output: generic string table implementation

Several output formats use "string tables", which is a collection of
null-terminated (C) strings which are referenced by a byte offset into
the string table.  A single string can be referenced an arbitrary
number of times.

As this is quite simple to implement with a hash table, we do exactly
that.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Makefile.in

@@ -128,6 +128,7 @@ LIBOBJ = stdlib/snprintf.$(O) stdlib/vsnprintf.$(O) stdlib/strlcpy.$(O) \
 	macros/macros.$(O) \
 	\
 	output/outform.$(O) output/outlib.$(O) output/legacy.$(O) \
+	output/strtbl.$(O) \
 	output/nulldbg.$(O) output/nullout.$(O) \
 	output/outbin.$(O) output/outaout.$(O) output/outcoff.$(O) \
 	output/outelf.$(O) \
@@ -759,6 +760,11 @@ output/outrdf2.$(O): output/outrdf2.c asm/directiv.h asm/pptok.h \
  include/nasmint.h include/nasmlib.h include/opflags.h include/perfhash.h \
  include/rdoff.h include/saa.h include/strlist.h include/tables.h \
  output/outform.h output/outlib.h x86/insnsi.h x86/regs.h
+output/strtbl.$(O): output/strtbl.c asm/directiv.h asm/pptok.h asm/preproc.h \
+ config/config.h config/msvc.h config/unknown.h config/watcom.h \
+ include/compiler.h include/error.h include/hashtbl.h include/nasm.h \
+ include/nasmint.h include/nasmlib.h include/opflags.h include/perfhash.h \
+ include/strlist.h include/tables.h output/strtbl.h x86/insnsi.h x86/regs.h
 rdoff/collectn.$(O): rdoff/collectn.c config/config.h config/msvc.h \
  config/unknown.h config/watcom.h include/compiler.h include/error.h \
  include/nasmint.h include/nasmlib.h include/rdoff.h rdoff/collectn.h \

Mkfiles/msvc.mak

@@ -101,6 +101,7 @@ LIBOBJ = stdlib\snprintf.$(O) stdlib\vsnprintf.$(O) stdlib\strlcpy.$(O) \
 	macros\macros.$(O) \
 	\
 	output\outform.$(O) output\outlib.$(O) output\legacy.$(O) \
+	output\strtbl.$(O) \
 	output\nulldbg.$(O) output\nullout.$(O) \
 	output\outbin.$(O) output\outaout.$(O) output\outcoff.$(O) \
 	output\outelf.$(O) \
@@ -645,6 +646,11 @@ output\outrdf2.$(O): output\outrdf2.c asm\directiv.h asm\pptok.h \
  include\nasmlib.h include\opflags.h include\perfhash.h include\rdoff.h \
  include\saa.h include\strlist.h include\tables.h output\outform.h \
  output\outlib.h x86\insnsi.h x86\regs.h
+output\strtbl.$(O): output\strtbl.c asm\directiv.h asm\pptok.h asm\preproc.h \
+ config\msvc.h config\unknown.h config\watcom.h include\compiler.h \
+ include\error.h include\hashtbl.h include\nasm.h include\nasmint.h \
+ include\nasmlib.h include\opflags.h include\perfhash.h include\strlist.h \
+ include\tables.h output\strtbl.h x86\insnsi.h x86\regs.h
 rdoff\collectn.$(O): rdoff\collectn.c config\msvc.h config\unknown.h \
  config\watcom.h include\compiler.h include\error.h include\nasmint.h \
  include\nasmlib.h include\rdoff.h rdoff\collectn.h rdoff\rdfutils.h

Mkfiles/openwcom.mak

@@ -87,6 +87,7 @@ LIBOBJ = stdlib/snprintf.$(O) stdlib/vsnprintf.$(O) stdlib/strlcpy.$(O) &
 	macros/macros.$(O) &
 	&
 	output/outform.$(O) output/outlib.$(O) output/legacy.$(O) &
+	output/strtbl.$(O) &
 	output/nulldbg.$(O) output/nullout.$(O) &
 	output/outbin.$(O) output/outaout.$(O) output/outcoff.$(O) &
 	output/outelf.$(O) &
@@ -619,6 +620,11 @@ output/outrdf2.$(O): output/outrdf2.c asm/directiv.h asm/pptok.h &
  include/nasmlib.h include/opflags.h include/perfhash.h include/rdoff.h &
  include/saa.h include/strlist.h include/tables.h output/outform.h &
  output/outlib.h x86/insnsi.h x86/regs.h
+output/strtbl.$(O): output/strtbl.c asm/directiv.h asm/pptok.h asm/preproc.h &
+ config/msvc.h config/unknown.h config/watcom.h include/compiler.h &
+ include/error.h include/hashtbl.h include/nasm.h include/nasmint.h &
+ include/nasmlib.h include/opflags.h include/perfhash.h include/strlist.h &
+ include/tables.h output/strtbl.h x86/insnsi.h x86/regs.h
 rdoff/collectn.$(O): rdoff/collectn.c config/msvc.h config/unknown.h &
  config/watcom.h include/compiler.h include/error.h include/nasmint.h &
  include/nasmlib.h include/rdoff.h rdoff/collectn.h rdoff/rdfutils.h

output/strtbl.c

@@ -0,0 +1,111 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2017 The NASM Authors - All Rights Reserved
+ *   See the file AUTHORS included with the NASM distribution for
+ *   the specific copyright holders.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following
+ *   conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ *     copyright notice, this list of conditions and the following
+ *     disclaimer in the documentation and/or other materials provided
+ *     with the distribution.
+ *
+ *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * Common string table handling
+ *
+ * A number of output formats use a "string table"; a container for
+ * a number of strings which may be reused at will.  This implements
+ * a string table which eliminates duplicates and returns the index
+ * into the string table when queried.
+ */
+
+#include "compiler.h"
+
+#include "nasm.h"
+#include "nasmlib.h"
+#include "error.h"
+#include "strtbl.h"
+
+struct strtbl_entry {
+    size_t index;
+    size_t bytes;
+    char str[1];
+};
+
+void strtbl_init(struct nasm_strtbl *tbl)
+{
+    tbl->size = 0;
+    hash_init(&tbl->hash, HASH_LARGE);
+    strtbl_find(tbl, "", true); /* Index 0 is always an empty string */
+}
+
+void strtbl_free(struct nasm_strtbl *tbl)
+{
+    struct hash_tbl_node *iter = NULL;
+    struct strtbl_entry *se;
+
+    while ((se = hash_iterate(&tbl->hash, &iter, NULL)))
+        nasm_free(se);
+
+    hash_free(&tbl->hash);
+}
+
+size_t strtbl_find(struct nasm_strtbl *tbl, const char *str, bool add)
+{
+    struct hash_insert hi;
+    void **dp;
+    struct strtbl_entry *se;
+
+    dp = hash_find(&tbl->hash, str, &hi);
+    if (dp) {
+        se = *dp;
+    } else if (add) {
+        size_t bytes = strlen(str) + 1;
+
+        se = nasm_malloc(sizeof(struct strtbl_entry)-1+bytes);
+        se->index = tbl->size;
+        tbl->size += bytes;
+        se->bytes = bytes;
+        memcpy(se->str, str, bytes);
+
+        hash_add(&hi, se->str, se);
+    } else {
+        return STRTBL_NONE;
+    }
+
+    return se->index;
+}
+
+/* This create a linearized buffer containing the actual string table */
+void *strtbl_generate(const struct nasm_strtbl *tbl)
+{
+    char *buf = nasm_malloc(strtbl_size(tbl));
+    struct hash_tbl_node *iter = NULL;
+    struct strtbl_entry *se;
+
+    while ((se = hash_iterate(&tbl->hash, &iter, NULL)))
+        memcpy(buf + se->index, se->str, se->bytes);
+
+    return buf;
+}

output/strtbl.h

@@ -0,0 +1,56 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2017 The NASM Authors - All Rights Reserved
+ *   See the file AUTHORS included with the NASM distribution for
+ *   the specific copyright holders.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following
+ *   conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ *     copyright notice, this list of conditions and the following
+ *     disclaimer in the documentation and/or other materials provided
+ *     with the distribution.
+ *
+ *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * ----------------------------------------------------------------------- */
+
+#ifndef NASM_STRTBL_H
+#define NASM_STRTBL_H
+
+#include "compiler.h"
+#include "hashtbl.h"
+
+struct nasm_strtbl {
+    size_t size;
+    struct hash_table hash;
+};
+
+#define STRTBL_NONE ((size_t)-1)
+
+void strtbl_init(struct nasm_strtbl *tbl);
+void strtbl_free(struct nasm_strtbl *tbl);
+size_t strtbl_find(struct nasm_strtbl *tbl, const char *str, bool add);
+static inline size_t strtbl_size(const struct nasm_strtbl *tbl)
+{
+    return tbl->size;
+}
+void * safe_alloc strtbl_generate(const struct nasm_strtbl *tbl);
+
+#endif /* NASM_STRTBL_H */