new facilities needed by recently committed Pnmconvol updates: string list option type, token parsing, file line I/O

git-svn-id: http://svn.code.sf.net/p/netpbm/code/trunk@1031 9d0c8265-081b-0410-96cb-a4ca84ce46f8

1 files changed, 79 insertions, 0 deletions

diff --git a/lib/util/token.c b/lib/util/token.c
new file mode 100644
index 00000000..c4fe0aed
--- /dev/null
+++ b/lib/util/token.c
@@ -0,0 +1,79 @@
+#include <stdlib.h>
+#include <assert.h>
+
+#include "nstring.h"
+
+#include "token.h"
+
+
+void
+pm_gettoken(const char *  const tokenStart,
+            char          const delimiter,
+            const char ** const tokenP,
+            const char ** const nextP,
+            const char ** const errorP) {
+/*----------------------------------------------------------------------------
+   Find the token starting at 'tokenStart' up to but not including
+   the first 'delimiter' character or end of string.  Return it in newly
+   malloced memory as *tokenP, NUL-terminated.
+
+   Make *nextP point just past the token, i.e. to the delimiter or
+   end of string NUL character.
+
+   Note that if the string is empty, or starts with the delimiter,
+   we return an empty string and *nextP == tokenStart, i.e. *nextP
+   doesn't necessarily advance.
+-----------------------------------------------------------------------------*/
+    char * token;
+    const char * cursor;
+    unsigned int charCount;
+
+    /* Run through the token, counting characters */
+
+    charCount = 0;        /* initial value */
+    cursor = tokenStart;  /* initial value */
+    *errorP = NULL;       /* initial value */
+
+    while (*cursor != delimiter && *cursor != '\0' && !*errorP) {
+        if (*cursor == '\\') {
+            ++cursor;
+            if (*cursor == '\0')
+                asprintfN(errorP, "string ends with an escape character (\\)");
+        } else {
+            ++cursor;
+            ++charCount;
+        }
+    }
+    if (!*errorP) {
+        token = malloc(charCount + 1);
+        if (token == NULL)
+            asprintfN(errorP, "Could not allocate %u bytes of memory "
+                      "to parse a string",
+                      charCount + 1);
+        else {
+            /* Go back and do it again, this time copying the characters */
+            charCount = 0;
+            cursor = tokenStart;
+
+            while (*cursor != delimiter && *cursor != '\0') {
+                if (*cursor == '\\')
+                    ++cursor;
+
+                assert(*cursor != '\0');
+
+                token[charCount++] = *cursor++;
+            }
+            token[charCount] = '\0';
+            
+            *tokenP = token;
+            *nextP = cursor;
+        }
+    }
+}
+
+
+
+
+
+
+