9. Buffer Management

All content must be written to in-memory location. This is handled in a very simple way via a buffer type called wws_buffer.

typedef struct wws_buffer wws_buffer;

A wws_buffer struct contains the buffer itself (an unsigned char array), the current position of the buffer (which is therefore the current size), and the total size.

struct wws_buffer {
    int pos;
    int size;
    unsigned char *buf;
};

The wws_buffer is allocated with the function wws_buffer_alloc. Choose a largish size because this is the maximum HTML size for a page. Re-allocation could come later, but for this proof-of concept, a fixed size is simple and good enough.

void wws_buffer_alloc(wws_buffer *wb, int size);

void wws_buffer_alloc(wws_buffer *wb, int size)
{
    wb->buf = calloc(1, size);
    wb->pos = 0;
    wb->size = size;
}

A allocated buffer must be freed with wws_buffer_free.

void wws_buffer_free(wws_buffer *wb);

void wws_buffer_free(wws_buffer *wb)
{
    wb->size = 0;
    wb->pos = 0;
    free(wb->buf);
}

Write to the buffer using wws_buffer_write.

void wws_buffer_write(wws_buffer *wb,
                      const char *buf,
                      int size);

This copies over a chunk of data to the internal buffer. If the buffer is full, it just stops adding and breaks away.

void wws_buffer_write(wws_buffer *wb,
                      const char *buf,
                      int size)
{
    int i;
    if (wb->pos >= wb->size) {
       wws_buffer_extend(wb, 512);
    }
    for (i = 0; i < size; i++) {
        wb->buf[wb->pos] = buf[i];
        wb->pos++;
        if (wb->pos >= wb->size) {
            wws_buffer_extend(wb, 512);
        }
    }
}

Extending a buffer is done via wws_buffer_extend. This is done automatically inside of wws_buffer_write.

void wws_buffer_extend(wws_buffer *wb, int amount);

void wws_buffer_extend(wws_buffer *wb, int amount)
{
     wb->size += amount;
     wb->buf = realloc(wb->buf, wb->size);
}

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