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new `read' option `*u' (read-until) + simpler implementation for `read'

v5-2
Roberto Ierusalimschy 24 years ago
parent
777061e441
commit
9559c111a3
1 changed files with 84 additions and 78 deletions
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  1. 162
      liolib.c

162
liolib.c
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@ -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 */

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