/**************************************************************************** * libc/stdio/lib_sscanf.c * * Copyright (C) 2007, 2008, 2011-2014, 2016 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. 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. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * 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. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include #include /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #define MAXLN 128 #ifndef MIN # define MIN(a,b) (((a) < (b)) ? (a) : (b)) #endif #ifndef MAX # define MAX(a,b) (((a) > (b)) ? (a) : (b)) #endif /**************************************************************************** * Public Function Prototypes ****************************************************************************/ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap); /**************************************************************************** * Private Data ****************************************************************************/ static const char spaces[] = " \t\n\r\f\v"; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Function: findwidth * * Description: * Try to figure out the width of the input data. * ****************************************************************************/ static int findwidth(FAR const char *buf, FAR const char *fmt) { FAR const char *next = fmt + 1; /* No... is there a space after the format? Or does the format string end * here? */ if (isspace(*next) || *next == 0) { /* Use the input up until the first white space is encountered. */ return strcspn(buf, spaces); } /* No.. Another possibility is the format character is followed by * some recognizable delimiting value. */ if (*next != '%') { /* If so we will say that the string ends there if we can find that * delimiter in the input string. */ FAR const char *ptr = strchr(buf, *next); if (ptr) { return (int)(ptr - buf); } } /* No... the format has no delimiter and is back-to-back with the next * format (or is followed by a delimiter that does not exist in the * input string). At this point we just bail and Use the input up until * the first white space is encountered. * * NOTE: This means that values from the following format may be * concatenated with the first. This is a bug. We have no generic way of * determining the width of the data if there is no fieldwidth, no space * separating the input, and no usable delimiter character. */ return strcspn(buf, spaces); } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Function: sscanf * * Description: * ANSI standard sscanf implementation. * ****************************************************************************/ int sscanf(FAR const char *buf, FAR const char *fmt, ...) { va_list ap; int count; va_start(ap, fmt); count = vsscanf((FAR const char *)buf, fmt, ap); va_end(ap); return count; } /**************************************************************************** * Function: vsscanf * * Description: * ANSI standard vsscanf implementation. * ****************************************************************************/ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap) { FAR const char *bufstart; FAR char *tv; FAR const char *tc; bool lflag; bool noassign; int count; int width; int fwidth; int base = 10; char tmp[MAXLN]; linfo("vsscanf: buf=\"%s\" fmt=\"%s\"\n", buf, fmt); /* Remember the start of the input buffer. We will need this for %n * calculations. */ bufstart = buf; /* Parse the format, extracting values from the input buffer as needed */ count = 0; width = 0; noassign = false; lflag = false; /* Loop until all characters in the fmt string have been processed. We * may have to continue loop after reaching the end the input data in * order to handle trailing %n format specifiers. */ while (*fmt) { /* Skip over white space */ while (isspace(*fmt)) { fmt++; } /* Check for a conversion specifier */ if (*fmt == '%') { linfo("vsscanf: Specifier found\n"); /* Check for qualifiers on the conversion specifier */ fmt++; for (; *fmt; fmt++) { linfo("vsscanf: Processing %c\n", *fmt); if (strchr("dibouxcsefgn%", *fmt)) { break; } if (*fmt == '*') { noassign = true; } else if (*fmt == 'l' || *fmt == 'L') { /* NOTE: Missing check for long long ('ll') */ lflag = true; } else if (*fmt >= '1' && *fmt <= '9') { for (tc = fmt; isdigit(*fmt); fmt++); strncpy(tmp, tc, fmt - tc); tmp[fmt - tc] = '\0'; width = atoi(tmp); fmt--; } } /* Process %s: String conversion */ if (*fmt == 's') { linfo("vsscanf: Performing string conversion\n"); /* Get a pointer to the char * value. We need to do this even * if we have reached the end of the input data in order to * update the 'ap' variable. */ tv = NULL; /* To avoid warnings about begin uninitialized */ if (!noassign) { tv = va_arg(ap, FAR char *); tv[0] = '\0'; } /* But we only perform the data conversion is we still have * bytes remaining in the input data stream. */ if (*buf) { /* Skip over white space */ while (isspace(*buf)) { buf++; } /* Guess a field width using some heuristics */ fwidth = findwidth(buf, fmt); /* Use the actual field's width if 1) no fieldwidth * specified or 2) the actual field's width is smaller * than fieldwidth specified */ if (!width || fwidth < width) { width = fwidth; } width = MIN(sizeof(tmp) - 1, width); /* Copy the string (if we are making an assignment) */ if (!noassign) { strncpy(tv, buf, width); tv[width] = '\0'; count++; } /* Update the buffer pointer past the string in the input */ buf += width; } } /* Process %c: Character conversion */ else if (*fmt == 'c') { linfo("vsscanf: Performing character conversion\n"); /* Get a pointer to the char * value. We need to do this even * if we have reached the end of the input data in order to * update the 'ap' variable. */ tv = NULL; /* To avoid warnings about beign uninitialized */ if (!noassign) { tv = va_arg(ap, FAR char *); tv[0] = '\0'; } /* But we only perform the data conversion is we still have * bytes remaining in the input data stream. */ if (*buf) { /* Was a field width specified? */ if (!width) { /* No, then width is this one single character */ width = 1; } /* Copy the character(s) (if we are making an assignment) */ if (!noassign) { strncpy(tv, buf, width); tv[width] = '\0'; count++; } /* Update the buffer pointer past the character(s) in the * input */ buf += width; } } /* Process %d, %o, %b, %x, %u: Various integer conversions */ else if (strchr("dobxu", *fmt)) { FAR long *plong = NULL; FAR int *pint = NULL; bool sign; linfo("vsscanf: Performing integer conversion\n"); /* Get a pointer to the integer value. We need to do this even * if we have reached the end of the input data in order to * update the 'ap' variable. */ if (!noassign) { /* We have to check whether we need to return a long or an * int. */ if (lflag) { plong = va_arg(ap, FAR long *); *plong = 0; } else { pint = va_arg(ap, FAR int *); *pint = 0; } } /* But we only perform the data conversion if we still have * bytes remaining in the input data stream. */ if (*buf) { FAR char *endptr; int errsave; long tmplong; /* Skip over any white space before the integer string */ while (isspace(*buf)) { buf++; } /* The base of the integer conversion depends on the * specific conversion specification. */ sign = false; switch (*fmt) { default: case 'd': sign = true; case 'u': base = 10; break; case 'X': case 'x': base = 16; break; case 'o': base = 8; break; case 'b': base = 2; break; } /* Was a field width specified? */ if (!width) { /* No... Guess a field width using some heuristics */ int tmpwidth = findwidth(buf, fmt); width = MIN(sizeof(tmp) - 1, tmpwidth); } /* Copy the numeric string into a temporary working * buffer. */ strncpy(tmp, buf, width); tmp[width] = '\0'; linfo("vsscanf: tmp[]=\"%s\"\n", tmp); /* Perform the integer conversion */ /* Preserve the errno value */ errsave = get_errno(); set_errno(0); if (sign) { tmplong = strtol(tmp, &endptr, base); } else { tmplong = strtoul(tmp, &endptr, base); } /* Check if the number was successfully converted */ if (tmp == endptr || get_errno() == ERANGE) { return count; } /* Move by the actual number of characters converted */ buf += (endptr - tmp); set_errno(errsave); if (!noassign) { /* We have to check whether we need to return a long * or an int. */ if (lflag) { linfo("vsscanf: Return %ld to 0x%p\n", tmplong, plong); *plong = tmplong; } else { linfo("vsscanf: Return %ld to 0x%p\n", tmplong, pint); *pint = (int)tmplong; } count++; } } } /* Process %a, %A, %f, %F, %e, %E, %g, and %G: Floating point * conversions */ else if (strchr("aAfFeEgG", *fmt) != NULL) { #ifdef CONFIG_HAVE_DOUBLE FAR double *pd = NULL; #endif FAR float *pf = NULL; linfo("vsscanf: Performing floating point conversion\n"); /* Get a pointer to the double value. We need to do this even * if we have reached the end of the input data in order to * update the 'ap' variable. */ if (!noassign) { /* We have to check whether we need to return a float or a * double. */ #ifdef CONFIG_HAVE_DOUBLE if (lflag) { pd = va_arg(ap, FAR double *); *pd = 0.0; } else #endif { pf = va_arg(ap, FAR float *); *pf = 0.0; } } #ifdef CONFIG_LIBC_FLOATINGPOINT /* But we only perform the data conversion is we still have * bytes remaining in the input data stream. */ if (*buf) { /* Skip over any white space before the real string */ while (isspace(*buf)) { buf++; } /* Was a fieldwidth specified? */ if (!width) { /* No... Guess a field width using some heuristics */ width = findwidth(buf, fmt); } /* Copy the real string into a temporary working buffer. */ strncpy(tmp, buf, width); tmp[width] = '\0'; buf += width; linfo("vsscanf: tmp[]=\"%s\"\n", tmp); /* Perform the floating point conversion */ if (!noassign) { /* strtod always returns a double */ FAR char *endptr; int errsave; /* Preserve the errno value */ errsave = get_errno(); set_errno(0); /* We have to check whether we need to return a float * or a double. */ #ifdef CONFIG_HAVE_DOUBLE if (lflag) { /* Get the converted double value */ double dvalue = strtod(tmp, &endptr); /* Check if the number was successfully converted */ if (tmp == endptr || get_errno() == ERANGE) { return count; } set_errno(errsave); /* Return the double value */ linfo("vsscanf: Return %f to %p\n", dvalue, pd); *pd = dvalue; } else #endif { /* Get the converted float value */ float fvalue = strtof(tmp, &endptr); /* Check if the number was successfully converted */ if (tmp == endptr || get_errno() == ERANGE) { return count; } set_errno(errsave); /* Return the float value */ linfo("vsscanf: Return %f to %p\n", (double)fvalue, pf); *pf = fvalue; } count++; } } #endif } /* Process %n: Character count */ else if (*fmt == 'n') { linfo("vsscanf: Performing character count\n"); if (!noassign) { size_t nchars = (size_t)(buf - bufstart); /* Note %n does not count as a conversion */ if (lflag) { FAR long *plong = va_arg(ap, FAR long *); *plong = (long)nchars; } else { FAR int *pint = va_arg(ap, FAR int *); *pint = (int)nchars; } } } width = 0; noassign = false; lflag = false; fmt++; } /* It is not a conversion specifier */ else if (*buf) { /* Skip over any leading spaces in the input buffer */ while (isspace(*buf)) { buf++; } /* Skip over matching characters in the buffer and format */ if (*fmt != *buf) { break; } else { fmt++; buf++; } } else { /* NULL terminator encountered */ break; } } /* sscanf is required to return EOF if the input ends before the first * matching failure or conversion. */ return count ? count : EOF; }