add stralloc_diff and stralloc_diffs

CHANGES

@@ -4,6 +4,7 @@
   add buffer_putsa, buffer_get_token_sa and buffer_getline_sa
   extended uudecode test.  See comment at top for details.
   fix #include in ndelay*.3 (Hynek Schlawack)
+  add stralloc_diff and stralloc_diffs (my invention)
 
 0.14:
   avoid bus errors in byte_copy

stralloc.h

@@ -1,6 +1,13 @@
 #ifndef STRALLOC_H
 #define STRALLOC_H
 
+#ifdef __dietlibc__
+#include <sys/cdefs.h>
+#endif
+#ifndef __pure__
+#define __pure__
+#endif
+
 /* stralloc is the internal data structure all functions are working on.
  * s is the string.
  * len is the used length of the string.
@@ -66,7 +73,17 @@ extern int stralloc_append(stralloc* sa,const char* in); /* beware: this takes a
 /* stralloc_starts returns 1 if the \0-terminated string in "in", without
  * the terminating \0, is a prefix of the string stored in sa. Otherwise
  * it returns 0. sa must already be allocated. */
-extern int stralloc_starts(stralloc* sa,const char* in);
+extern int stralloc_starts(stralloc* sa,const char* in) __pure__;
+
+/* stralloc_diff returns negative, 0, or positive, depending on whether
+ * a is lexicographically smaller than, equal to, or greater than the
+ * string b. */
+extern int stralloc_diff(const stralloc* a,const stralloc* b) __pure__;
+
+/* stralloc_diffs returns negative, 0, or positive, depending on whether
+ * a is lexicographically smaller than, equal to, or greater than the
+ * string b[0], b[1], ..., b[n]=='\0'. */
+extern int stralloc_diffs(const stralloc* a,const char* b) __pure__;
 
 /* stralloc_0 appends \0 */
 #define stralloc_0(sa) stralloc_append(sa,"")

stralloc/stralloc_diff.3

@@ -0,0 +1,13 @@
+.TH stralloc_diffs 3
+.SH NAME
+stralloc_diffs \- compare two strallocs
+.SH SYNTAX
+.B #include <stralloc.h>
+
+int \fBstralloc_diff\fP(const stralloc* \fIa\fR,const stralloc* \fIb\fR);
+.SH DESCRIPTION
+stralloc_diff returns negative, 0, or positive, depending on whether
+\fIa\fR is lexicographically smaller than, equal to, or greater than the
+string \fIb\fR.
+.SH "SEE ALSO"
+stralloc_diffs(3), stralloc_starts(3)

stralloc/stralloc_diff.c

@@ -0,0 +1,14 @@
+#include "stralloc.h"
+#include "byte.h"
+#include "str.h"
+
+extern int stralloc_diff(const stralloc* a,const stralloc* b) {
+  register unsigned int i;
+  register int j;
+  for (i=0;;++i) {
+    if (i==a->len) return i==b->len?0:-1; if (i==b->len) return 1;
+    if ((j=(a->s[i]-b->s[i]))) return j;
+  }
+  return j;
+}
+

stralloc/stralloc_diffs.3

@@ -0,0 +1,14 @@
+.TH stralloc_diffs 3
+.SH NAME
+stralloc_diffs \- check if string is prefix of stralloc
+.SH SYNTAX
+.B #include <stralloc.h>
+
+int \fBstralloc_diffs\fP(stralloc* \fIa\fR,const char* \fIb\fR);
+.SH DESCRIPTION
+stralloc_diffs returns negative, 0, or positive, depending on whether
+the \\0-terminated string in \fIa\fR, without
+the terminating \\0, is lexicographically smaller than, equal to, or
+greater than the string stored in \fIa\fR.
+.SH "SEE ALSO"
+stralloc_diff(3), stralloc_starts(3), str_diff(3)

stralloc/stralloc_diffs.c

@@ -0,0 +1,14 @@
+#include "stralloc.h"
+#include "byte.h"
+#include "str.h"
+
+extern int stralloc_diffs(const stralloc* a,const char* b) {
+  register unsigned int i;
+  register int j;
+  for (i=0;;++i) {
+    if (i==a->len) return (!b[i])?0:-1; if (!b[i]) return 1;
+    if ((j=(a->s[i]-b[i]))) return j;
+  }
+  return j;
+}
+

stralloc/stralloc_starts.3

@@ -6,7 +6,7 @@ stralloc_starts \- check if string is prefix of stralloc
 
 int \fBstralloc_starts\fP(stralloc* \fIsa\fR,const char* \fIin\fR);
 .SH DESCRIPTION
-stralloc_starts returns 1 if the \\0-terminated string in \fIbuf\fR, without
+stralloc_starts returns 1 if the \\0-terminated string in \fIin\fR, without
 the terminating \\0, is a prefix of the string stored in \fIsa\fR. Otherwise
 it returns 0. \fIsa\fR must already be allocated.
 .SH "SEE ALSO"

t.c

@@ -22,8 +22,26 @@
      __asm__ __volatile__ ("rdtsc" : "=a" (low) : : "edx")
 
 int main(int argc,char* argv[]) {
+#if 0
+  static stralloc s,t;
+  stralloc_copys(&s,"fnord");
+  stralloc_copys(&t,"abc"); printf("%d\n",stralloc_diff(&s,&t));
+  stralloc_copys(&t,"fnor"); printf("%d\n",stralloc_diff(&s,&t));
+  stralloc_copys(&t,"fnord"); printf("%d\n",stralloc_diff(&s,&t));
+  stralloc_copys(&t,"fnordh"); printf("%d\n",stralloc_diff(&s,&t));
+  stralloc_copys(&t,"hausen"); printf("%d\n",stralloc_diff(&s,&t));
+#endif
+  static stralloc s;
+  stralloc_copys(&s,"fnord");
+  printf("%d\n",stralloc_diffs(&s,"abc"));
+  printf("%d\n",stralloc_diffs(&s,"fnor"));
+  printf("%d\n",stralloc_diffs(&s,"fnord"));
+  printf("%d\n",stralloc_diffs(&s,"fnordh"));
+  printf("%d\n",stralloc_diffs(&s,"hausen"));
+#if 0
   printf("%d\n",case_starts("fnordhausen","FnOrD"));
   printf("%d\n",case_starts("fnordhausen","blah"));
+#endif
 #if 0
   char buf[]="FnOrD";
   case_lowers(buf);