Add string array, have the pdfio_file_t object manage allocated data.

pdfio-string.c

@@ -0,0 +1,132 @@
+//
+// PDF dictionary functions for pdfio.
+//
+// Copyright © 2021 by Michael R Sweet.
+//
+// Licensed under Apache License v2.0.  See the file "LICENSE" for more
+// information.
+//
+
+//
+// Include necessary headers...
+//
+
+#include "pdfio-private.h"
+
+
+//
+// Local functions...
+//
+
+static int	compare_strings(char **a, char **b);
+
+
+//
+// 'pdfioStringCreate()' - Create a literal string.
+//
+// This function creates a literal string associated with the PDF file
+// "pwg".  The "s" string points to a nul-terminated C string.
+//
+// `NULL` is returned on error, otherwise a `char *` that is valid until
+// `pdfioFileClose` is called.
+//
+
+char *					// O - New string or `NULL` on error
+pdfioStringCreate(
+    pdfio_file_t *pdf,			// I - PDF file
+    const char   *s)			// I - Nul-terminated string
+{
+  char	*news;				// New string
+
+
+  // Range check input...
+  if (!pdf || !s)
+    return (NULL);
+
+  // See if the string has already been added...
+  if (pdf->num_strings > 0 && (news = (char *)bsearch(&s, pdf->strings, pdf->num_strings, sizeof(char *), (int (*)(const void *, const void *))compare_strings)) != NULL)
+    return (news);
+
+  // Not already added, so add it...
+  if ((news = strdup(s)) == NULL)
+    return (NULL);
+
+  if (pdf->num_strings >= pdf->alloc_strings)
+  {
+    // Expand the string array...
+    char **temp = realloc(pdf->strings, (pdf->alloc_strings + 32) * sizeof(char *));
+
+    if (!temp)
+      return (NULL);
+
+    pdf->strings       = temp;
+    pdf->alloc_strings += 32;
+  }
+
+  // TODO: Change to insertion sort as needed...
+  pdf->strings[pdf->num_strings ++] = news;
+
+  if (pdf->num_strings > 1)
+    qsort(pdf->strings, pdf->num_strings, sizeof(char *), (int (*)(const void *, const void *))compare_strings);
+
+  return (news);
+}
+
+
+//
+// 'pdfioStringCreatef()' - Create a formatted string.
+//
+// This function creates a formatted string associated with the PDF file
+// "pwg".  The "format" string contains `printf`-style format characters.
+//
+// `NULL` is returned on error, otherwise a `char *` that is valid until
+// `pdfioFileClose` is called.
+//
+
+char *					// O - New string or `NULL` on error
+pdfioStringCreatef(
+    pdfio_file_t *pdf,			// I - PDF file
+    const char   *format,		// I - `printf`-style format string
+    ...)				// I - Additional args as needed
+{
+  char		buffer[8192];		// String buffer
+  va_list	ap;			// Argument list
+
+
+  // Range check input...
+  if (!pdf || !format)
+    return (NULL);
+
+  // Format the string...
+  va_start(ap, format);
+  vsnprintf(buffer, sizeof(buffer), format, ap);
+  va_end(ap);
+
+  // Create the string from the buffer...
+  return (pdfioStringCreate(pdf, buffer));
+}
+
+
+//
+// '()' - Check whether a string has been allocated.
+//
+
+bool					// O - `true` if allocated, `false` otherwise
+_pdfioStringIsAllocated(
+    pdfio_file_t *pdf,			// I - PDF file
+    const char   *s)			// I - String
+{
+  return (pdf->num_strings > 0 && bsearch(&s, pdf->strings, pdf->num_strings, sizeof(char *), (int (*)(const void *, const void *))compare_strings) != NULL);
+}
+
+
+//
+// 'compare_strings()' - Compare two strings.
+//
+
+static int				// O - Result of comparison
+compare_strings(char **a,		// I - First string
+                char **b)		// I - Second string
+{
+  return (strcmp(*a, *b));
+}