commit 9559c111a32479794acc59fba2cbeab365a567f3
parent 777061e441ecbb9e3522aa5c88d9204decc9ff81
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Fri, 22 Jun 2001 10:49:20 -0300
new `read' option `*u' (read-until) + simpler implementation for `read'
Diffstat:
| M | liolib.c | | | 162 | +++++++++++++++++++++++++++++++++++++++++-------------------------------------- |
1 file changed, 84 insertions(+), 78 deletions(-)
diff --git a/liolib.c b/liolib.c
@@ -1,5 +1,5 @@
/*
-** $Id: liolib.c,v 1.114 2001/06/07 13:46:29 roberto Exp roberto $
+** $Id: liolib.c,v 1.115 2001/06/08 16:48:32 roberto Exp roberto $
** Standard I/O (and system) library
** See Copyright Notice in lua.h
*/
@@ -205,115 +205,114 @@ static int io_appendto (lua_State *L) {
*/
-static int read_number (lua_State *L, FILE *f) {
- double d;
- if (fscanf(f, l_s("%lf"), &d) == 1) {
- lua_pushnumber(L, d);
- return 1;
+#ifndef LUA_MAXUNTIL
+#define LUA_MAXUNTIL 100
+#endif
+
+
+/*
+** Knuth-Morris-Pratt algorithm for string searching
+** (based on `Algorithms in MODULA-3', Robert Sedgewick;
+** Addison-Wesley, 1993.)
+*/
+
+static void prep_read_until (int next[], const l_char *p, int pl) {
+ int i = 0;
+ int j = -1;
+ next[0] = -1;
+ while (i < pl) {
+ if (j == -1 || p[i] == p[j]) {
+ i++; j++; next[i] = j;
+ }
+ else j = next[j];
}
- else return 0; /* read fails */
}
-static int read_word (lua_State *L, FILE *f) {
+static int read_until (lua_State *L, FILE *f, const l_char *p, int pl) {
l_charint c;
+ int j;
+ int next[LUA_MAXUNTIL+1];
luaL_Buffer b;
luaL_buffinit(L, &b);
- do { c = fgetc(f); } while (isspace(c)); /* skip spaces */
- while (c != EOF && !isspace(c)) {
- luaL_putchar(&b, c);
- c = fgetc(f);
+ prep_read_until(next, p, pl);
+ j = 0;
+ while ((c = fgetc(f)) != EOF) {
+ NoRead:
+ if (c == p[j]) {
+ j++; /* go to next char in pattern */
+ if (j == pl) { /* complete match? */
+ luaL_pushresult(&b); /* close buffer */
+ return 1; /* always success */
+ }
+ }
+ else if (j == 0)
+ luaL_putchar(&b, c);
+ else { /* match fail */
+ luaL_addlstring(&b, p, j - next[j]); /* put failed part on result */
+ j = next[j]; /* backtrack pattern index */
+ goto NoRead; /* repeat without reading next char */
+ }
}
- ungetc(c, f);
+ /* end of file without a match */
+ luaL_addlstring(&b, p, j); /* put failed part on result */
luaL_pushresult(&b); /* close buffer */
return (lua_strlen(L, -1) > 0);
}
-static int read_line (lua_State *L, FILE *f) {
- int n = 0;
- luaL_Buffer b;
- luaL_buffinit(L, &b);
- for (;;) {
- l_char *p = luaL_prepbuffer(&b);
- if (!fgets(p, LUAL_BUFFERSIZE, f)) /* read fails? */
- break;
- n = strlen(p);
- if (p[n-1] != l_c('\n'))
- luaL_addsize(&b, n);
- else {
- luaL_addsize(&b, n-1); /* do not add the `\n' */
- break;
- }
+static int read_number (lua_State *L, FILE *f) {
+ double d;
+ if (fscanf(f, l_s("%lf"), &d) == 1) {
+ lua_pushnumber(L, d);
+ return 1;
}
- luaL_pushresult(&b); /* close buffer */
- return (n > 0); /* read something? */
+ else return 0; /* read fails */
}
-static void read_file (lua_State *L, FILE *f) {
- size_t len = 0;
- size_t size = LUAL_BUFFERSIZE;
- size_t oldsize = 0;
- l_char *buffer = NULL;
- for (;;) {
- l_char *newbuffer = (l_char *)l_realloc(buffer, oldsize, size);
- if (newbuffer == NULL) {
- l_free(buffer, oldsize);
- lua_error(L, l_s("not enough memory to read a file"));
- }
- buffer = newbuffer;
- len += fread(buffer+len, sizeof(l_char), size-len, f);
- if (len < size) break; /* did not read all it could */
- oldsize = size;
- size *= 2;
- }
- lua_pushlstring(L, buffer, len);
- l_free(buffer, size);
+static int test_eof (lua_State *L, FILE *f) {
+ l_charint c = fgetc(f);
+ ungetc(c, f);
+ lua_pushlstring(L, NULL, 0);
+ return (c != EOF);
}
static int read_chars (lua_State *L, FILE *f, size_t n) {
- if (n == 0) { /* test eof? */
- l_charint c = fgetc(f);
- ungetc(c, f);
- lua_pushlstring(L, NULL, 0);
- return (c != EOF);
- }
- else {
- l_char *buffer;
- size_t n1;
- l_char statbuff[LUAL_BUFFERSIZE];
- if (n <= LUAL_BUFFERSIZE)
- buffer = statbuff;
- else {
- buffer = (l_char *)l_malloc(n);
- if (buffer == NULL)
- lua_error(L, l_s("not enough memory to read a file"));
- }
- n1 = fread(buffer, sizeof(l_char), n, f);
- lua_pushlstring(L, buffer, n1);
- if (buffer != statbuff) l_free(buffer, n);
- return (n1 > 0 || n == 0);
- }
+ size_t rlen;
+ luaL_Buffer b;
+ luaL_buffinit(L, &b);
+ rlen = LUAL_BUFFERSIZE;
+ do {
+ l_char *p = luaL_prepbuffer(&b);
+ if (rlen > n) rlen = n;
+ rlen = fread(p, sizeof(l_char), rlen, f);
+ luaL_addsize(&b, rlen);
+ n -= rlen;
+ } while (n > 0 && rlen > 0); /* until end of count or eof */
+ luaL_pushresult(&b); /* close buffer */
+ return (n == 0 || lua_strlen(L, -1) > 0);
}
static int io_read (lua_State *L) {
FILE *f = getopthandle(L, INFILE);
- int nargs = lua_gettop(L)-1;
+ int nargs = lua_gettop(L) - 1;
int success;
int n;
if (nargs == 0) { /* no arguments? */
- success = read_line(L, f);
+ success = read_until(L, f, l_s("\n"), 1); /* read until \n (a line) */
n = 2; /* will return n-1 results */
}
else { /* ensure stack space for all results and for auxlib's buffer */
luaL_checkstack(L, nargs+LUA_MINSTACK, l_s("too many arguments"));
success = 1;
for (n = 1; n<=nargs && success; n++) {
- if (lua_type(L, n) == LUA_TNUMBER)
- success = read_chars(L, f, (size_t)lua_tonumber(L, n));
+ if (lua_type(L, n) == LUA_TNUMBER) {
+ size_t l = (size_t)lua_tonumber(L, n);
+ success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l);
+ }
else {
const l_char *p = lua_tostring(L, n);
if (!p || p[0] != l_c('*'))
@@ -323,15 +322,22 @@ static int io_read (lua_State *L) {
success = read_number(L, f);
break;
case l_c('l'): /* line */
- success = read_line(L, f);
+ success = read_until(L, f, l_s("\n"), 1); /* read until \n */
break;
case l_c('a'): /* file */
- read_file(L, f);
+ read_chars(L, f, ~((size_t)0)); /* read MAX_SIZE_T chars */
success = 1; /* always success */
break;
case l_c('w'): /* word */
- success = read_word(L, f);
+ lua_error(L, "option `*w' is deprecated");
+ break;
+ case l_c('u'): { /* read until */
+ size_t pl = lua_strlen(L, n) - 2;
+ luaL_arg_check(L, 0 < pl && pl <= LUA_MAXUNTIL, n,
+ l_s("invalid read-until length"));
+ success = read_until(L, f, p+2, (int)pl);
break;
+ }
default:
luaL_argerror(L, n, l_s("invalid format"));
success = 0; /* to avoid warnings */
