diff src/c/urweb.c @ 829:20fe00fd81da

Substring functions; fix a nasty MonoReduce pattern match substitution bug
author Adam Chlipala <adamc@hcoop.net>
date Sat, 30 May 2009 13:29:00 -0400
parents 14a6c0971d89
children 5e1a4b12c83a
line wrap: on
line diff
--- a/src/c/urweb.c	Sat May 30 09:59:10 2009 -0400
+++ b/src/c/urweb.c	Sat May 30 13:29:00 2009 -0400
@@ -1811,6 +1811,21 @@
   return strlen(s);
 }
 
+uw_Basis_string uw_Basis_strchr(uw_context ctx, uw_Basis_string s, uw_Basis_char ch) {
+  return strchr(s, ch);
+}
+
+uw_Basis_int *uw_Basis_strindex(uw_context ctx, uw_Basis_string s, uw_Basis_char ch) {
+  uw_Basis_string r = strchr(s, ch);
+  if (r == NULL)
+    return NULL;
+  else {
+    uw_Basis_int *nr = uw_malloc(ctx, sizeof(uw_Basis_int));
+    *nr = r - s;
+    return nr;
+  }
+}
+
 uw_Basis_string uw_Basis_strcat(uw_context ctx, uw_Basis_string s1, uw_Basis_string s2) {
   int len = uw_Basis_strlen(ctx, s1) + uw_Basis_strlen(ctx, s2) + 1;
   char *s;
@@ -1826,6 +1841,27 @@
   return s;
 }
 
+uw_Basis_string uw_Basis_substring(uw_context ctx, uw_Basis_string s, uw_Basis_int start, uw_Basis_int len) {
+  size_t full_len = uw_Basis_strlen(ctx, s);
+
+  if (start < 0)
+    uw_error(ctx, FATAL, "substring: Negative start index");
+  if (len < 0)
+    uw_error(ctx, FATAL, "substring: Negative length");
+  if (start + len > full_len)
+    uw_error(ctx, FATAL, "substring: Start index plus length is too large");
+
+  if (start + len == full_len)
+    return &s[start];
+  else {
+    uw_Basis_string r = uw_malloc(ctx, len+1);
+    memcpy(r, s, len);
+    r[len] = 0;
+    return r;
+  }
+    
+}
+
 uw_Basis_string uw_strdup(uw_context ctx, uw_Basis_string s1) {
   int len = uw_Basis_strlen(ctx, s1) + 1;
   char *s;