Move source files to src/

1 files changed, 97 insertions, 0 deletions

diff --git a/src/jv_unicode.c b/src/jv_unicode.c
new file mode 100644
index 00000000..fbf7454b
--- /dev/null
+++ b/src/jv_unicode.c
@@ -0,0 +1,97 @@
+#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_ret) {
+  assert(in <= end);
+  if (in == end) {
+    return 0;
+  }
+  int codepoint = -1;
+  unsigned char first = (unsigned char)in[0];
+  int length = utf8_coding_length[first];
+  if ((first & 0x80) == 0) {
+    /* Fast-path for ASCII */
+    codepoint = first;
+    length = 1;
+  } else if (length == 0 || length == UTF8_CONTINUATION_BYTE) {
+    /* Bad single byte - either an invalid byte or an out-of-place continuation byte */
+    length = 1;
+  } else if (in + length > end) {
+    /* String ends before UTF8 sequence ends */
+    length = end - in;
+  } else {
+    codepoint = ((unsigned)in[0]) & utf8_coding_bits[first];
+    for (int i=1; i<length; i++) {
+      unsigned ch = (unsigned char)in[i];
+      if (utf8_coding_length[ch] != UTF8_CONTINUATION_BYTE){
+        /* Invalid UTF8 sequence - not followed by the right number of continuation bytes */
+        codepoint = -1;
+        length = i;
+        break;
+      }
+      codepoint = (codepoint << 6) | (ch & 0x3f);
+    }
+    if (codepoint < utf8_first_codepoint[length]) {
+      /* Overlong UTF8 sequence */
+      codepoint = -1;
+    }
+    if (0xD800 <= codepoint && codepoint <= 0xDFFF) {
+      /* Surrogate codepoints can't be encoded in UTF8 */
+      codepoint = -1;
+    }
+    if (codepoint > 0x10FFFF) {
+      /* Outside Unicode range */
+      codepoint = -1;
+    }
+  }
+  assert(length > 0);
+  *codepoint_ret = codepoint;
+  return in + length;
+}
+
+int jvp_utf8_is_valid(const char* in, const char* end) {
+  int codepoint;
+  while ((in = jvp_utf8_next(in, end, &codepoint))) {
+    if (codepoint == -1) return 0;
+  }
+  return 1;
+}
+
+/* Assumes startchar is the first byte of a valid character sequence */
+int jvp_utf8_decode_length(char startchar) {
+	if ((startchar & 0x80) == 0) return 1;         // 0___ ____
+	else if ((startchar & 0xE0) == 0xC0) return 2; // 110_ ____
+	else if ((startchar & 0xF0) == 0xE0) return 3; // 1110 ____
+	else return 4;                                 // 1111 ____
+}
+
+int jvp_utf8_encode_length(int codepoint) {
+  if (codepoint <= 0x7F) return 1;
+  else if (codepoint <= 0x7FF) return 2;
+  else if (codepoint <= 0xFFFF) return 3;
+  else return 4;
+}
+
+int jvp_utf8_encode(int codepoint, char* out) {
+  assert(codepoint >= 0 && codepoint <= 0x10FFFF);
+  char* start = out;
+  if (codepoint <= 0x7F) {
+    *out++ = codepoint;
+  } else if (codepoint <= 0x7FF) {
+    *out++ = 0xC0 + ((codepoint & 0x7C0) >> 6);
+    *out++ = 0x80 + ((codepoint & 0x03F));
+  } else if(codepoint <= 0xFFFF) {
+    *out++ = 0xE0 + ((codepoint & 0xF000) >> 12);
+    *out++ = 0x80 + ((codepoint & 0x0FC0) >> 6);
+    *out++ = 0x80 + ((codepoint & 0x003F));
+  } else {
+    *out++ = 0xF0 + ((codepoint & 0x1C0000) >> 18);
+    *out++ = 0x80 + ((codepoint & 0x03F000) >> 12);
+    *out++ = 0x80 + ((codepoint & 0x000FC0) >> 6);
+    *out++ = 0x80 + ((codepoint & 0x00003F));
+  }
+  assert(out - start == jvp_utf8_encode_length(codepoint));
+  return out - start;
+}