STC zsview: Zero-terminated UTF8 String View

The type zsview is a zero-terminated and utf8-iterable string view. It refers to a constant contiguous sequence of char-elements with the first element of the sequence at position zero. The implementation holds two members: a pointer to constant char and a size. See csview for a non zero-terminated string view/span type.

Because zsview is zero-terminated, it can be an efficient replacent for const char*. E.g., the .str char* pointer can safely be passed to c-api's which expects standard zero terminated c-strings. It never allocates memory, and therefore need not be destructed. Its lifetime is limited by the source string storage. It keeps the length of the string, i.e. no need to call strlen() for various operations.

Header file

All zsview definitions and prototypes are available by including a single header file.

#include <stc/zsview.h>

Methods

zsview          c_zv(const char literal_only[]);                    // create from string literal only
zsview          zsview_from(const char* str);                       // construct from const char*
zsview          zsview_from_pos(zsview zv, isize_t pos);            // subview starting from index pos

isize_t         zsview_size(zsview zv);
bool            zsview_is_empty(zsview zv);                         // check if size == 0
void            zsview_clear(zsview* self);

csview          zsview_sv(zsview zv);                               // convert to csview type
csview          zsview_subview(zsview zv, isize_t pos, isize_t len); // return as csview span
zsview          zsview_tail(zsview zv, isize_t len);                 // subview of the trailing n bytes

bool            zsview_equals(zsview zv, const char* str);
isize_t         zsview_find(zsview zv, const char* str);
bool            zsview_contains(zsview zv, const char* str);
bool            zsview_starts_with(zsview zv, const char* str);
bool            zsview_ends_with(zsview zv, const char* str);

UTF8 methods

zsview          zsview_u8_from_pos(zsview zv, isize_t u8pos);       // subview starting from rune u8pos
isize_t         zsview_u8_size(zsview zv);                          // number of utf8 runes
zsview_iter     zsview_u8_at(zsview zv, isize_t u8pos);             // get rune at rune position
csview          zsview_u8_subview(zsview zs, isize_t u8pos, isize_t u8len);
zsview          zsview_u8_tail(zsview zv, isize_t u8len);           // subview of the last u8len runes
bool            zsview_u8_valid(zsview zv);                         // check utf8 validity of zv

bool            zsview_iequals(zsview zs, const char* str);         // utf8 case-insensitive comparison
bool            zsview_istarts_with(zsview zs, const char* str);    // utf8 case-insensitive
bool            zsview_iends_with(zsview zs, const char* str);      // utf8 case-insensitive

zsview_iter     zsview_begin(const zsview* self);                   // utf8 iteration
zsview_iter     zsview_end(const zsview* self);
void            zsview_next(zsview_iter* it);                       // next rune
zsview_iter     zsview_advance(zsview_iter it, isize_t u8pos);      // advance +/- runes
uint32_t        zsview_codepoint(const zsview_iter* it);            // return cached codepoint for iter

Helper methods for usage in containers

size_t          zsview_hash(const zsview* x);
int             zsview_cmp(const zsview* x, const zsview* y);
bool            zsview_eq(const zsview* x, const zsview* y);
int             zsview_icmp(const zsview* s1, const zsview* s2);    // utf8 case-insensitive comparison
bool            zsview_ieq(const zsview* s1, const zsview* s2);     // "

Types

Type name	Type definition	Used to represent...
zsview	struct { const char *str; isize_t size; }	The string view type
zsview_value	const char	The element type
zsview_iter	union { zsview_value *ref; csview chr; }	UTF8 iterator

Example: UTF8 iteration and case conversion

#include <stc/cstr.h>
#include <stc/zsview.h>

int main(void)
{
    zsview say = c_zv("Liberté, égalité, fraternité.");
    printf("%s\n", zs.str);

    for (c_each(i, zsview, say))
        printf(c_svfmt " ", c_svarg(i.chr));
    puts("");

    cstr upper = cstr_toupper_sv(zsview_sv(say));
    printf("%s\n", cstr_str(&upper));
    cstr_drop(&upper);
}

Output:

Liberté, égalité, fraternité.
L i b e r t é ,   é g a l i t é ,   f r a t e r n i t é .
LIBERTÉ, ÉGALITÉ, FRATERNITÉ.