kaguya
77 lines
1.5 KiB
C
77 lines
1.5 KiB
C
#include <stdio.h>
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#include <assert.h>
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#ifdef USE_HOST_LIBC
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#define TEST_FILE "ungetc-host-libc.tmp"
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#else
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#define TEST_FILE "ungetc.tmp"
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#endif
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void test(int buffering) {
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FILE *f = fopen(TEST_FILE, "w");
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for(int c = '0'; c <= '9'; c++) {
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fputc(c, f);
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}
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fclose(f);
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f = fopen(TEST_FILE, "r");
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if (!buffering) {
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setbuf(f, NULL);
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}
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assert(ungetc('x', f) == 'x');
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assert(fgetc(f) == 'x');
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// Test pushing back the same character
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for (int c = '0'; c <= '9'; c++) {
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assert(fgetc(f) == c);
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assert(ungetc(c, f) == c);
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assert(fgetc(f) == c);
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}
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assert(fgetc(f) == EOF);
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assert(ungetc(EOF, f) == EOF);
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// Even though the spec does not guarantee it, we should be able to
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// ungetc more than one character.
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assert(ungetc('x', f) == 'x');
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assert(ungetc('y', f) == 'y');
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assert(fgetc(f) == 'y');
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assert(fgetc(f) == 'x');
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// Seeking should discard the effects of ungetc.
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assert(ungetc('x', f) == 'x');
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rewind(f);
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// Test pushing back a different character
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for (int c = '0'; c <= '9'; c++) {
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assert(fgetc(f) == c);
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assert(ungetc(c - '0' + 'a', f) == c - '0' + 'a');
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assert(fgetc(f) == c - '0' + 'a');
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}
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#ifndef USE_HOST_LIBC
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// Too many ungetcs should fail.
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int eof = 0;
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for (int i = 0; i < 100; i++) {
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if (ungetc('x', f) == EOF) {
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eof = 1;
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break;
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}
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}
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assert(eof);
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#endif
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fclose(f);
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// TODO: Test with other operations, like fread.
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}
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int main() {
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fprintf(stderr, "with buffering...\n");
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test(1);
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fprintf(stderr, "without buffering...\n");
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test(0);
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return 0;
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}
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