Standard library for strings and pattern-matching

1 files changed, 534 insertions, 0 deletions

diff --git a/lstrlib.c b/lstrlib.c
new file mode 100644
index 00000000..eba282de
--- /dev/null
+++ b/lstrlib.c
@@ -0,0 +1,534 @@
+/*
+** $Id: lstrlib.c,v 1.1 1997/08/14 19:47:57 roberto Exp roberto $
+** Standard library for strings and pattern-matching
+** See Copyright Notice in lua.h
+*/
+
+
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "lauxlib.h"
+#include "lua.h"
+#include "lualib.h"
+
+
+struct lbuff {
+  char *b;
+  size_t max;
+  size_t size;
+};
+
+static struct lbuff lbuffer = {NULL, 0, 0};
+
+
+static char *strbuffer (unsigned long size)
+{
+  if (size > lbuffer.max) {
+    /* ANSI "realloc" doesn't need this test, but some machines (Sun!)
+       don't follow ANSI */
+    lbuffer.b = (lbuffer.b) ? realloc(lbuffer.b, lbuffer.max=size) :
+                              malloc(lbuffer.max=size);
+    if (lbuffer.b == NULL)
+      lua_error("memory overflow");
+  }
+  return lbuffer.b;
+}
+
+
+static char *openspace (unsigned long size)
+{
+  char *buff = strbuffer(lbuffer.size+size);
+  return buff+lbuffer.size;
+}
+
+
+char *luaI_addchar (int c)
+{
+  if (lbuffer.size >= lbuffer.max)
+    strbuffer(lbuffer.max == 0 ? 100 : lbuffer.max*2);
+  lbuffer.b[lbuffer.size++] = c;
+  return lbuffer.b;
+}
+
+
+void luaI_emptybuff (void)
+{
+  lbuffer.size = 0;  /* prepare for next string */
+}
+
+
+static void addnchar (char *s, int n)
+{
+  char *b = openspace(n);
+  strncpy(b, s, n);
+  lbuffer.size += n;
+}
+
+
+static void addstr (char *s)
+{
+  addnchar(s, strlen(s));
+}
+
+
+static void str_len (void)
+{
+ lua_pushnumber(strlen(luaL_check_string(1)));
+}
+
+
+static void str_sub (void)
+{
+  char *s = luaL_check_string(1);
+  long l = strlen(s);
+  long start = (long)luaL_check_number(2);
+  long end = (long)luaL_opt_number(3, -1);
+  if (start < 0) start = l+start+1;
+  if (end < 0) end = l+end+1;
+  if (1 <= start && start <= end && end <= l) {
+    luaI_emptybuff();
+    addnchar(s+start-1, end-start+1);
+    lua_pushstring(luaI_addchar(0));
+  }
+  else lua_pushstring("");
+}
+
+
+static void str_lower (void)
+{
+  char *s;
+  luaI_emptybuff();
+  for (s = luaL_check_string(1); *s; s++)
+    luaI_addchar(tolower((unsigned char)*s));
+  lua_pushstring(luaI_addchar(0));
+}
+
+
+static void str_upper (void)
+{
+  char *s;
+  luaI_emptybuff();
+  for (s = luaL_check_string(1); *s; s++)
+    luaI_addchar(toupper((unsigned char)*s));
+  lua_pushstring(luaI_addchar(0));
+}
+
+static void str_rep (void)
+{
+  char *s = luaL_check_string(1);
+  int n = (int)luaL_check_number(2);
+  luaI_emptybuff();
+  while (n-- > 0)
+    addstr(s);
+  lua_pushstring(luaI_addchar(0));
+}
+
+
+static void str_ascii (void)
+{
+  char *s = luaL_check_string(1);
+  long pos = (long)luaL_opt_number(2, 1) - 1;
+  luaL_arg_check(0<=pos && pos<strlen(s), 2,  "out of range");
+  lua_pushnumber((unsigned char)s[pos]);
+}
+
+
+
+/*
+** =======================================================
+** PATTERN MATCHING
+** =======================================================
+*/
+
+#define MAX_CAPT 9
+
+static struct {
+  char *init;
+  int len;  /* -1 signals unfinished capture */
+} capture[MAX_CAPT];
+
+static int num_captures;  /* only valid after a sucessful call to match */
+
+
+#define ESC     '%'
+#define SPECIALS  "^$*?.([%-"
+
+
+static void push_captures (void)
+{
+  int i;
+  for (i=0; i<num_captures; i++) {
+    int l = capture[i].len;
+    char *buff = openspace(l+1);
+    if (l == -1) lua_error("unfinished capture");
+    strncpy(buff, capture[i].init, l);
+    buff[l] = 0;
+    lua_pushstring(buff);
+  }
+}
+
+
+static int check_cap (int l, int level)
+{
+  l -= '1';
+  if (!(0 <= l && l < level && capture[l].len != -1))
+    lua_error("invalid capture index");
+  return l;
+}
+
+
+static int capture_to_close (int level)
+{
+  for (level--; level>=0; level--)
+    if (capture[level].len == -1) return level;
+  lua_error("invalid pattern capture");
+  return 0;  /* to avoid warnings */
+}
+
+
+static char *bracket_end (char *p)
+{
+  return (*p == 0) ? NULL : strchr((*p=='^') ? p+2 : p+1, ']');
+}
+
+
+static int matchclass (int c, int cl)
+{
+  int res;
+  if (c == 0) return 0;
+  switch (tolower((unsigned char)cl)) {
+    case 'a' : res = isalpha((unsigned char)c); break;
+    case 'c' : res = iscntrl((unsigned char)c); break;
+    case 'd' : res = isdigit((unsigned char)c); break;
+    case 'l' : res = islower((unsigned char)c); break;
+    case 'p' : res = ispunct((unsigned char)c); break;
+    case 's' : res = isspace((unsigned char)c); break;
+    case 'u' : res = isupper((unsigned char)c); break;
+    case 'w' : res = isalnum((unsigned char)c); break;
+    default: return (cl == c);
+  }
+  return (islower((unsigned char)cl) ? res : !res);
+}
+
+
+int luaI_singlematch (int c, char *p, char **ep)
+{
+  switch (*p) {
+    case '\0':
+      *ep = p;
+      return 0;
+    case '.':
+      *ep = p+1;
+      return (c != 0);
+    case ESC:
+      if (*(++p) == '\0')
+        luaL_verror("incorrect pattern (ends with `%c')", ESC);
+      *ep = p+1;
+      return matchclass(c, *p);
+    case '[': {
+      char *end = bracket_end(p+1);
+      int sig = *(p+1) == '^' ? (p++, 0) : 1;
+      if (end == NULL) lua_error("incorrect pattern (missing `]')");
+      *ep = end+1;
+      if (c == 0) return 0;
+      while (++p < end) {
+        if (*p == ESC) {
+          if (((p+1) < end) && matchclass(c, *++p)) return sig;
+        }
+        else if ((*(p+1) == '-') && (p+2 < end)) {
+          p+=2;
+          if (*(p-2) <= c && c <= *p) return sig;
+        }
+        else if (*p == c) return sig;
+      }
+      return !sig;
+    }
+    default:
+      *ep = p+1;
+      return (*p == c);
+  }
+}
+
+
+static char *matchbalance (char *s, int b, int e)
+{
+  if (*s != b) return NULL;
+  else {
+    int cont = 1;
+    while (*(++s)) {
+      if (*s == e) {
+        if (--cont == 0) return s+1;
+      }
+      else if (*s == b) cont++;
+    }
+  }
+  return NULL;  /* string ends out of balance */
+}
+
+
+static char *matchitem (char *s, char *p, int level, char **ep)
+{
+  if (*p == ESC) {
+    p++;
+    if (isdigit((unsigned char)*p)) {  /* capture */
+      int l = check_cap(*p, level);
+      *ep = p+1;
+      if (strncmp(capture[l].init, s, capture[l].len) == 0)
+        return s+capture[l].len;
+      else return NULL;
+    }
+    else if (*p == 'b') {  /* balanced string */
+      p++;
+      if (*p == 0 || *(p+1) == 0)
+        lua_error("bad balanced pattern specification");
+      *ep = p+2;
+      return matchbalance(s, *p, *(p+1));
+    }
+    else p--;  /* and go through */
+  }
+  return (luaI_singlematch(*s, p, ep) ? s+1 : NULL);
+}
+
+
+static char *match (char *s, char *p, int level)
+{
+  init: /* using goto's to optimize tail recursion */
+  switch (*p) {
+    case '(':  /* start capture */
+      if (level >= MAX_CAPT) lua_error("too many captures");
+      capture[level].init = s;
+      capture[level].len = -1;
+      level++; p++; goto init;  /* return match(s, p+1, level); */
+    case ')': {  /* end capture */
+      int l = capture_to_close(level);
+      char *res;
+      capture[l].len = s - capture[l].init;  /* close capture */
+      if ((res = match(s, p+1, level)) == NULL) /* match failed? */
+        capture[l].len = -1;  /* undo capture */
+      return res;
+    }
+    case '\0': case '$':  /* (possibly) end of pattern */
+      if (*p == 0 || (*(p+1) == 0 && *s == 0)) {
+        num_captures = level;
+        return s;
+      }
+      /* else go through */
+    default: {  /* it is a pattern item */
+      char *ep;  /* get what is next */
+      char *s1 = matchitem(s, p, level, &ep);
+      switch (*ep) {
+        case '*': {  /* repetition */
+          char *res;
+          if (s1 && (res = match(s1, p, level)))
+            return res;
+          p=ep+1; goto init;  /* else return match(s, ep+1, level); */
+        }
+        case '-': {  /* repetition */
+          char *res;
+          if ((res = match(s, ep+1, level)) != 0)
+            return res;
+          else if (s1) {
+            s = s1;
+            goto init;  /* return match(s1, p, level); */
+          }
+          else
+            return NULL;
+        }
+        case '?': {  /* optional */
+          char *res;
+          if (s1 && (res = match(s1, ep+1, level)))
+            return res;
+          p=ep+1; goto init;  /* else return match(s, ep+1, level); */
+        }
+        default:
+          if (s1) { s=s1; p=ep; goto init; }  /* return match(s1, ep, level); */
+          else return NULL;
+      }
+    }
+  }
+}
+
+
+static void str_find (void)
+{
+  char *s = luaL_check_string(1);
+  char *p = luaL_check_string(2);
+  long init = (long)luaL_opt_number(3, 1) - 1;
+  luaL_arg_check(0 <= init && init <= strlen(s), 3, "out of range");
+  if (lua_getparam(4) != LUA_NOOBJECT ||
+      strpbrk(p, SPECIALS) == NULL) {  /* no special caracters? */
+    char *s2 = strstr(s+init, p);
+    if (s2) {
+      lua_pushnumber(s2-s+1);
+      lua_pushnumber(s2-s+strlen(p));
+    }
+  }
+  else {
+    int anchor = (*p == '^') ? (p++, 1) : 0;
+    char *s1=s+init;
+    do {
+      char *res;
+      if ((res=match(s1, p, 0)) != NULL) {
+        lua_pushnumber(s1-s+1);  /* start */
+        lua_pushnumber(res-s);   /* end */
+        push_captures();
+        return;
+      }
+    } while (*s1++ && !anchor);
+  }
+}
+
+
+static void add_s (lua_Object newp)
+{
+  if (lua_isstring(newp)) {
+    char *news = lua_getstring(newp);
+    while (*news) {
+      if (*news != ESC || !isdigit((unsigned char)*++news))
+        luaI_addchar(*news++);
+      else {
+        int l = check_cap(*news++, num_captures);
+        addnchar(capture[l].init, capture[l].len);
+      }
+    }
+  }
+  else if (lua_isfunction(newp)) {
+    lua_Object res;
+    struct lbuff oldbuff;
+    int status;
+    lua_beginblock();
+    push_captures();
+    /* function may use lbuffer, so save it and create a luaM_new one */
+    oldbuff = lbuffer;
+    lbuffer.b = NULL; lbuffer.max = lbuffer.size = 0;
+    status = lua_callfunction(newp);
+    /* restore old buffer */
+    free(lbuffer.b);
+    lbuffer = oldbuff;
+    if (status != 0)
+      lua_error(NULL);
+    res = lua_getresult(1);
+    addstr(lua_isstring(res) ? lua_getstring(res) : "");
+    lua_endblock();
+  }
+  else luaL_arg_check(0, 3, NULL);
+}
+
+
+static void str_gsub (void)
+{
+  char *src = luaL_check_string(1);
+  char *p = luaL_check_string(2);
+  lua_Object newp = lua_getparam(3);
+  int max_s = (int)luaL_opt_number(4, strlen(src)+1);
+  int anchor = (*p == '^') ? (p++, 1) : 0;
+  int n = 0;
+  luaI_emptybuff();
+  while (n < max_s) {
+    char *e = match(src, p, 0);
+    if (e) {
+      n++;
+      add_s(newp);
+    }
+    if (e && e>src) /* non empty match? */
+      src = e;  /* skip it */
+    else if (*src)
+      luaI_addchar(*src++);
+    else break;
+    if (anchor) break;
+  }
+  addstr(src);
+  lua_pushstring(luaI_addchar(0));
+  lua_pushnumber(n);  /* number of substitutions */
+}
+
+
+void luaI_addquoted (char *s)
+{
+  luaI_addchar('"');
+  for (; *s; s++) {
+    if (strchr("\"\\\n", *s))
+      luaI_addchar('\\');
+    luaI_addchar(*s);
+  }
+  luaI_addchar('"');
+}
+
+#define MAX_FORMAT 200
+
+static void str_format (void)
+{
+  int arg = 1;
+  char *strfrmt = luaL_check_string(arg);
+  luaI_emptybuff();  /* initialize */
+  while (*strfrmt) {
+    if (*strfrmt != '%')
+      luaI_addchar(*strfrmt++);
+    else if (*++strfrmt == '%')
+      luaI_addchar(*strfrmt++);  /* %% */
+    else { /* format item */
+      char form[MAX_FORMAT];      /* store the format ('%...') */
+      char *buff;
+      char *initf = strfrmt;
+      form[0] = '%';
+      strfrmt = match(strfrmt, "%d?%$?[-+ #]*(%d*)%.?(%d*)", 0);
+      if (capture[0].len > 3 || capture[1].len > 3)  /* < 1000? */
+        lua_error("invalid format (width or precision too long)");
+      if (isdigit((unsigned char)initf[0]) && initf[1] == '$') {
+        arg = initf[0] - '0';
+        initf += 2;  /* skip the 'n$' */
+      }
+      arg++;
+      strncpy(form+1, initf, strfrmt-initf+1); /* +1 to include convertion */
+      form[strfrmt-initf+2] = 0;
+      buff = openspace(1000);  /* to store the formated value */
+      switch (*strfrmt++) {
+        case 'q':
+          luaI_addquoted(luaL_check_string(arg));
+          continue;
+        case 's': {
+          char *s = luaL_check_string(arg);
+          buff = openspace(strlen(s));
+          sprintf(buff, form, s);
+          break;
+        }
+        case 'c':  case 'd':  case 'i': case 'o':
+        case 'u':  case 'x':  case 'X':
+          sprintf(buff, form, (int)luaL_check_number(arg));
+          break;
+        case 'e':  case 'E': case 'f': case 'g': case 'G':
+          sprintf(buff, form, luaL_check_number(arg));
+          break;
+        default:  /* also treat cases 'pnLlh' */
+          lua_error("invalid format option in function `format'");
+      }
+      lbuffer.size += strlen(buff);
+    }
+  }
+  lua_pushstring(luaI_addchar(0));  /* push the result */
+}
+
+
+static struct luaL_reg strlib[] = {
+{"strlen", str_len},
+{"strsub", str_sub},
+{"strlower", str_lower},
+{"strupper", str_upper},
+{"strrep", str_rep},
+{"ascii", str_ascii},
+{"format", str_format},
+{"strfind", str_find},
+{"gsub", str_gsub}
+};
+
+
+/*
+** Open string library
+*/
+void strlib_open (void)
+{
+  luaL_openlib(strlib, (sizeof(strlib)/sizeof(strlib[0])));
+}