf)[i],
-                                                          GENERIC_SUPERSET_NBYTES)) {
-                                                       i += GENERIC_SUPERSET_NBYTES;
-                                               } else {
-                                                       j -= i;
-                                                       i = 0;
-                                               }
-                                               j += GENERIC_SUPERSET_NBYTES;
-                                       }
-
-                                       if (_php_iconv_memequal(buf, &ZSTR_VAL(ndl_buf)[i], sizeof(buf))) {
-                                               match_ofs += (lim - i) / GENERIC_SUPERSET_NBYTES;
-                                               i += GENERIC_SUPERSET_NBYTES;
-                                               ndl_buf_p = &ZSTR_VAL(ndl_buf)[i];
-                                               ndl_buf_left = ZSTR_LEN(ndl_buf) - i;
-                                       } else {
-                                               match_ofs = (size_t)-1;
-                                               ndl_buf_p = ZSTR_VAL(ndl_buf);
-                                               ndl_buf_left = ZSTR_LEN(ndl_buf);
-                                       }
-                               }
-                       }
-               } else {
+               if (cnt >= offset) {
                        if (_php_iconv_memequal(buf, ndl_buf_p, sizeof(buf))) {
                                if (match_ofs == (size_t)-1) {
                                        match_ofs = cnt;
@@ -880,9 +836,15 @@ static php_iconv_err_t _php_iconv_strpos(size_t *pretval,
                                ndl_buf_left -= GENERIC_SUPERSET_NBYTES;
                                if (ndl_buf_left == 0) {
                                        *pretval = match_ofs;
-                                       ndl_buf_p = ZSTR_VAL(ndl_buf);
-                                       ndl_buf_left = ZSTR_LEN(ndl_buf);
-                                       match_ofs = -1;
+                                       if (reverse) {
+                                               /* If searching backward, continue trying to find a later match. */
+                                               ndl_buf_p = ZSTR_VAL(ndl_buf);
+                                               ndl_buf_left = ZSTR_LEN(ndl_buf);
+                                               match_ofs = -1;
+                                       } else {
+                                               /* If searching forward, stop at first match. */
+                                               break;
+                                       }
                                }
                        } else {
                                size_t i, j, lim;
@@ -1928,8 +1890,9 @@ PHP_FUNCTION(iconv_strpos)
                RETURN_FALSE;
        }
 
-       err = _php_iconv_strpos(&retval, ZSTR_VAL(haystk), ZSTR_LEN(haystk), ZSTR_VAL(ndl), ZSTR_LEN(ndl),
-                               offset, charset);
+       err = _php_iconv_strpos(
+               &retval, ZSTR_VAL(haystk), ZSTR_LEN(haystk), ZSTR_VAL(ndl), ZSTR_LEN(ndl),
+               offset, charset, /* reverse */ false);
        _php_iconv_show_error(err, GENERIC_SUPERSET_NAME, charset);
 
        if (err == PHP_ICONV_ERR_SUCCESS && retval != (size_t)-1) {
@@ -1969,8 +1932,9 @@ PHP_FUNCTION(iconv_strrpos)
                RETURN_FALSE;
        }
 
-       err = _php_iconv_strpos(&retval, ZSTR_VAL(haystk), ZSTR_LEN(haystk), ZSTR_VAL(ndl), ZSTR_LEN(ndl),
-                               -1, charset);
+       err = _php_iconv_strpos(
+               &retval, ZSTR_VAL(haystk), ZSTR_LEN(haystk), ZSTR_VAL(ndl), ZSTR_LEN(ndl),
+               /* offset */ 0, charset, /* reserve */ true);
        _php_iconv_show_error(err, GENERIC_SUPERSET_NAME, charset);
 
        if (err == PHP_ICONV_ERR_SUCCESS && retval != (size_t)-1) {