252 lines
5.2 KiB
C
252 lines
5.2 KiB
C
// String manipulation functions.
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//
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// Copyright (C) 2008-2013 Kevin O'Connor <kevin@koconnor.net>
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//
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// This file may be distributed under the terms of the GNU LGPLv3 license.
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#include "stacks.h" // yield
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#include "string.h" // memcpy
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#include "farptr.h" // SET_SEG
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/****************************************************************
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* String ops
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****************************************************************/
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// Sum the bytes in the specified area.
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u8
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checksum_far(u16 buf_seg, void *buf_far, u32 len)
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{
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SET_SEG(ES, buf_seg);
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u32 i;
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u8 sum = 0;
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for (i=0; i<len; i++)
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sum += GET_VAR(ES, ((u8*)buf_far)[i]);
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return sum;
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}
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u8
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checksum(void *buf, u32 len)
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{
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return checksum_far(GET_SEG(SS), buf, len);
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}
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size_t
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strlen(const char *s)
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{
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if (__builtin_constant_p(s))
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return __builtin_strlen(s);
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const char *p = s;
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while (*p)
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p++;
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return p-s;
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}
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int
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memcmp_far(u16 s1seg, const void *s1, u16 s2seg, const void *s2, size_t n)
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{
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while (n--) {
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int d = GET_FARVAR(s1seg, *(u8*)s1) - GET_FARVAR(s2seg, *(u8*)s2);
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if (d)
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return d < 0 ? -1 : 1;
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s1++;
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s2++;
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}
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return 0;
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}
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// Compare two areas of memory.
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int
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memcmp(const void *s1, const void *s2, size_t n)
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{
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while (n) {
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if (*(u8*)s1 != *(u8*)s2)
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return *(u8*)s1 < *(u8*)s2 ? -1 : 1;
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s1++;
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s2++;
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n--;
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}
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return 0;
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}
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// Compare two strings.
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int
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strcmp(const char *s1, const char *s2)
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{
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for (;;) {
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if (*s1 != *s2)
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return *s1 < *s2 ? -1 : 1;
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if (! *s1)
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return 0;
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s1++;
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s2++;
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}
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}
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inline void
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memset_far(u16 d_seg, void *d_far, u8 c, size_t len)
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{
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SET_SEG(ES, d_seg);
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asm volatile(
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"rep stosb %%es:(%%di)"
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: "+c"(len), "+D"(d_far)
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: "a"(c), "m" (__segment_ES)
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: "cc", "memory");
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}
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inline void
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memset16_far(u16 d_seg, void *d_far, u16 c, size_t len)
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{
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len /= 2;
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SET_SEG(ES, d_seg);
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asm volatile(
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"rep stosw %%es:(%%di)"
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: "+c"(len), "+D"(d_far)
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: "a"(c), "m" (__segment_ES)
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: "cc", "memory");
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}
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void *
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memset(void *s, int c, size_t n)
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{
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while (n)
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((char *)s)[--n] = c;
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return s;
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}
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void memset_fl(void *ptr, u8 val, size_t size)
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{
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if (MODESEGMENT)
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memset_far(FLATPTR_TO_SEG(ptr), (void*)(FLATPTR_TO_OFFSET(ptr)),
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val, size);
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else
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memset(ptr, val, size);
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}
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inline void
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memcpy_far(u16 d_seg, void *d_far, u16 s_seg, const void *s_far, size_t len)
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{
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SET_SEG(ES, d_seg);
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u16 bkup_ds;
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asm volatile(
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"movw %%ds, %w0\n"
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"movw %w4, %%ds\n"
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"rep movsb (%%si),%%es:(%%di)\n"
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"movw %w0, %%ds"
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: "=&r"(bkup_ds), "+c"(len), "+S"(s_far), "+D"(d_far)
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: "r"(s_seg), "m" (__segment_ES)
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: "cc", "memory");
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}
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inline void
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memcpy_fl(void *d_fl, const void *s_fl, size_t len)
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{
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if (MODESEGMENT)
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memcpy_far(FLATPTR_TO_SEG(d_fl), (void*)FLATPTR_TO_OFFSET(d_fl)
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, FLATPTR_TO_SEG(s_fl), (void*)FLATPTR_TO_OFFSET(s_fl)
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, len);
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else
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memcpy(d_fl, s_fl, len);
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}
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void *
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#undef memcpy
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memcpy(void *d1, const void *s1, size_t len)
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#if MODESEGMENT == 0
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#define memcpy __builtin_memcpy
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#endif
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{
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SET_SEG(ES, GET_SEG(SS));
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void *d = d1;
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if (((u32)d1 | (u32)s1 | len) & 3) {
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// non-aligned memcpy
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asm volatile(
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"rep movsb (%%esi),%%es:(%%edi)"
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: "+c"(len), "+S"(s1), "+D"(d)
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: "m" (__segment_ES) : "cc", "memory");
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return d1;
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}
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// Common case - use 4-byte copy
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len /= 4;
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asm volatile(
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"rep movsl (%%esi),%%es:(%%edi)"
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: "+c"(len), "+S"(s1), "+D"(d)
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: "m" (__segment_ES) : "cc", "memory");
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return d1;
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}
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// Copy to/from memory mapped IO. IO mem is very slow, so yield
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// periodically.
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void
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iomemcpy(void *d, const void *s, u32 len)
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{
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ASSERT32FLAT();
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yield();
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while (len > 3) {
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u32 copylen = len;
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if (copylen > 2048)
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copylen = 2048;
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copylen /= 4;
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len -= copylen * 4;
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asm volatile(
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"rep movsl (%%esi),%%es:(%%edi)"
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: "+c"(copylen), "+S"(s), "+D"(d)
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: : "cc", "memory");
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yield();
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}
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if (len)
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// Copy any remaining bytes.
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memcpy(d, s, len);
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}
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void *
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memmove(void *d, const void *s, size_t len)
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{
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if (s >= d)
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return memcpy(d, s, len);
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d += len-1;
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s += len-1;
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while (len--) {
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*(char*)d = *(char*)s;
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d--;
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s--;
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}
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return d;
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}
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// Copy a string - truncating it if necessary.
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char *
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strtcpy(char *dest, const char *src, size_t len)
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{
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char *d = dest;
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while (--len && *src != '\0')
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*d++ = *src++;
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*d = '\0';
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return dest;
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}
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// locate first occurrence of character c in the string s
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char *
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strchr(const char *s, int c)
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{
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for (; *s; s++)
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if (*s == c)
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return (char*)s;
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return NULL;
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}
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// Remove any trailing blank characters (spaces, new lines, carriage returns)
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char *
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nullTrailingSpace(char *buf)
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{
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int len = strlen(buf);
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char *end = &buf[len-1];
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while (end >= buf && *end <= ' ')
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*(end--) = '\0';
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while (*buf && *buf <= ' ')
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buf++;
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return buf;
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}
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