31715bd251
92/92 regression tests pass (+ffi-05-string-args).
Covers the four shapes that actually appear at the sx ↔ C boundary
today:
1. [:0]u8 string literal -> const char* (ffi_strlen, ffi_first_byte)
2. sx `string` value via .ptr (slice-decay branch in
coerceArg pulls the pointer)
3. [*]u8 raw buffer + length (ffi_sum_bytes, mutated via
ffi_write_byte and read back)
4. C-returned const char* (round-trips back as [*]u8)
The mutate-via-C path catches any pointer-aliasing regression — sx
allocates the fixed array `bytes : [4]u8`, passes `.ptr` to C which
writes index 1, and the sx side reads `bytes[1]` to confirm the
mutation took effect through the same memory.
26 lines
501 B
C
26 lines
501 B
C
#include "ffi_strings.h"
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int ffi_strlen(const char *s) {
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int n = 0;
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while (s[n] != 0) n++;
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return n;
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}
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int ffi_first_byte(const char *s) {
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return (int)(unsigned char)s[0];
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}
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int ffi_sum_bytes(const unsigned char *buf, int len) {
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int total = 0;
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for (int i = 0; i < len; i++) total += buf[i];
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return total;
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}
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void ffi_write_byte(unsigned char *buf, int idx, unsigned char val) {
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buf[idx] = val;
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}
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const char* ffi_static_greeting(void) {
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return "hello from C";
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}
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