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https://github.com/ibm-s390-linux/s390-tools.git
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d8e5bc07aa
Add function util_concatf() that appends the result of a format string
expansion to the end of an existing string while taking care of the
required memory allocations.
Usage example:
char *str = NULL;
util_concatf(&str, "list:");
for (int i = 1; i <= 3; i++)
util_concatf(&str, "%spart%d", (i > 1 ? "," : ""), i);
printf("%s\n", str); /* list:part1,part2,part3 */
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
70 lines
2.0 KiB
C
70 lines
2.0 KiB
C
/**
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* util_libc_example - Example program for util_libc
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*
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* Copyright IBM Corp. 2016, 2017
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*
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* s390-tools is free software; you can redistribute it and/or modify
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* it under the terms of the MIT license. See LICENSE for details.
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*/
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//! [code]
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "lib/util_libc.h"
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#include "lib/util_panic.h"
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#define EXAMPLE_WORD " /sys/devices/system/cpu "
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/*
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* Demonstrate that out of memory is automatically handled via panic()
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*/
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int main(void)
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{
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unsigned long ulong_max = (unsigned long)-1;
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void *ptr;
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char *zeroes, *str;
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char buffer[sizeof(EXAMPLE_WORD)];
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strcat(buffer, EXAMPLE_WORD);
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fprintf(stderr, "Try to remove leading and trailing spaces from "
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"\"%s\"\nresult = \"%s\"\n", EXAMPLE_WORD,
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util_strstrip(buffer));
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/* Use util_strcat_realloc() for string concatenation */
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fprintf(stderr, "Try to concatenate \"Hello\", \", \" and \"world!\": ");
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str = util_strdup("Hello");
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str = util_strcat_realloc(str, ", ");
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str = util_strcat_realloc(str, "world!");
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fprintf(stderr, "result = \"%s\"\n", str);
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free(str);
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/* Use util_concatf() for string concatenation */
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fprintf(stderr, "Try to concatenate \"list\" plus comma-separated list of numbers 1 to 3: ");
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str = NULL;
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util_concatf(&str, "list:");
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for (int i = 1; i <= 3; i++)
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util_concatf(&str, "%s%d", (i > 1 ? "," : ""), i);
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fprintf(stderr, "result = %s\n", str); /* list:part1,part2,part3 */
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/* One byte allocation should work */
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fprintf(stderr, "Try to allocate 1 byte: ");
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ptr = util_malloc(1);
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fprintf(stderr, "done\n");
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/* One byte zeroed-allocation should work */
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fprintf(stderr, "Try to allocate 1 byte initialized with zeroes: ");
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zeroes = util_zalloc(1);
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fprintf(stderr, "done\n");
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util_assert(*zeroes == 0, "Garbage found in zero initialized memory\n");
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/* The next allocation will probably fail */
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fprintf(stderr, "Try to allocate %lu bytes:\n", ulong_max);
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ptr = util_malloc(ulong_max);
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fprintf(stderr, "You should not see me (ptr=%p)!\n", ptr);
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return EXIT_FAILURE;
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}
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//! [code]
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