Replace pointer arithmetic in escape_and_add_tags with strcpy() and add documentation

1 files changed, 18 insertions, 10 deletions

diff --git a/src/gemini2html.c b/src/gemini2html.c
index bbc5788..827f1dc 100644
--- a/src/gemini2html.c
+++ b/src/gemini2html.c
@@ -90,28 +90,36 @@ void skip_non_whitespace(const char* str, size_t* pos) {
     while (str[*pos] != '\0' && !(str[*pos] == ' ' || str[*pos] == '\t')) (*pos)++;
 }
 
-char* escape_and_add_tags(const char* opening_tag, const char* unescaped, const char* closing_tag, const size_t unescaped_size, const bool add_newline) {
+char* escape_and_add_tags(const char* opening_tag, const char* unescaped, const char* closing_tag, const size_t unescaped_size, const bool append_newline) {
     char* escaped = escape_text(unescaped, unescaped_size);
 
+    size_t opening_tag_len = strlen(opening_tag);
     size_t escaped_len = strlen(escaped);
-    char* escaped_with_tags = malloc(strlen(opening_tag) + escaped_len + strlen(closing_tag) + 1);
+    size_t closing_tag_len = strlen(closing_tag);
+
+    char* escaped_with_tags = malloc(opening_tag_len + escaped_len + closing_tag_len + 1);
     size_t index = 0;
 
-    // write opening tag
-    for (size_t i = 0; i < strlen(opening_tag); i++) escaped_with_tags[index++] = opening_tag[i];
+    /* append opening tag */
+    strncpy(escaped_with_tags + index, opening_tag, opening_tag_len);
+    index += opening_tag_len;
 
-    // write innerText
-    for (size_t i = 0; i < escaped_len - 1; i++) escaped_with_tags[index++] = escaped[i];
+    /* append escaped text without newline at the end, if one exists */
+    strncpy(escaped_with_tags + index, escaped, escaped_len - 1);
+    index += escaped_len - 1;
     bool is_newline = escaped[escaped_len - 1] == '\n';
     if (!is_newline) escaped_with_tags[index++] = escaped[escaped_len - 1];
 
-    // free escaped HTML memory
+    /* escaped string is no longer needed, so free it */
     free(escaped);
     escaped = NULL;
 
-    // write closing tag
-    for (size_t i = 0; i < strlen(closing_tag); i++) escaped_with_tags[index++] = closing_tag[i];
-    if (add_newline) escaped_with_tags[index++] = '\n';
+    /* append closing tag */
+    strncpy(escaped_with_tags + index, closing_tag, closing_tag_len);
+    index += closing_tag_len;
+
+    /* append newline if caller wants one */
+    if (append_newline) escaped_with_tags[index++] = '\n';
     escaped_with_tags[index] = '\0';
 
     return escaped_with_tags;