add fmt_html_tagarg, fmt_xml

CHANGES

@@ -16,6 +16,7 @@
   switch epoll from level triggering to edge triggering
   introduce io_eagain_read and io_eagain_write (discontinue using io_eagain plz)
   fix buffer_get
+  add fmt_html_tagarg, fmt_xml
 
 0.29:
   save 8 bytes in taia.h for 64-bit systems

textcode.h

@@ -27,8 +27,15 @@ size_t fmt_urlencoded2(char* dest,const char* src,size_t len,const char* escapem
 size_t fmt_yenc(char* dest,const char* src,size_t len);
 /* Needs len*2 bytes */
 size_t fmt_hexdump(char* dest,const char* src,size_t len);
-/* Change '<' to '&lt;' and '&' to '&amp;'; worst case: len*5 */
+/* Change '<' to '&lt;' and '&' to '&amp;' and '\n' to '<br>'; worst case: len*5 */
+/* This is meant for outputting text that goes between tags */
 size_t fmt_html(char* dest,const char* src,size_t len);
+/* Change '<' to '&lt;' and '&' to '&amp;' and '"' to '&quot;'; worst case: len*6 */
+/* This is meant for outputting text that goes in a tag argument between double quotes*/
+size_t fmt_html_tagarg(char* dest,const char* src,size_t len);
+/* Change '<' to '&lt;' and '&' to '&amp;'; worst case: len*5 */
+size_t fmt_xml(char* dest,const char* src,size_t len);
+
 /* Change '\' to "\\", '\n' to "\n", ^A to "\x01" etc; worst case: len*4 */
 size_t fmt_cescape(char* dest,const char* src,size_t len);
 /* Worst case: len*4 */

textcode/fmt_html_tagarg.c

@@ -0,0 +1,26 @@
+#include "fmt.h"
+#include "textcode.h"
+#include "str.h"
+#include "haveinline.h"
+
+size_t fmt_html_tagarg(char* dest,const char* src,size_t len) {
+  register const unsigned char* s=(const unsigned char*) src;
+  size_t written=0,i;
+  const char* seq;
+  for (i=0; i<len; ++i) {
+    switch (s[i]) {
+    case '&': seq="&amp;"; goto doit;
+    case '<': seq="&lt;"; goto doit;
+    case '>': seq="&gt;"; goto doit;
+    case '"':
+	seq="&dquot;";
+      doit:
+	written+=fmt_str(dest?dest+written:0,seq);
+	break;
+    default: if (dest) dest[written]=s[i]; ++written; break;
+    }
+    /* in case someone gives us malicious input */
+    if (written>((size_t)-1)/2) return (size_t)-1;
+  }
+  return written;
+}

textcode/fmt_xml.c

@@ -0,0 +1,23 @@
+#include "fmt.h"
+#include "textcode.h"
+#include "str.h"
+#include "haveinline.h"
+
+size_t fmt_xml(char* dest,const char* src,size_t len) {
+  register const unsigned char* s=(const unsigned char*) src;
+  size_t written=0,i;
+  const char* seq;
+  for (i=0; i<len; ++i) {
+    switch (s[i]) {
+    case '&': seq="&amp;"; goto doit;
+    case '<': seq="&lt;";
+      doit:
+	written+=fmt_str(dest?dest+written:0,seq);
+	break;
+    default: if (dest) dest[written]=s[i]; ++written; break;
+    }
+    /* in case someone gives us malicious input */
+    if (written>((size_t)-1)/2) return (size_t)-1;
+  }
+  return written;
+}