diff options
Diffstat (limited to 'jv.c')
| -rw-r--r-- | jv.c | 57 |
1 files changed, 57 insertions, 0 deletions
@@ -687,6 +687,63 @@ const char* jv_string_value(jv j) { return jvp_string_ptr(&j.val.nontrivial)->data; } +jv jv_string_slice(jv j, int start, int end) { + assert(jv_get_kind(j) == JV_KIND_STRING); + const char *s = jv_string_value(j); + int len = jv_string_length_bytes(jv_copy(j)); + int i; + const char *p, *e; + int c; + jv res; + + if (start < 0) start = len + start; + if (end < 0) end = len + end; + + if (start < 0) start = 0; + if (start > len) start = len; + if (end > len) end = len; + if (end < start) end = start; + if (start < 0 || start > end || end > len) + return jv_invalid_with_msg(jv_string("Invalid string slice indices")); + assert(0 <= start && start <= end && end <= len); + + /* Look for byte offset corresponding to start codepoints */ + for (p = s, i = 0; i < start; i++) { + p = jvp_utf8_next(p, s + len, &c); + if (p == NULL) { + jv_free(j); + return jv_string_empty(16); + } + if (c == -1) { + jv_free(j); + return jv_invalid_with_msg(jv_string("Invalid UTF-8 string")); + } + } + /* Look for byte offset corresponding to end codepoints */ + for (e = p; e != NULL && i < end; i++) { + e = jvp_utf8_next(e, s + len, &c); + if (e == NULL) { + e = s + len; + break; + } + if (c == -1) { + jv_free(j); + return jv_invalid_with_msg(jv_string("Invalid UTF-8 string")); + } + } + + /* + * NOTE: Ideally we should do here what jvp_array_slice() does instead + * of allocating a new string as we do! However, we assume NUL- + * terminated strings all over, and in the jv API, so for now we waste + * memory like a drunken navy programmer. There's probably nothing we + * can do about it. + */ + res = jv_string_sized(p, e - p); + jv_free(j); + return res; +} + jv jv_string_concat(jv a, jv b) { jvp_string* sb = jvp_string_ptr(&b.val.nontrivial); jvp_string_append(&a.val.nontrivial, sb->data, jvp_string_length(sb)); |