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


static size_t
hunk_head(const char *text, size_t len, size_t *first, size_t *count)
{
	size_t off = 1, r;
	off += r = libpatch_get_zu__(&text[off], len - off, first);
	if (!r)
		return 0;
	if (off < len && text[off] == ' ') {
		off += 1;
		off += r = libpatch_get_zu__(&text[off], len - off, count);
		if (!r)
			return 0;
	} else {
		*count = 1;
	}
	return off;
}


int
libpatch_parse_rcs_patch(const char *text, size_t textlen, size_t *textend,
                         struct libpatch_patch **patch, size_t *patchlen)
{
	const char *patchtext = text;
	size_t len = 0, size = 0, line, count = 0;
	int has_patch = 0;

	while ((len = libpatch_next_line__(&text, &textlen, len))) {
		if (count) {
			count -= 1;
			APPEND_STRING(0, LIBPATCH_PATCH_FILE2_ONLY);
			(*patch)[*patchlen - 1].file1_lineno = line;

		} else if (len >= 5 && !strncmp(text, "diff ", 5)) {
			if (has_patch && textend)
				break;
			APPEND_STRING(5, LIBPATCH_PATCH_DIFF_LINE);

		} else if (len >= 2 && text[0] == 'd' && isdigit(text[1])) {
			if (hunk_head(text, len, &line, &count) < len)
				goto garbage;
			APPEND_NO_TEXT(LIBPATCH_PATCH_HUNK_WITH_DELETION);
			(*patch)[*patchlen - 1].first_line = line;
			(*patch)[*patchlen - 1].line_count = count;
			has_patch = 1;

		} else if (len >= 2 && text[0] == 'a' && isdigit(text[1])) {
			if (hunk_head(text, len, &line, &count) < len)
				goto garbage;
			APPEND_NO_TEXT(LIBPATCH_PATCH_HUNK);
			line += 1;
			has_patch = 1;

		} else {
		garbage:
			APPEND_STRING(0, LIBPATCH_PATCH_GARBAGE);
			if (len == textlen)
				(*patch)[*patchlen - 1].lf_terminated = 0;
		}
	}

	if (textend)
		*textend = (size_t)(text - patchtext);

	return 0;

fail:
	free(*patch);
	*patch = NULL;
	*patchlen = 0;
	return -1;
}