/* vi: set sw=4 ts=4: */
/*
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
#include "libbb.h"

/*
 * Return NULL if string is not prefixed with key. Return pointer to the
 * first character in string after the prefix key. If key is an empty string,
 * return pointer to the beginning of string.
 */
char* FAST_FUNC is_prefixed_with(const char *string, const char *key)
{
#if 0   /* Two passes over key - probably slower */
        int len = strlen(key);
        if (strncmp(string, key, len) == 0)
                return string + len;
        return NULL;
#else   /* Open-coded */
        while (*key != '\0') {
                if (*key != *string)
                        return NULL;
                key++;
                string++;
        }
        return (char*)string;
#endif
}

/*
 * Return NULL if string is not suffixed with key. Return pointer to the
 * beginning of prefix key in string. If key is an empty string return pointer
 * to the end of string.
 */
char* FAST_FUNC is_suffixed_with(const char *string, const char *key)
{
        size_t key_len = strlen(key);
        ssize_t len_diff = strlen(string) - key_len;

        if (len_diff >= 0) {
                string += len_diff;
                if (strcmp(string, key) == 0) {
                        return (char*)string;
                }
        }

        return NULL;
}

/* returns the array index of the string */
/* (index of first match is returned, or -1) */
int FAST_FUNC index_in_str_array(const char *const string_array[], const char *key)
{
        int i;

        for (i = 0; string_array[i] != 0; i++) {
                if (strcmp(string_array[i], key) == 0) {
                        return i;
                }
        }
        return -1;
}

int FAST_FUNC index_in_strings(const char *strings, const char *key)
{
        int j, idx = 0;

        while (*strings) {
                /* Do we see "key\0" at current position in strings? */
                for (j = 0; *strings == key[j]; ++j) {
                        if (*strings++ == '\0') {
                                //bb_error_msg("found:'%s' i:%u", key, idx);
                                return idx; /* yes */
                        }
                }
                /* No.  Move to the start of the next string. */
                while (*strings++ != '\0')
                        continue;
                idx++;
        }
        return -1;
}

/* returns the array index of the string, even if it matches only a beginning */
/* (index of first match is returned, or -1) */
#ifdef UNUSED
int FAST_FUNC index_in_substr_array(const char *const string_array[], const char *key)
{
        int i;
        if (key[0]) {
                for (i = 0; string_array[i] != 0; i++) {
                        if (is_prefixed_with(string_array[i], key)) {
                                return i;
                        }
                }
        }
        return -1;
}
#endif

int FAST_FUNC index_in_substrings(const char *strings, const char *key)
{
        int matched_idx = -1;
        const int len = strlen(key);

        if (len) {
                int idx = 0;
                while (*strings) {
                        if (strncmp(strings, key, len) == 0) {
                                if (strings[len] == '\0')
                                        return idx; /* exact match */
                                if (matched_idx >= 0)
                                        return -1; /* ambiguous match */
                                matched_idx = idx;
                        }
                        strings += strlen(strings) + 1; /* skip NUL */
                        idx++;
                }
        }
        return matched_idx;
}

const char* FAST_FUNC nth_string(const char *strings, int n)
{
        while (n) {
                if (*strings++ == '\0') {
                        if (*strings == '\0') /* reached end of strings */
                                break;
                        n--;
                }
        }
        return strings;
}

#ifdef UNUSED_SO_FAR /* only brctl.c needs it yet */
/* Returns 0 for no, 1 for yes or a negative value on error.  */
smallint FAST_FUNC yesno(const char *str)
{
        static const char no_yes[] ALIGN1 =
                "0\0" "off\0" "no\0"
                "1\0" "on\0" "yes\0";
        int ret = index_in_substrings(no_yes, str);
        return ret / 3;
}
#endif

#if ENABLE_UNIT_TEST

BBUNIT_DEFINE_TEST(is_prefixed_with)
{
        BBUNIT_ASSERT_STREQ(" bar", is_prefixed_with("foo bar", "foo"));
        BBUNIT_ASSERT_STREQ("bar", is_prefixed_with("foo bar", "foo "));
        BBUNIT_ASSERT_STREQ("", is_prefixed_with("foo", "foo"));
        BBUNIT_ASSERT_STREQ("foo", is_prefixed_with("foo", ""));
        BBUNIT_ASSERT_STREQ("", is_prefixed_with("", ""));

        BBUNIT_ASSERT_NULL(is_prefixed_with("foo", "bar foo"));
        BBUNIT_ASSERT_NULL(is_prefixed_with("foo foo", "bar"));
        BBUNIT_ASSERT_NULL(is_prefixed_with("", "foo"));

        BBUNIT_ENDTEST;
}

BBUNIT_DEFINE_TEST(is_suffixed_with)
{
        BBUNIT_ASSERT_STREQ("bar", is_suffixed_with("foo bar", "bar"));
        BBUNIT_ASSERT_STREQ("foo", is_suffixed_with("foo", "foo"));
        BBUNIT_ASSERT_STREQ("", is_suffixed_with("foo", ""));
        BBUNIT_ASSERT_STREQ("", is_suffixed_with("", ""));
        BBUNIT_ASSERT_STREQ("foo", is_suffixed_with("barfoofoo", "foo"));

        BBUNIT_ASSERT_NULL(is_suffixed_with("foo", "bar foo"));
        BBUNIT_ASSERT_NULL(is_suffixed_with("foo foo", "bar"));
        BBUNIT_ASSERT_NULL(is_suffixed_with("", "foo"));

        BBUNIT_ENDTEST;
}

#endif /* ENABLE_UNIT_TEST */