str: New function ds_steal_cstr.

[pspp-builds.git] / src / libpspp / str.c

diff --git a/src/libpspp/str.c b/src/libpspp/str.c
index 3cff0492c7d508d99d9ce0b5c77c57879bc1faf7..79f3c912e9b649cf39d3ab9a0b37510e25867bf5 100644 (file)
--- a/src/libpspp/str.c
+++ b/src/libpspp/str.c
@@ -23,6 +23,7 @@
 #include <stdint.h>
 #include <stdlib.h>
 
+#include <libpspp/cast.h>
 #include <libpspp/message.h>
 #include <libpspp/pool.h>
 
@@ -125,9 +126,9 @@ str_compare_rpad (const char *a, const char *b)
 
 /* Copies string SRC to buffer DST, of size DST_SIZE bytes.
    DST is truncated to DST_SIZE bytes or padded on the right with
-   spaces as needed. */
+   copies of PAD as needed. */
 void
-buf_copy_str_rpad (char *dst, size_t dst_size, const char *src)
+buf_copy_str_rpad (char *dst, size_t dst_size, const char *src, char pad)
 {
   size_t src_len = strlen (src);
   if (src_len >= dst_size)
@@ -135,15 +136,15 @@ buf_copy_str_rpad (char *dst, size_t dst_size, const char *src)
   else
     {
       memcpy (dst, src, src_len);
-      memset (&dst[src_len], ' ', dst_size - src_len);
+      memset (&dst[src_len], pad, dst_size - src_len);
     }
 }
 
 /* Copies string SRC to buffer DST, of size DST_SIZE bytes.
    DST is truncated to DST_SIZE bytes or padded on the left with
-   spaces as needed. */
+   copies of PAD as needed. */
 void
-buf_copy_str_lpad (char *dst, size_t dst_size, const char *src)
+buf_copy_str_lpad (char *dst, size_t dst_size, const char *src, char pad)
 {
   size_t src_len = strlen (src);
   if (src_len >= dst_size)
@@ -151,40 +152,42 @@ buf_copy_str_lpad (char *dst, size_t dst_size, const char *src)
   else
     {
       size_t pad_cnt = dst_size - src_len;
-      memset (&dst[0], ' ', pad_cnt);
+      memset (&dst[0], pad, pad_cnt);
       memcpy (dst + pad_cnt, src, src_len);
     }
 }
 
 /* Copies buffer SRC, of SRC_SIZE bytes, to DST, of DST_SIZE bytes.
    DST is truncated to DST_SIZE bytes or padded on the left with
-   spaces as needed. */
+   copies of PAD as needed. */
 void
 buf_copy_lpad (char *dst, size_t dst_size,
-               const char *src, size_t src_size)
+               const char *src, size_t src_size,
+               char pad)
 {
   if (src_size >= dst_size)
     memmove (dst, src, dst_size);
   else
     {
-      memset (dst, ' ', dst_size - src_size);
+      memset (dst, pad, dst_size - src_size);
       memmove (&dst[dst_size - src_size], src, src_size);
     }
 }
 
 /* Copies buffer SRC, of SRC_SIZE bytes, to DST, of DST_SIZE bytes.
    DST is truncated to DST_SIZE bytes or padded on the right with
-   spaces as needed. */
+   copies of PAD as needed. */
 void
 buf_copy_rpad (char *dst, size_t dst_size,
-               const char *src, size_t src_size)
+               const char *src, size_t src_size,
+               char pad)
 {
   if (src_size >= dst_size)
     memmove (dst, src, dst_size);
   else
     {
       memmove (dst, src, src_size);
-      memset (&dst[src_size], ' ', dst_size - src_size);
+      memset (&dst[src_size], pad, dst_size - src_size);
     }
 }
 
@@ -1069,6 +1072,34 @@ ds_set_length (struct string *st, size_t new_length, char pad)
     st->ss.length = new_length;
 }
 
+/* Removes N characters from ST starting at offset START. */
+void
+ds_remove (struct string *st, size_t start, size_t n)
+{
+  if (n > 0 && start < st->ss.length)
+    {
+      if (st->ss.length - start <= n)
+        {
+          /* All characters at or beyond START are deleted. */
+          st->ss.length = start;
+        }
+      else
+        {
+          /* Some characters remain and must be shifted into
+             position. */
+          memmove (st->ss.string + st->ss.length,
+                   st->ss.string + st->ss.length + n,
+                   st->ss.length - start - n);
+          st->ss.length -= n;
+        }
+    }
+  else
+    {
+      /* There are no characters to delete or no characters at or
+         beyond START, hence deletion is a no-op. */
+    }
+}
+
 /* Returns true if ST is empty, false otherwise. */
 bool
 ds_is_empty (const struct string *st)
@@ -1184,13 +1215,24 @@ ds_capacity (const struct string *st)
 char *
 ds_cstr (const struct string *st_)
 {
-  struct string *st = (struct string *) st_;
+  struct string *st = CONST_CAST (struct string *, st_);
   if (st->ss.string == NULL)
     ds_extend (st, 1);
   st->ss.string[st->ss.length] = '\0';
   return st->ss.string;
 }
 
+/* Returns the value of ST as a null-terminated string and then
+   reinitialized ST as an empty string.  The caller must free the
+   returned string with free(). */
+char *
+ds_steal_cstr (struct string *st)
+{
+  char *s = ds_cstr (st);
+  ds_init_empty (st);
+  return s;
+}
+
 /* Reads characters from STREAM and appends them to ST, stopping
    after MAX_LENGTH characters, after appending a newline, or
    after an I/O error or end of file was encountered, whichever
@@ -1411,3 +1453,25 @@ ds_relocate (struct string *st)
       free ((char *) rel);
     }
 }
+
+
+\f
+
+/* Operations on uint8_t "strings" */
+
+/* Copies buffer SRC, of SRC_SIZE bytes, to DST, of DST_SIZE bytes.
+   DST is truncated to DST_SIZE bytes or padded on the right with
+   copies of PAD as needed. */
+void
+u8_buf_copy_rpad (uint8_t *dst, size_t dst_size,
+                 const uint8_t *src, size_t src_size,
+                 char pad)
+{
+  if (src_size >= dst_size)
+    memmove (dst, src, dst_size);
+  else
+    {
+      memmove (dst, src, src_size);
+      memset (&dst[src_size], pad, dst_size - src_size);
+    }
+}