/* See LICENSE file for copyright and license details. */
#include "common.h"


int
feedbuffer(int fd, struct buffer *buffer, const char *fname)
{
	ssize_t r;
	if (buffer->offset == buffer->size)
		buffer->buf = erealloc(buffer->buf, buffer->size += 8192);
again:
	r = read(fd, &buffer->buf[buffer->offset], buffer->size - buffer->offset);
	if (r <= 0) {
		if (!r)
			return 1;
		if (errno == EINTR)
			goto again;
		weprintf("%s:", fname);
		return -1;
	}
	buffer->offset += (size_t)r;
	return 0;
}


void
shiftbuffer(struct algorithm *algorithms, size_t nalgorithms, struct buffer *buffer)
{
	size_t i, consumed = SIZE_MAX;
	for (i = 0; i < nalgorithms; i++)
		consumed = MIN(consumed, algorithms[i].offset);
	if (!consumed)
		return;
	for (i = 0; i < nalgorithms; i++)
		algorithms[i].offset -= consumed;
	memmove(&buffer->buf[0], &buffer->buf[consumed], buffer->ready -= consumed);
	memmove(&buffer->buf[buffer->ready], &buffer->buf[buffer->procoff], buffer->offset - buffer->procoff);
	buffer->offset -= buffer->procoff - buffer->ready;
	buffer->procoff = buffer->ready;
}


int
unhex(struct buffer *buffer)
{
	size_t i = buffer->procoff;
	char a, b;

	for (;;) {
		while (i < buffer->offset && isspace(buffer->buf[i]))
			i++;
		if (i == buffer->offset)
			break;

		buffer->procoff = i;
		if (!isxdigit(buffer->buf[i]))
			return -1;
		a = buffer->buf[i++];

		while (i < buffer->offset && isspace(buffer->buf[i]))
			i++;
		if (i == buffer->offset)
			break;

		if (!isxdigit(buffer->buf[i]))
			return -1;
		b = buffer->buf[i++];
		buffer->procoff = i;

		a = (char)((a & 15) + (a > '9' ? 9 : 0));
		b = (char)((b & 15) + (b > '9' ? 9 : 0));
		a <<= 4;
		a |= b;
		buffer->buf[buffer->ready++] = a;
	}

	return 0;
}