NS_CStringSetDataRange 编辑

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Summary

The NS_CStringSetDataRange function copies data into a section of the string's internal buffer. This is a low-level API.

#include "nsStringAPI.h"

nsresult NS_CStringSetDataRange(
  nsACString& aString,
  PRUint32 aCutStart,
  PRUint32 aCutLength,
  const char* aData,
  PRUint32 aDataLength = PR_UINT32_MAX
);

Parameters

aString

[in] A nsACString instance to modify.

aCutStart

[in] The starting index of the section to replace, measured in storage units.

aCutLength

[in] The length of the section to replace, measured in storage units.

aData

[in] A raw character array to copy into this string.

aDataLength

[in] The length of aData, measured in storage units. If equal to PR_UINT32_MAX, then aData is assumed to be null-terminated. Otherwise, aData need not be null terminated.

Return Values

The NS_CStringSetDataRange function returns NS_OK if successful. Otherwise, it returns an error code.

Example

// Replace all occurances of |matchVal| with |newVal|

void ReplaceSubstring(nsACString& str,
                      const nsACString& matchVal,
                      const nsACString& newVal)
{
  const char* sp, *mp, *np;
  PRUint32 sl, ml, nl;

  sl = NS_CStringGetData(str, &sp);
  ml = NS_CStringGetData(matchVal, &mp);
  nl = NS_CStringGetData(newVal, &np);

  for (const char* iter = sp; iter <= sp + sl - ml; ++iter)
  {
    if (memcmp(iter, mp, ml) == 0)
    {
      PRUint32 offset = iter - sp;

      NS_CStringSetDataRange(str, offset, ml, np, nl);

      sl = NS_CStringGetData(str, &sp);

      iter = sp + offset + nl - 1;
    }
  }
}

History

This function was frozen for Mozilla 1.7. See bug 239123 for details.

See Also

nsACString