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-rw-r--r--src/commonmark.c336
1 files changed, 336 insertions, 0 deletions
diff --git a/src/commonmark.c b/src/commonmark.c
new file mode 100644
index 0000000..6c0de88
--- /dev/null
+++ b/src/commonmark.c
@@ -0,0 +1,336 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <ctype.h>
+
+#include "config.h"
+#include "cmark.h"
+#include "node.h"
+#include "buffer.h"
+#include "utf8.h"
+
+// Functions to convert cmark_nodes to commonmark strings.
+
+struct render_state {
+ cmark_strbuf* buffer;
+ cmark_strbuf* prefix;
+ int column;
+ int width;
+ int need_cr;
+ int last_breakable;
+ bool begin_line;
+};
+
+static inline void cr(struct render_state *state)
+{
+ if (state->need_cr < 1) {
+ state->need_cr = 1;
+ }
+}
+
+static inline void blankline(struct render_state *state)
+{
+ if (state->need_cr < 2) {
+ state->need_cr = 2;
+ }
+}
+
+static inline bool needs_escaping(int32_t c, unsigned char d)
+{
+ // TODO escape potential list markers at beginning of line
+ // (add param)
+ return (c == '*' || c == '_' || c == '[' || c == ']' ||
+ c == '<' || c == '>' || c == '\\' ||
+ (c == '&' && isalpha(d)) ||
+ (c == '!' && d == '['));
+}
+
+static inline void out(struct render_state *state,
+ cmark_chunk str,
+ bool wrap,
+ bool escape)
+{
+ unsigned char* source = str.data;
+ int length = str.len;
+ unsigned char nextc;
+ int32_t c;
+ int i = 0;
+ int len;
+ cmark_chunk remainder = cmark_chunk_literal("");
+ int k = state->buffer->size - 1;
+
+ while (state->need_cr) {
+ if (k < 0 || state->buffer->ptr[k] == '\n') {
+ k -= 1;
+ } else {
+ cmark_strbuf_putc(state->buffer, '\n');
+ if (state->need_cr > 1) {
+ cmark_strbuf_put(state->buffer, state->prefix->ptr,
+ state->prefix->size);
+ }
+ }
+ state->column = 0;
+ state->begin_line = true;
+ state->need_cr -= 1;
+ }
+
+ while (i < length) {
+ if (state->begin_line) {
+ cmark_strbuf_put(state->buffer, state->prefix->ptr,
+ state->prefix->size);
+ // note: this assumes prefix is ascii:
+ state->column = state->prefix->size;
+ }
+
+ len = utf8proc_iterate(source + i, length - i, &c);
+ nextc = source[i + len];
+ if (c == 32 && wrap) {
+ if (!state->begin_line) {
+ cmark_strbuf_putc(state->buffer, ' ');
+ state->column += 1;
+ state->begin_line = false;
+ state->last_breakable = state->buffer->size -
+ 1;
+ // skip following spaces
+ while (source[i + 1] == ' ') {
+ i++;
+ }
+ }
+
+ } else if (c == 10) {
+ cmark_strbuf_putc(state->buffer, '\n');
+ state->column = 0;
+ state->begin_line = true;
+ state->last_breakable = 0;
+ } else if (escape && needs_escaping(c, nextc)) {
+ cmark_strbuf_putc(state->buffer, '\\');
+ utf8proc_encode_char(c, state->buffer);
+ state->column += 2;
+ state->begin_line = false;
+ } else {
+ utf8proc_encode_char(c, state->buffer);
+ state->column += 1;
+ state->begin_line = false;
+ }
+
+ // If adding the character went beyond width, look for an
+ // earlier place where the line could be broken:
+ if (state->width > 0 &&
+ state->column > state->width &&
+ !state->begin_line &&
+ state->last_breakable > 0) {
+
+ // copy from last_breakable to remainder
+ cmark_chunk_set_cstr(&remainder, (char *) state->buffer->ptr + state->last_breakable + 1);
+ // truncate at last_breakable
+ cmark_strbuf_truncate(state->buffer, state->last_breakable);
+ // add newline, prefix, and remainder
+ cmark_strbuf_putc(state->buffer, '\n');
+ cmark_strbuf_put(state->buffer, state->prefix->ptr,
+ state->prefix->size);
+ cmark_strbuf_put(state->buffer, remainder.data, remainder.len);
+ state->column = state->prefix->size + remainder.len;
+ cmark_chunk_free(&remainder);
+ state->last_breakable = 0;
+ state->begin_line = false;
+ }
+
+ i += len;
+ }
+}
+
+static void lit(struct render_state *state, char *s, bool wrap)
+{
+ cmark_chunk str = cmark_chunk_literal(s);
+ out(state, str, wrap, false);
+}
+
+
+static int
+S_render_node(cmark_node *node, cmark_event_type ev_type,
+ struct render_state *state)
+{
+ cmark_node *tmp;
+ int list_number;
+ bool entering = (ev_type == CMARK_EVENT_ENTER);
+
+ switch (node->type) {
+ case CMARK_NODE_DOCUMENT:
+ if (!entering) {
+ cmark_strbuf_putc(state->buffer, '\n');
+ }
+ break;
+
+ case CMARK_NODE_BLOCK_QUOTE:
+ if (entering) {
+ lit(state, "> ", false);
+ cmark_strbuf_puts(state->prefix, "> ");
+ } else {
+ cmark_strbuf_truncate(state->prefix, state->prefix->size - 2);
+ blankline(state);
+ }
+ break;
+
+ case CMARK_NODE_LIST:
+ break;
+
+ case CMARK_NODE_ITEM:
+ if (entering) {
+ if (cmark_node_get_list_type(node->parent) ==
+ CMARK_BULLET_LIST) {
+ lit(state, "- ", false);
+ cmark_strbuf_puts(state->prefix, " ");
+ } else {
+ list_number = cmark_node_get_list_start(node->parent);
+ tmp = node;
+ while (tmp->prev) {
+ tmp = tmp->prev;
+ list_number += 1;
+ }
+ lit(state, "1. ", false);
+ cmark_strbuf_puts(state->prefix, " ");
+ }
+ } else {
+ cmark_strbuf_truncate(state->prefix, state->prefix->size -
+ (cmark_node_get_list_type(node->parent) ==
+ CMARK_BULLET_LIST ? 2 : 4));
+ cr(state);
+ }
+ break;
+
+ case CMARK_NODE_HEADER:
+ if (entering) {
+ for (int i = cmark_node_get_header_level(node); i > 0; i--) {
+ lit(state, "#", false);
+ }
+ lit(state, " ", false);
+ // TODO set a "nowrap" variable in state, and refer to this in out()
+ } else {
+ blankline(state);
+ }
+ break;
+
+ case CMARK_NODE_CODE_BLOCK:
+ blankline(state);
+ // TODO variable number of ticks
+ lit(state, "```", false);
+ cr(state);
+ // TODO info string
+ // TODO use indented form if no info string?
+ out(state, node->as.code.literal, false, true);
+ cr(state);
+ lit(state, "```", false);
+ blankline(state);
+ break;
+
+ case CMARK_NODE_HTML:
+ blankline(state);
+ out(state, node->as.code.literal, false, false);
+ blankline(state);
+ break;
+
+ case CMARK_NODE_HRULE:
+ blankline(state);
+ lit(state, "-----", false);
+ blankline(state);
+ break;
+
+ case CMARK_NODE_PARAGRAPH:
+ if (!entering) {
+ blankline(state);
+ }
+ break;
+
+ case CMARK_NODE_TEXT:
+ out(state, node->as.literal, true, true);
+ break;
+
+ case CMARK_NODE_LINEBREAK:
+ lit(state, "\\", false);
+ cr(state);
+ break;
+
+ case CMARK_NODE_SOFTBREAK:
+ lit(state, " ", true);
+ break;
+
+ case CMARK_NODE_CODE:
+ // TODO variable number of ticks
+ lit(state, "`", false);
+ out(state, node->as.literal, true, false);
+ lit(state, "`", false);
+ break;
+
+ case CMARK_NODE_INLINE_HTML:
+ out(state, node->as.literal, true, false);
+ break;
+
+ case CMARK_NODE_STRONG:
+ if (entering) {
+ lit(state, "**", false);
+ } else {
+ lit(state, "**", false);
+ }
+ break;
+
+ case CMARK_NODE_EMPH:
+ if (entering) {
+ lit(state, "*", false);
+ } else {
+ lit(state, "*", false);
+ }
+ break;
+
+ case CMARK_NODE_LINK:
+ if (entering) {
+ lit(state, "[", false);
+ } else {
+ lit(state, "](", false);
+ out(state, cmark_chunk_literal(cmark_node_get_url(node)), false, true);
+ // TODO title
+ lit(state, ")", false);
+ }
+ break;
+
+ case CMARK_NODE_IMAGE:
+ if (entering) {
+ lit(state, "![", false);
+ } else {
+ lit(state, "](", false);
+ out(state, cmark_chunk_literal(cmark_node_get_url(node)), false, true);
+ // TODO title
+ lit(state, ")", false);
+ }
+ break;
+
+ default:
+ assert(false);
+ break;
+ }
+
+ return 1;
+}
+
+char *cmark_render_commonmark(cmark_node *root, int options)
+{
+ char *result;
+ cmark_strbuf commonmark = GH_BUF_INIT;
+ cmark_strbuf prefix = GH_BUF_INIT;
+ struct render_state state = { &commonmark, &prefix, 0, 65, 0, 0, true };
+ cmark_node *cur;
+ cmark_event_type ev_type;
+ cmark_iter *iter = cmark_iter_new(root);
+
+ if (options == 0) options = 0; // avoid warning about unused parameters
+
+ while ((ev_type = cmark_iter_next(iter)) != CMARK_EVENT_DONE) {
+ cur = cmark_iter_get_node(iter);
+ S_render_node(cur, ev_type, &state);
+ }
+ result = (char *)cmark_strbuf_detach(&commonmark);
+
+ cmark_strbuf_free(&prefix);
+ cmark_iter_free(iter);
+ return result;
+}