membuf.h

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#ifndef LELY_UTIL_MEMBUF_H_
#define LELY_UTIL_MEMBUF_H_
 
#include <lely/util/util.h>
 
#include <stddef.h>
#include <string.h>
 
#ifndef LELY_UTIL_MEMBUF_INLINE
#define LELY_UTIL_MEMBUF_INLINE static inline
#endif
 
struct membuf {
        char *cur;
        char *begin;
        char *end;
};
 
#define MEMBUF_INIT \
        { \
                NULL, NULL, NULL \
        }
 
#ifdef __cplusplus
extern "C" {
#endif
 
LELY_UTIL_MEMBUF_INLINE void membuf_init(struct membuf *buf);
 
void membuf_fini(struct membuf *buf);
 
LELY_UTIL_MEMBUF_INLINE void *membuf_begin(const struct membuf *buf);
 
LELY_UTIL_MEMBUF_INLINE void membuf_clear(struct membuf *buf);
 
LELY_UTIL_MEMBUF_INLINE size_t membuf_size(const struct membuf *buf);
 
LELY_UTIL_MEMBUF_INLINE size_t membuf_capacity(const struct membuf *buf);
 
size_t membuf_reserve(struct membuf *buf, size_t size);
 
LELY_UTIL_MEMBUF_INLINE ptrdiff_t membuf_seek(
                struct membuf *buf, ptrdiff_t offset);
 
LELY_UTIL_MEMBUF_INLINE void *membuf_alloc(struct membuf *buf, size_t *size);
 
LELY_UTIL_MEMBUF_INLINE size_t membuf_write(
                struct membuf *buf, const void *ptr, size_t size);
 
void membuf_flush(struct membuf *buf, size_t size);
 
inline void
membuf_init(struct membuf *buf)
{
        buf->begin = buf->end = buf->cur = NULL;
}
 
inline void *
membuf_begin(const struct membuf *buf)
{
        return buf->begin;
}
 
inline void
membuf_clear(struct membuf *buf)
{
        buf->cur = buf->begin;
}
 
inline size_t
membuf_size(const struct membuf *buf)
{
        return buf->cur - buf->begin;
}
 
inline size_t
membuf_capacity(const struct membuf *buf)
{
        return buf->end - buf->cur;
}
 
inline ptrdiff_t
membuf_seek(struct membuf *buf, ptrdiff_t offset)
{
        char *cur = buf->cur + offset;
        if (cur - buf->begin < 0) {
                cur = buf->begin;
                offset = cur - buf->cur;
        } else if (buf->end - cur < 0) {
                cur = buf->end;
                offset = cur - buf->cur;
        }
        buf->cur = cur;
 
        return offset;
}
 
inline void *
membuf_alloc(struct membuf *buf, size_t *size)
{
        void *cur = buf->cur;
        *size = membuf_seek(buf, *size);
        return cur;
}
 
inline size_t
membuf_write(struct membuf *buf, const void *ptr, size_t size)
{
        void *cur = membuf_alloc(buf, &size);
        memcpy(cur, ptr, size);
        return size;
}
 
#ifdef __cplusplus
}
#endif
 
#endif // !LELY_UTIL_MEMBUF_H_