/* -*-c-*-
*
- * $Id: scan.c,v 1.1 1999/07/01 08:56:23 mdw Exp $
+ * $Id: scan.c,v 1.2 1999/07/26 23:24:33 mdw Exp $
*
* Character scanners
*
- * (c) 1999 Mark Wooding
+ * (c) 1999 Straylight/Edgeware
*/
/*----- Licensing notice --------------------------------------------------*
/*----- Revision history --------------------------------------------------*
*
* $Log: scan.c,v $
- * Revision 1.1 1999/07/01 08:56:23 mdw
- * Initial revision
+ * Revision 1.2 1999/07/26 23:24:33 mdw
+ * Complete rewrite. Allow a list of character sources to enable changes
+ * during parsing of syntactic constructs.
+ *
+ * Revision 1.1.1.1 1999/07/01 08:56:23 mdw
+ * Initial revision.
*
*/
#include <string.h>
#include <mLib/dstr.h>
+#include <mLib/sub.h>
#include "scan.h"
-/*----- Main code ---------------------------------------------------------*/
+/*----- File scanner source -----------------------------------------------*/
+
+/* --- File scanner block --- */
+
+typedef struct fscan {
+ scansrc ss;
+ FILE *fp;
+ unsigned f;
+} fscan;
-/* --- Generic scanner setup --- */
+/* --- @scan@ --- */
-static void scan_init(scanner *sc, scan_ops *ops, const char *src)
+static int fscan_scan(scansrc *ss)
{
- sc->ops = ops;
- sc->line = 1;
- sc->src = src;
- dstr_create(&sc->d);
+ fscan *fs = (fscan *)ss;
+ int ch = getc(fs->fp);
+ if (ch == '\n')
+ fs->ss.line++;
+ return (ch);
}
-/* --- @argv@ scanner --- */
+/* --- @destroy@ --- */
-static int argv_scan(void *p)
+static void fscan_destroy(scansrc *ss)
{
- scan_argvctx *c = p;
- int ch;
+ fscan *fs = (fscan *)ss;
+ if (!(fs->f & SCF_NOCLOSE))
+ fclose(fs->fp);
+ if (fs->f & SCF_FREENAME)
+ free(fs->ss.src);
+ DESTROY(fs);
+}
- if (c->ch != EOF) {
- ch = c->ch;
- c->ch = EOF;
- } else if (*c->p)
- ch = *c->p++;
- else if (*c->pp) {
- c->p = *c->pp++;
- ch = '\n';
- } else
- ch = EOF;
+/* --- File scanner operations --- */
+
+static scansrc_ops fscan_ops = { fscan_scan, fscan_destroy };
+
+/* --- @scan_file@ --- *
+ *
+ * Arguments: @FILE *fp@ = pointer to file descriptor
+ * @char *name@ = pointer to source file name
+ * @unsigned f@ = flags
+ *
+ * Returns: A scanner source.
+ *
+ * Use: Creates a new scanner source for reading from a file.
+ */
+
+scansrc *scan_file(FILE *fp, char *name, unsigned f)
+{
+ fscan *fs = CREATE(fs);
+ fs->ss.ops = &fscan_ops;
+ fs->ss.src = name;
+ fs->ss.line = 1;
+ fs->fp = fp;
+ fs->f = f;
+ return (&fs->ss);
+}
+
+/*---- Argv scanner source ------------------------------------------------*/
+
+/* --- Argv scanner block --- */
+
+typedef struct avscan {
+ scansrc ss;
+ char **av;
+ char *p;
+} avscan;
+
+/* --- @scan@ --- */
+static int avscan_scan(scansrc *ss)
+{
+ avscan *as = (avscan *)ss;
+ int ch;
+ if (!as->p)
+ ch = EOF;
+ else if ((ch = *as->p++) == 0) {
+ as->ss.line++;
+ as->p = *as->av++;
+ ch = '\n';
+ }
return (ch);
}
-static void argv_unscan(int ch, void *p)
+/* --- @destroy@ --- */
+
+static void avscan_destroy(scansrc *ss)
{
- scan_argvctx *c = p;
- c->ch = ch;
+ avscan *as = (avscan *)ss;
+ DESTROY(as);
}
-void scan_argvinit(scan_argvctx *c, char **pp)
+/* --- Argv scanner operations --- */
+
+static scansrc_ops avscan_ops = { avscan_scan, avscan_destroy };
+
+/* --- @scan_argv@ --- *
+ *
+ * Arguments: @char **av@ = pointer to argument array (null terminated)
+ *
+ * Returns: A scanner source.
+ *
+ * Use: Creates a new scanner source for reading from an @argv@
+ * array.
+ */
+
+scansrc *scan_argv(char **av)
{
- static struct scan_ops ops = { argv_scan, argv_unscan };
- c->p = *pp++;
- c->pp = pp;
- c->ch = EOF;
- scan_init(&c->sc, &ops, "<args>");
+ avscan *as = CREATE(avscan);
+ as->ss.ops = &avscan_ops;
+ as->ss.src = "<argv>";
+ as->ss.line = 1;
+ as->p = *av++;
+ as->av = av;
+ return (&as->ss);
}
-/* --- File scanner --- */
+/*----- End-of-file sentinel block ----------------------------------------*/
+
+/* --- @scan@ --- */
-static int file_scan(void *p)
+static int eof_scan(scansrc *ss)
{
- scan_filectx *c = p;
- return (getc(c->fp));
+ return (EOF);
}
-static void file_unscan(int ch, void *p)
+/* --- @destroy@ --- */
+
+static void eof_destroy(scansrc *ss)
{
- scan_filectx *c = p;
- ungetc(ch, c->fp);
+ ;
}
-void scan_fileinit(scan_filectx *c, FILE *fp, const char *file)
+/* --- Eof scanner operations --- */
+
+static scansrc_ops eof_ops = { eof_scan, eof_destroy };
+
+/* --- The end of file marker --- */
+
+static scansrc scan_eof = { &scan_eof, &eof_ops, "<eof>", 0, EOF };
+
+/*----- General scanner handling ------------------------------------------*/
+
+/* --- @scan@ --- *
+ *
+ * Arguments: @scanner *sc@ = pointer to main scanner context
+ *
+ * Returns: Character read, or end-of-file.
+ *
+ * Use: Scans a character from a source of characters.
+ */
+
+int scan(scanner *sc)
+{
+ int ch;
+ if (sc->head->pushback != EOF) {
+ ch = sc->head->pushback;
+ sc->head->pushback = EOF;
+ } else {
+ scansrc *ss = sc->head;
+ if (ss == &scan_eof)
+ ch = EOF;
+ else if ((ch = ss->ops->scan(ss)) == EOF) {
+ sc->head = ss->next;
+ if (sc->head == &scan_eof)
+ sc->tail = &sc->head;
+ ss->ops->destroy(ss);
+ ch = '\n';
+ }
+ }
+ return (ch);
+}
+
+/* --- @unscan@ --- *
+ *
+ * Arguments: @scanner *sc@ = pointer to main scanner context
+ * @int ch@ = character to unscan
+ *
+ * Returns: ---
+ *
+ * Use: Scans a character from a source of characters.
+ */
+
+void unscan(scanner *sc, int ch)
+{
+ sc->head->pushback = ch;
+}
+
+/* --- @scan_push@ --- *
+ *
+ * Arguments: @scanner *sc@ = pointer to main scanner context
+ * @scansrc *ss@ = souorce to push
+ *
+ * Returns: ---
+ *
+ * Use: Pushes a scanner source onto the front of the queue.
+ */
+
+void scan_push(scanner *sc, scansrc *ss)
{
- static struct scan_ops ops = { file_scan, file_unscan };
- c->fp = fp;
- scan_init(&c->sc, &ops, file);
+ ss->next = sc->head;
+ if (sc->head == &scan_eof)
+ sc->tail = &ss->next;
+ sc->head = ss;
+ ss->pushback = EOF;
+ ss->tok = 0;
+ ss->t = 0;
}
-/* --- Miscellaneous functions --- */
+/* --- @scan_add@ --- *
+ *
+ * Arguments: @scanner *sc@ = pointer to main scanner context
+ * @scansrc *ss@ = souorce to push
+ *
+ * Returns: ---
+ *
+ * Use: Adds a scanner source onto the end of the queue.
+ */
+
+void scan_add(scanner *sc, scansrc *ss)
+{
+ ss->next = &scan_eof;
+ *sc->tail = ss;
+ sc->tail = &ss->next;
+ ss->pushback = EOF;
+ ss->tok = 0;
+ ss->t = 0;
+}
+
+/* --- @scan_create@ --- *
+ *
+ * Arguments: @scanner *sc@ = scanner context to initialize
+ *
+ * Returns: ---
+ *
+ * Use: Initializes a scanner block ready for use.
+ */
+
+void scan_create(scanner *sc)
+{
+ sc->head = &scan_eof;
+ sc->tail = &sc->head;
+ dstr_create(&sc->d);
+}
+
+/* --- @scan_destroy@ --- *
+ *
+ * Arguments: @scanner *sc@ = pointer to scanner context
+ *
+ * Returns: ---
+ *
+ * Use: Destroys a scanner and all the sources attached to it.
+ */
-void scan_destroy(void *p)
+void scan_destroy(scanner *sc)
{
- scanner *sc = p;
+ scansrc *ss = sc->head;
+ while (ss != &scan_eof) {
+ scansrc *sss = ss;
+ ss = ss->next;
+ if (sss->tok)
+ free(sss->tok);
+ sss->ops->destroy(sss);
+ }
dstr_destroy(&sc->d);
+ if (scan_eof.tok)
+ free(scan_eof.tok);
+ scan_eof.tok = 0;
+ sc->head = &scan_eof;
+ sc->tail = &sc->head;
}
/*----- That's all, folks -------------------------------------------------*/
~mdw / fwd / blobdiff