#include "fitz-internal.h"

fz_buffer *
fz_new_buffer(fz_context *ctx, int size)
{
	fz_buffer *b;

	size = size > 1 ? size : 16;

	b = fz_malloc_struct(ctx, fz_buffer);
	b->refs = 1;
	fz_try(ctx)
	{
		b->data = fz_malloc(ctx, size);
	}
	fz_catch(ctx)
	{
		fz_free(ctx, b);
		fz_rethrow(ctx);
	}
	b->cap = size;
	b->len = 0;

	return b;
}

fz_buffer *
fz_keep_buffer(fz_context *ctx, fz_buffer *buf)
{
	if (buf)
	{
		if (buf->refs == 1 && buf->cap > buf->len+1)
			fz_resize_buffer(ctx, buf, buf->len);
		buf->refs ++;
	}

	return buf;
}

void
fz_drop_buffer(fz_context *ctx, fz_buffer *buf)
{
	if (!buf)
		return;
	if (--buf->refs == 0)
	{
		fz_free(ctx, buf->data);
		fz_free(ctx, buf);
	}
}

void
fz_resize_buffer(fz_context *ctx, fz_buffer *buf, int size)
{
	buf->data = fz_resize_array(ctx, buf->data, size, 1);
	buf->cap = size;
	if (buf->len > buf->cap)
		buf->len = buf->cap;
}

void
fz_grow_buffer(fz_context *ctx, fz_buffer *buf)
{
	fz_resize_buffer(ctx, buf, (buf->cap * 3) / 2);
}

void
fz_trim_buffer(fz_context *ctx, fz_buffer *buf)
{
	if (buf->cap > buf->len+1)
		fz_resize_buffer(ctx, buf, buf->len);
}

int
fz_buffer_storage(fz_context *ctx, fz_buffer *buf, unsigned char **datap)
{
	if (datap)
		*datap = (buf ? buf->data : NULL);
	return (buf ? buf->len : 0);
}

void
fz_buffer_printf(fz_context *ctx, fz_buffer *buffer, char *fmt, ...)
{
	int count;
	int done = 0;
	va_list args;
	va_start(args, fmt);

	while(!done)
	{
		count = vsnprintf(buffer->data + buffer->len, buffer->cap - buffer->len, fmt, args);
		done = (count >= 0 && count < buffer->cap - buffer->len);
		if (!done)
			fz_grow_buffer(ctx, buffer);
	}

	buffer->len += count;
	va_end(args);
}