snark13
737c974400
- Split tests/ (libc feature tests) and examples/ (real apps); shared
app.mk in repo root, was examples/example.mk
- libc/io/* split into libc/{conio,env,errno,file,mouse,string,sys,
time,video}/ — clearer module boundaries
- New examples/mdview/: markdown viewer (Phases 1-5 + light nested
lists). Headers (H1-H4), HR, ulist/olist/quote with nesting via
leading spaces, fenced code blocks, inline emphasis (bold/italic/
underscore/code), wrap/unwrap mode with soft wrap (F2), horizontal
pan (← →) with '>' truncation indicator
- libc additions: scroll() in conio (ESTEX SCROLL), strlwr/strupr,
gets() test
- Makefile updates across tests/ for the new shared app.mk path
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
67 lines
1.8 KiB
C
67 lines
1.8 KiB
C
#include <stdio.h>
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#include <fcntl.h>
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#include <unistd.h>
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/*
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* Exercises lseek() with offsets that span the 16-bit boundary.
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* big.txt is 102400 bytes (100 KB); every 256-byte block opens with a
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* "[off=NNNNNNN] block #BBBB " label, so any seek aligned to 256 lands
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* on a self-identifying marker.
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*/
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static void show_marker(int fd, long off)
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{
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long pos = lseek(fd, off, SEEK_SET);
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printf("\nseek %ld -> pos=%ld\n", off, pos);
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char buf[28];
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int n = read(fd, buf, 27);
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if (n <= 0) {
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printf(" read failed: %d\n", n);
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return;
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}
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buf[n] = 0;
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printf(" bytes: \"%s\"\n", buf);
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}
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int main(void)
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{
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int fd = open("BIG.TXT", O_RDONLY);
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if (fd < 0) {
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printf("open failed: %d\n", fd);
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(void)getchar();
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return 1;
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}
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/* Total file size. */
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long size = lseek(fd, 0L, SEEK_END);
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printf("file size = %ld bytes\n", size);
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/* Seek inside the first 64 KB (high16 = 0). */
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show_marker(fd, 0L);
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show_marker(fd, 256L);
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show_marker(fd, 32768L);
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/* Right at the 64 KB boundary (offset 0x00010000, high16 = 1). */
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show_marker(fd, 65536L);
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/* Past 64 KB (high16 still 1, low16 != 0). */
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show_marker(fd, 65536L + 256L);
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show_marker(fd, 81920L);
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/* Near end of file (size = 102400 = 0x19000, high16 = 1). */
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show_marker(fd, 102400L - 256L);
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/* SEEK_CUR: from current position, +256. After the previous SEEK_SET
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* to 102144, then read of 27 bytes, pos is 102171. +256 -> 102427,
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* which is past EOF — ESTEX should clamp or error. */
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long after_cur = lseek(fd, 256L, SEEK_CUR);
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printf("\nSEEK_CUR +256 -> pos=%ld (past EOF)\n", after_cur);
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close(fd);
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puts("");
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puts("Press any key to exit...");
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(void)getchar();
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return 0;
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}
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