From 0fd7d4b30cafbc9a1e4fecfafe21921e2923daaa Mon Sep 17 00:00:00 2001
From: Stephen Dolan <mu@netsoc.tcd.ie>
Date: Thu, 6 Sep 2012 21:36:11 +0100
Subject: [PATCH] UTF8 coding utilities and unicode escaping in jv_dump()'d
 strings.

Beyond the Basic Multilingual Plane, dead Cthulhu waits dreaming.
---
 c/Makefile           |  4 ++++
 c/gen_utf8_tables.py | 30 ++++++++++++++++++++++++++++++
 c/jv_print.c         | 30 ++++++++++++++++++++++++------
 c/jv_unicode.c       | 34 ++++++++++++++++++++++++++++++++++
 c/jv_unicode.h       |  4 ++++
 5 files changed, 96 insertions(+), 6 deletions(-)
 create mode 100644 c/gen_utf8_tables.py

diff --git a/c/Makefile b/c/Makefile
index 6496da8b..2c4379de 100644
--- a/c/Makefile
+++ b/c/Makefile
@@ -8,6 +8,8 @@ clean:
 	sed 's/.*`\(.*\)'\''.*/\1/' | grep -v '^all$$' | \
 	xargs rm
 
+jv_utf8_tables.h: gen_utf8_tables.py
+	python $^ > $@
 
 lexer.yy.c: lexer.l
 	flex -o lexer.yy.c --header-file=lexer.yy.h lexer.l
@@ -17,6 +19,8 @@ parser.tab.c: parser.y lexer.yy.h
 	bison -W -d parser.y -v --report-file=parser.info
 parser.tab.h: parser.tab.c
 
+jv_unicode.c: jv_utf8_tables.h
+
 parsertest: parser.tab.c lexer.yy.c main.c opcode.c bytecode.c compile.c execute.c builtin.c jv.c jv_parse.c jv_print.c jv_dtoa.c jv_unicode.c
 	$(CC) -o $@ $^
 
diff --git a/c/gen_utf8_tables.py b/c/gen_utf8_tables.py
new file mode 100644
index 00000000..9d8dc3c0
--- /dev/null
+++ b/c/gen_utf8_tables.py
@@ -0,0 +1,30 @@
+#!/usr/bin/python
+
+mask = lambda n: (1 << n) - 1
+
+
+def print_table(type, name, t):
+    assert len(t) == 256
+    print "const static",type, name+"[]", "="
+    first = True
+    for i in range(0,len(t),16):
+        print (" {" if i == 0 else "  ") +\
+            ", ".join("0x%02x"%n for n in t[i:i+16]) + \
+            ("," if i + 16 < 256 else "};")
+
+
+def utf8info(c):
+    if c < 0x80: return 1, mask(7)
+    if 0x80 <= c <= 0xBF: return 255, mask(6)
+    if 0xC0 <= c <= 0xC1: return 0, 0
+    if 0xC2 <= c <= 0xDF: return 2, mask(5)
+    if 0xE0 <= c <= 0xEF: return 3, mask(4)
+    if 0xF0 <= c <= 0xF4: return 4, mask(3)
+    if 0xF4 <= c <= 0xFF: return 0, 0
+        
+table = lambda i: [utf8info(c)[i] for c in range(256)]
+
+print "#define UTF8_CONTINUATION_BYTE ((unsigned char)255)"
+
+print_table("unsigned char", "utf8_coding_length", table(0))
+print_table("unsigned char", "utf8_coding_bits", table(1))
diff --git a/c/jv_print.c b/c/jv_print.c
index c082e935..c9808ea7 100644
--- a/c/jv_print.c
+++ b/c/jv_print.c
@@ -1,22 +1,25 @@
 #include "jv.h"
 #include <stdio.h>
+#include <float.h>
+#include <math.h>
 
 #include "jv_dtoa.h"
+#include "jv_unicode.h"
 
 static void jv_dump_string(jv str, int ascii_only) {
   assert(jv_get_kind(str) == JV_KIND_STRING);
   const char* i = jv_string_value(str);
-  const char* end = i + jv_string_length(str);
-  while (i < end) {
-    int unicode_escape;
-    int c = (unsigned char)*i++;
+  const char* end = i + jv_string_length(jv_copy(str));
+  int c;
+  while ((i = jvp_utf8_next(i, end, &c))) {
+    assert(c != -1);
+    int unicode_escape = 0;
     if (0x20 <= c && c <= 0x7E) {
       // printable ASCII
       if (c == '"' || c == '\\') {
         putchar('\\');
       }
       putchar(c);
-      unicode_escape = 0;
     } else if (c < 0x20 || c == 0x7F) {
       // ASCII control character
       switch (c) {
@@ -44,8 +47,21 @@ static void jv_dump_string(jv str, int ascii_only) {
         unicode_escape = 1;
         break;
       }
+    } else {
+      unicode_escape = 1;
+    }
+    if (unicode_escape) {
+      if (c <= 0xffff) {
+        printf("\\u%04x", c);
+      } else {
+        c -= 0x10000;
+        printf("\\u%04x\\u%04x", 
+               0xD800 | ((c & 0xffc00) >> 10),
+               0xDC00 | (c & 0x003ff));
+      }
     }
   }
+  assert(c != -1);
 }
 
 static void jv_dump_term(struct dtoa_context* C, jv x) {
@@ -65,7 +81,9 @@ static void jv_dump_term(struct dtoa_context* C, jv x) {
     break;
   case JV_KIND_STRING:
     // FIXME: all sorts of broken
-    printf("\"%s\"", jv_string_value(x));
+    putchar('"');
+    jv_dump_string(x, 0);
+    putchar('"');
     break;
   case JV_KIND_ARRAY: {
     printf("[");
diff --git a/c/jv_unicode.c b/c/jv_unicode.c
index b1475ff6..375ad367 100644
--- a/c/jv_unicode.c
+++ b/c/jv_unicode.c
@@ -1,5 +1,39 @@
+#include <stdio.h>
 #include <assert.h>
 #include "jv_unicode.h"
+#include "jv_utf8_tables.h"
+
+const char* jvp_utf8_next(const char* in, const char* end, int* codepoint) {
+  if (in == end) {
+    codepoint = 0;
+    return 0;
+  }
+  unsigned char first = (unsigned char)in[0];
+  int length = utf8_coding_length[first];
+  if (length == 0 || length == UTF8_CONTINUATION_BYTE || in + length > end) {
+    *codepoint = -1;
+    return 0;
+  }
+  *codepoint = ((unsigned)in[0]) & utf8_coding_bits[first];
+  for (int i=1; i<length; i++) {
+    int ch = (unsigned char)in[i];
+    if (utf8_coding_length[(unsigned char)in[i]] != UTF8_CONTINUATION_BYTE){
+      *codepoint = -1;
+      return 0;
+    }
+    *codepoint = (*codepoint << 6) | (ch & 0x3f);
+  }
+  return in + length;
+}
+
+int jvp_utf8_verify(const char* in, const char* end) {
+  int codepoint = 0;
+  while ((in = jvp_utf8_next(in, end, &codepoint))) {
+    if (codepoint == -1) return 0;
+  }
+  return codepoint != -1;
+}
+
 int jvp_utf8_encode_length(int codepoint) {
   if (codepoint <= 0x7F) return 1;
   else if (codepoint <= 0x7FF) return 2;
diff --git a/c/jv_unicode.h b/c/jv_unicode.h
index 041c29aa..78c7a40d 100644
--- a/c/jv_unicode.h
+++ b/c/jv_unicode.h
@@ -1,5 +1,9 @@
 #ifndef JV_UNICODE_H
 #define JV_UNICODE_H
+
+const char* jvp_utf8_next(const char* in, const char* end, int* codepoint);
+
+
 int jvp_utf8_decode_length(char startchar);
 
 int jvp_utf8_encode_length(int codepoint);